Homebrew_PCBs

Hi,

first, the sanding did no good it impedes transfer.

I did however try more today.
It seems high temperature silicone produces good results, every time.

my observation is that stadard silicone tends to make a sizzling sound and
excretes some (BAD) fumes and liquid stuff (silicone oil, molten silicone,
who knows) that makes a transfer impossible. The high temp variety does
not do that.

what i tried next is to let the fuser cool off, and just when starting a
long PCB plug it in again. so i get a temperature gradient over the whole
length of the PCB. It seems at a cooler temperature the trasfer works,
although i did only this one quick experiment and am not sure.

Assuming the same thing of "melting" happens inside the printer fuser it
would explain why the fuser seems to destroy the printout (And why it
doesn't do that with high-temp silicone).

Now that high-temp silicone works is very good news indeed. However, with
8eur/310ml it is much more expensive than normal silicone (2-3eur).
Reducing the temperature in both printer fuser and laminating fuser seems
not a far-fetched option, as i know that this particular printer has a
very high fuser temperature problem anyway. My calculations show that
310ml would last well over 200 pages tho, so still cheaper than the photo
paper i buy.

I did make some photos of how i coat the paper, and will publish them at
some point...

ST

Stefan Trethan wrote:

>
> my observation is that stadard silicone tends to make a sizzling sound and
> excretes some (BAD) fumes and liquid stuff (silicone oil, molten silicone,
> who knows) that makes a transfer impossible. The high temp variety does
> not do that.
>

If you've looked at silicone that's had a long time to dry, it's quite
different than silicone that's relatively recently dried. Most likely
outgassing the remaining liquid when heated.

A bake at a temp higher than the fuser should get rid of this, I may try
tossing a sheet or two in the oven next time I cook something. It'll take care
of the normal drying part at the same time of course. All assuming the paper
will stand up to it.

And LOL it is a very bad thing to be testing this stuff late at night, I
wrapped one of my drums with a sheet that was still way too sticky. I didn't
even begin to check it before I stuck it through. But now I have 7 HP 6L
printers on hand so I'm set, they're a bargain on Ebay now and then.

Alan

>>
> If you've looked at silicone that's had a long time to dry, it's quite
> different than silicone that's relatively recently dried. Most likely
> outgassing the remaining liquid when heated.
> A bake at a temp higher than the fuser should get rid of this, I may
> try
> tossing a sheet or two in the oven next time I cook something. It'll
> take care
> of the normal drying part at the same time of course. All assuming the
> paper
> will stand up to it.
> And LOL it is a very bad thing to be testing this stuff late at night,
> I
> wrapped one of my drums with a sheet that was still way too sticky. I
> didn't
> even begin to check it before I stuck it through. But now I have 7 HP 6L
> printers on hand so I'm set, they're a bargain on Ebay now and then.
> Alan

I wouldn't put normal silicone (not heat resist) in the oven with food.
the fumes are quite bad, only do when well ventilated.
Anyway, the heat resistant stuff works, and i have done a few good
tansfers already. i will provide details later today.


ST

is the heat resistant stuff red in colour ?
Thomas
Anyway, the heat resistant stuff works, and i have done a few good
tansfers already. i will provide details later today.


ST



[Non-text portions of this message have been removed]

On Sun, 15 May 2005 15:27:00 +0700, Thomas <teecee@...> wrote:

> is the heat resistant stuff red in colour ?
> Thomas

Most, yes. there is als other colors.

ST

Stefan Trethan wrote:

>
> I wouldn't put normal silicone (not heat resist) in the oven with food.
> the fumes are quite bad, only do when well ventilated.

Well I was thinking more along the lines of using the waste heat for
something useful for a change after the cooking is done than about making acetic
acid casserole.. :)

Alan

On Sun, 15 May 2005 09:23:40 -0400, Alan King <alan@...> wrote:

> Stefan Trethan wrote:
>
>>
>> I wouldn't put normal silicone (not heat resist) in the oven with food.
>> the fumes are quite bad, only do when well ventilated.
> Well I was thinking more along the lines of using the waste heat for
> something useful for a change after the cooking is done than about
> making acetic
> acid casserole..
> Alan

Nah, i still don't like the idea. I tried to run it through the fuser to
evaporate this liquid, but it doesn't work.
I think the temperature is just enough to break down normal silicone. I
think it could work to reduce fuser temperature, because it seems at the
beginning of a board (when the board is coldest) it doesn't sizzle.

Whatever, using normal silicone is not a priority for me. High temp
silicone works and i accept the doubled cost for now, after all fiddling
around with the temperature is a lot of work too. Right now i'm fighting
with the printer for perfect geometry adjustment.

The things concerning the transfer so far are:


Do not put silicone on the first 7-10cm of the page or you will from then
on have a paper coated drum.
(By the way, drums and light-sensitivity, how bad is it really? which
precautions must be taken when working with drums?)

Work with relatively low pressure in the fuser.

Let cool before peeling off the paper.

Otherwise the results are pretty good.
I have a problem with creases forming on the last few cm of a page, but i
hope to figure that out, and also for small boards it is not an issue.
Also, if this particular printer gets eaten up by acetic acid i do not
care that much, more like hope nothing is left...

It also needs to be cleared if the acetic acid does remain on the surface
of cured silicone. I have wiped it with acetone to re-use and that does
not seem to be a problem at all.


Much of my efforts is going into the distortion thing at the moment, to
see if i can go ahead with the CNC or if there is no point.

ST

Is this the hi-temp silicone material sold in auto parts stores as
gasket sealant?

Norm

>
>
>>is the heat resistant stuff red in colour ?
>>Thomas
>>
>>
>
>
>Most, yes. there is als other colors.
>
>ST
>
>
>
>
>
>

--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.11.8 - Release Date: 5/10/2005

On Sun, 15 May 2005 09:08:43 -0700, Norm Stewart <normstewart@...>
wrote:

> Is this the hi-temp silicone material sold in auto parts stores as
> gasket sealant?
> Norm

This is "Silikon HT" by "HANNO" "für hitzebeständige Verfugungen".

I expect it is similar to liquid gasket from auto stores, as long as it is
high temp (200C+), however i bought it as high temperature silicone.

I guess this:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1267&item=7510111345&rd=1&ssPageName=WD1V>
is a possible source in the US, however, a big DIY store should have it
too.

What i noticed is that this one seems to have more acetic acid than my
normal silicone. You can't keep your head close when spreading it. But i
do not think this is important, it appears the lack of breakdown in the
fuser is what makes it work. (It cures very fast tho)

TIP: get screw-cap nozzles for all your silicone, it really works! slowly
but surely they come as standard even with the cheap silicones.


ST

Stefan Trethan wrote:

>
>
> Nah, i still don't like the idea. I tried to run it through the fuser to
> evaporate this liquid, but it doesn't work.

It'd take many many passes at a desired temp to dry it. You generally use a
somewhat higher temp to proof something against the desired temp.

> I think the temperature is just enough to break down normal silicone. I
> think it could work to reduce fuser temperature, because it seems at the
> beginning of a board (when the board is coldest) it doesn't sizzle.

Sizzling almost guarantees you still have liquid turning to gas and escaping
through the other parts of the material. Dry solids just melt. Silicone is
relatively inert so unlikely it even has a melting point that low, I'd find it
very hard to believe that the gas temp is anywhere near toner melting temp.
Melting hardly expands anything, almost has to be gasses if you're hearing
sounds, which implies remaining liquid.

>
> Whatever, using normal silicone is not a priority for me. High temp
> silicone works and i accept the doubled cost for now, after all fiddling
> around with the temperature is a lot of work too. Right now i'm fighting
> with the printer for perfect geometry adjustment.
>

But yes it's relatively dirt cheap anyway with how much you can cover. And
the real goal is ease so cooking is sort of a step backwards even if it works.
But with 15 mins plus of leftover heat every time the oven is used it may be
easy enough to try.

> The things concerning the transfer so far are:
>
>
> Do not put silicone on the first 7-10cm of the page or you will from then
> on have a paper coated drum.
> (By the way, drums and light-sensitivity, how bad is it really? which
> precautions must be taken when working with drums?)
>

LOL Been there done that. If it's even sticky enough to do this though I
think it's still maybe too sticky. If the only reason it's coming off the drum
is because that first 7-10 cm is pulling it off with other rollers, then little
bits are still probably sticking to the drum. May be a livable situation though
and just consider a new cartridge now and then a part of the ease of transfer,
it'd be $20 well spent for perfect transfers with little work. I can make mine
near perfect with the other papers, but the process is more tedious and I
usually say screw it and just touch up any problems.
And the answer for light is very, very sensitive. 600X600 is 33 million
pixels per page. So 10 seconds per page that laser is sweeping about 3+ dots
per microsecond. Fractions of millionths of a second per pixel, times the 2500
or so pages the cartridge is rated for, that's all the light that's supposed to
hit the drum. Any exposure to light degrades the whole drum evenly though, and
I think there is some recovery effect too. The lasers are red or infrared, so
that's what the drum works off of. The color it mainly reflects (green or blue
depending on type) should be more safe at low intensities than just white. I've
thought about making a green and blue single LEDs safelight for working with them.
I think the degrading though is not 'black image' but leaky drum so less dark
image from less attraction. Since it only takes a tiny bit of plastic to
protect the copper I doubt a poorer drum that makes lighter prints would pose a
problem really, whereas for prints you can't make your blacks look dark enough.
Still best to avoid of course.

The coatings are organic, so organic solvents are a no-no. I'm trying to
find the inorganic solvent they use to clean them, it should let me recover my
wrapped drum since what's remaining isn't stuck too badly. Had a friend in a
copier shop that knew all the details, but haven't gotten in touch with him yet,
and I don't remember which solvent was for what they also stripped typewriter
drums etc.

> Work with relatively low pressure in the fuser.
>
> Let cool before peeling off the paper.
>
> Otherwise the results are pretty good.
> I have a problem with creases forming on the last few cm of a page, but i
> hope to figure that out, and also for small boards it is not an issue.
> Also, if this particular printer gets eaten up by acetic acid i do not
> care that much, more like hope nothing is left...
>

Sounds like the back end of the paper is no longer in rollers, and this lets
it shrink. Maybe try a legal sheet with another 7-10cm on the end with no coating..

> It also needs to be cleared if the acetic acid does remain on the surface
> of cured silicone. I have wiped it with acetone to re-use and that does
> not seem to be a problem at all.
>
>
> Much of my efforts is going into the distortion thing at the moment, to
> see if i can go ahead with the CNC or if there is no point.
>

What printer are you using? There is a small amount of distortion in my 6L's
but it's so small I don't worry about it much. Because of the rotating to
linear conversion it'd be hard to be 100%, but it should be possible to map the
distortion and precompensate the original before printing. And what for the
CNC? If you're just talking drilling alignment etc, then use two opposite
corner holes and manually locate them. From where they are to where they should
be will tell you exactly what your scaling error in X and Y is, far easier to
compensate by math for the drill hole locations and simply match what your
printer puts out. The absolute error is small, doesn't affect any components
I've seen.

Of course if you have to have 100% exact dimensions then it much be
precompensated. Just for a general circuit board though a percent or even a few
doesn't matter as long as the holes are matched..

And with 3 corners (two opposite and one of the others) you can get accurate
scaling and rotation information. Align the three manually for their actual
locations and you can find all the other holes without even aligning to be
parallel to the axes. Some basic trig is all it takes.. But it's so easy to
move side to side and use two holes to be exactly aligned to X, then go up to
the corner and get scaling, that I only do the 2 corner scaling and align to
parallel manually. LOL really just lazy and haven't written the code for 3
point with rotation, wouldn't take 15 minutes to do it.

I am starting to work on the CNC again some for cutting more than drilling,
so maybe I'll write it up soon. Hardly even used the CNC for anything since I
started just making everything single sided and mount all DIPs etc live bug
style without any holes. So much faster to just not drill anything at all. But
nibbling out circular boards is a pita, so time to get it back up for my board
routing.

Alan

On Sun, 15 May 2005 14:25:35 -0400, Alan King <alan@...> wrote:

> Sizzling almost guarantees you still have liquid turning to gas and
> escaping
> through the other parts of the material. Dry solids just melt.
> Silicone is
> relatively inert so unlikely it even has a melting point that low, I'd
> find it
> very hard to believe that the gas temp is anywhere near toner melting
> temp.
> Melting hardly expands anything, almost has to be gasses if you're
> hearing
> sounds, which implies remaining liquid.
>

Ok, here what i see:
Some liquid is created, which i think also sizzles.
When i remove the board quickly the liquid is still there, and it can be
used to wipe partially toner off the board like a oil or solvent. i dunno
what it is, it is not there with high-temp silicone, no difference how
long you let cure, so i do assume it comes from non-high temp silicone.

>> Do not put silicone on the first 7-10cm of the page or you will from
>> then
>> on have a paper coated drum.
>> (By the way, drums and light-sensitivity, how bad is it really? which
>> precautions must be taken when working with drums?)
>>
> LOL Been there done that. If it's even sticky enough to do this
> though I
> think it's still maybe too sticky. If the only reason it's coming off
> the drum
> is because that first 7-10 cm is pulling it off with other rollers, then
> little
> bits are still probably sticking to the drum. May be a livable
> situation though
> and just consider a new cartridge now and then a part of the ease of
> transfer,
> it'd be $20 well spent for perfect transfers with little work. I can
> make mine
> near perfect with the other papers, but the process is more tedious and I
> usually say screw it and just touch up any problems.

I do not agree it is _still_ to sticky. it is too sticky, without still,
it will not get better.
Note i do not use uncured silicone, only fully cured. Silicone stays
sticky even when fully cured.

> And the answer for light is very, very sensitive. 600X600 is 33
> million
> pixels per page. So 10 seconds per page that laser is sweeping about
> 3+ dots
> per microsecond. Fractions of millionths of a second per pixel, times
> the 2500
> or so pages the cartridge is rated for, that's all the light that's
> supposed to
> hit the drum. Any exposure to light degrades the whole drum evenly
> though, and
> I think there is some recovery effect too. The lasers are red or
> infrared, so
> that's what the drum works off of. The color it mainly reflects (green
> or blue
> depending on type) should be more safe at low intensities than just
> white. I've
> thought about making a green and blue single LEDs safelight for working
> with them.
> I think the degrading though is not 'black image' but leaky drum so
> less dark
> image from less attraction. Since it only takes a tiny bit of plastic to
> protect the copper I doubt a poorer drum that makes lighter prints would
> pose a
> problem really, whereas for prints you can't make your blacks look dark
> enough.
> Still best to avoid of course.

Yes, best to avoid. the lexmark has a uncovered drum, and it can be
installed by stupid people, so i assume normal, short, low intensity light
will not damage it.

> The coatings are organic, so organic solvents are a no-no. I'm trying
> to
> find the inorganic solvent they use to clean them, it should let me
> recover my
> wrapped drum since what's remaining isn't stuck too badly. Had a friend
> in a
> copier shop that knew all the details, but haven't gotten in touch with
> him yet,
> and I don't remember which solvent was for what they also stripped
> typewriter
> drums etc.
>

Let me know what solvent you find. I have so far only needed a dry paper
tissue, since i wasn't quite silly enough to put in uncured silicone ;-)

>> I have a problem with creases forming on the last few cm of a page, but

> Sounds like the back end of the paper is no longer in rollers, and
> this lets
> it shrink. Maybe try a legal sheet with another 7-10cm on the end with
> no coating..

I do not have legal paper, but yes, for smaller boards it is not an issue.
I only noticed because of the big geometry test board.
I do not think it is because there are no rollers, the printer is pretty
badly made and there is no wide roller before the drum, like on a HP, just
a small transport to the left. The creases are there at the drum, 'cause
there is no toner in them. they are not really creases (folded/crumpled),
more like vallies in the paper, bent down in a u-shape, and not touching
the drum. Maybe it will go away when i sort out the feed skew. i think the
left edge runs against the guide, and the silicone is too sticky to allow
the page to turn slightly halfway in.

> What printer are you using? There is a small amount of distortion in
> my 6L's
> but it's so small I don't worry about it much. Because of the rotating
> to
> linear conversion it'd be hard to be 100%, but it should be possible to
> map the
> distortion and precompensate the original before printing.

A lexmark, and yes, i can compensate in X and Y, but the right Y is
different from the left Y. probably because of feed skew and laser
misalignent, the service manual (such a crap, not even a schematic),
describes how to fix it. I must move the printer from under the table to
on it before tho, and the table is full of ****, you know the story.

> And what for the
> CNC? If you're just talking drilling alignment etc, then use two
> opposite
> corner holes and manually locate them. From where they are to where
> they should
> be will tell you exactly what your scaling error in X and Y is, far
> easier to
> compensate by math for the drill hole locations and simply match what
> your
> printer puts out. The absolute error is small, doesn't affect any
> components
> I've seen.
> Of course if you have to have 100% exact dimensions then it much be
> precompensated. Just for a general circuit board though a percent or
> even a few
> doesn't matter as long as the holes are matched..
> And with 3 corners (two opposite and one of the others) you can get
> accurate
> scaling and rotation information. Align the three manually for their
> actual
> locations and you can find all the other holes without even aligning to
> be
> parallel to the axes. Some basic trig is all it takes.. But it's so
> easy to
> move side to side and use two holes to be exactly aligned to X, then go
> up to
> the corner and get scaling, that I only do the 2 corner scaling and
> align to
> parallel manually. LOL really just lazy and haven't written the code
> for 3
> point with rotation, wouldn't take 15 minutes to do it.

you. me it would take a month. I fear i can not use such code and must
compensate before print.

> I am starting to work on the CNC again some for cutting more than
> drilling,
> so maybe I'll write it up soon. Hardly even used the CNC for anything
> since I
> started just making everything single sided and mount all DIPs etc live
> bug
> style without any holes. So much faster to just not drill anything at
> all. But
> nibbling out circular boards is a pita, so time to get it back up for my
> board
> routing.
> Alan

Customers do not like to use bug style.
Use sheetmetal shears for round boards.


ST

Stefan Trethan wrote:

>
> I expect it is similar to liquid gasket from auto stores, as long as it is
> high temp (200C+), however i bought it as high temperature silicone.
>

Have some in the US that is black in black tube, for making formed gaskets in
the higher temp areas of the engine. Pretty damn hard to see toner on it though
I bet.. :)

>
> What i noticed is that this one seems to have more acetic acid than my
> normal silicone. You can't keep your head close when spreading it. But i
> do not think this is important, it appears the lack of breakdown in the
> fuser is what makes it work. (It cures very fast tho)
>

More solvent to keep it more liquid, takes more solvent for denser materials.
The normal stuff dries out and shrinks with heat, losing seal. The black is
more dense and solid on initial drying, so there's less to shrink.

I've never seen a melted silicone gasket, at least certainly not at any sort
of reasonable temp like 400 + F that you sometimes see in engines. It dries out
and gets hard with heat and leaks not soft is the problem, I wouldn't expect
just a fuser pass is melting it. For that matter I've used it in solder bath
before as an emergency replacement for latex mask, but not there for long so not
100% sure it couldn't melt at 700 deg or something..

The normal stuff still works ok as gasket in high temp areas if you have good
surfaces and it's under compression, it just doesn't stay pliant enough so you
have more of a tendency to leak in the long term.

PS This all reminds me, put a peppermint in the oven sometime. With the
oils boiling and sugars cooking it foams and carbonizes, producing a light
fluffy solid black cloud-like object that hardly seems right weight to volume
wise, and really doesn't look like it would have come from the mint you started
with. Used to work at Dominos, with always on ovens and mints and a little too
much time..

Alan

On Sun, 15 May 2005 15:00:28 -0400, Alan King <alan@...> wrote:

>
> PS This all reminds me, put a peppermint in the oven sometime. With
> the
> oils boiling and sugars cooking it foams and carbonizes, producing a
> light
> fluffy solid black cloud-like object that hardly seems right weight to
> volume
> wise, and really doesn't look like it would have come from the mint you
> started
> with. Used to work at Dominos, with always on ovens and mints and a
> little too
> much time..
> Alan

Or put a polystyrene cup in it at just enough heat to make it soften, and
watch the wonder of turning back time.


Take care with sweets, the mythbusters have put some big sweet under heat
and almost shot an assistant with fragments ;-)

ST

Stefan Trethan wrote:

> Ok, here what i see:
> Some liquid is created, which i think also sizzles.

Melt something. It sits there as a liquid. Anything sizzling has a gas
escaping. Can't see anything as moving and making noise if it is all sitting
there just melted and there isn't something expanding at a different rate.
Liquids won't just make noise sitting there on their own, a cup of water or oil
never sizzles by itself, and when it's heated and does it's the gas escaping
that does it. Water sizzles on a hot iron from the steam escaping, not from the
liquid part. You'd have to have a liquid with an unreal coefficient of
expansion to have it displace air enough to make a sound no matter how much you
heat it.

> When i remove the board quickly the liquid is still there, and it can be
> used to wipe partially toner off the board like a oil or solvent. i dunno
> what it is, it is not there with high-temp silicone, no difference how
> long you let cure, so i do assume it comes from non-high temp silicone.
>

Exactly, it is the solvent remaining in the silicone. The high temp simply
dries out more thoroughly in curing, the low temp just retains more in the cured
mix. Actually the high temp must be staying rubberized by something else, hard
to see it locking in solvent or atmospheric water enough to hold it at 600 deg plus.

Low temp is known to retain quite a bit of acid for a long time, sealing it
up will cause the acid vapor to eat up electronics. If you haven't let it cure
for a year you're not as done with the acid as you may think..

And after refreshing my memory a sec on the net, it does pull in atmospheric
water as part of the curing process, and that is also what eventually dries out.
So you may be driving off both remaining acid and water, there's just little
way it's the solids part melting, I've seen it survive much higher temps for a
very long time with little apparent change besides getting hard, it's just not a
surviving as a gasket at that point thus you need a higher temp version. Can't
see an elastomeric compound like this that's solid at room temp melting at such
a low temp.

Looking at the hardware store there are a couple that are based on the oily
liquid silicon. But even those should cure into an elastomer, maybe you're
reverting a partial cure but doubt it's really melting a fully cured rubberized
compound. Also this was a completely different product, even the high temp RTV
seems to be a much more normal type.


And recall RTV stands for Room Temperature Vulcanizing. Vulcanizing normally
takes higher temps, RTV is a special process for it to happen at room temp. And
it's slow, the full curing of these is also largely advanced by heat. Which
means if you haven't cooked it out there's still extra stuff in there unless
it's had a very long time to cure, it'd probably take 50 or 100 fuser passes to
cook it well enough. Used a bunch of different types of this stuff in many
applications over 20 years, and I've never had instance to think of it as
something that I was going to melt. Other things may happen but melting isn't
one I've ever seen at 200 deg C fusing temps or even 400 deg F engine temps.
May have to put some in the oven just to see what it does, I'd expect simply get
hard from anything I've ever seen before.




And while checking the hardware store and getting some high temp RTV (only
black so it'll be a pita probably to see), there was some really clear acrylic
sealant listed as super elastic so I got some to try. Flammable solvents so
would take some good drying and flame testing to make sure it won't result in
printer immolation, but it feels very good in the tube, worth a try could be
better than silicone. If it's pliant and adheres to copper, aluminum, crome,
glass, and many others as they say it might be very good. Same pricing level as
the high temp, little bit nastier solvents but worth a look. Ah toluene, good
old model airplane glue smell. Excellent feel and about perfect tackiness to a
small smear, time for some testing.

With 7 HP 6L's laying around now, it's also time to start working to mod one
to print direct to copper. I still think this can be accomplished by proper
techniques, my aluminum foil prints worked very well.

Alan

On Sun, 15 May 2005 18:57:52 -0400, Alan King <alan@...> wrote:

>
> And while checking the hardware store and getting some high temp RTV
> (only
> black so it'll be a pita probably to see), there was some really clear
> acrylic
> sealant listed as super elastic so I got some to try. Flammable
> solvents so
> would take some good drying and flame testing to make sure it won't
> result in
> printer immolation, but it feels very good in the tube, worth a try
> could be
> better than silicone. If it's pliant and adheres to copper, aluminum,
> crome,
> glass, and many others as they say it might be very good. Same pricing
> level as
> the high temp, little bit nastier solvents but worth a look. Ah
> toluene, good
> old model airplane glue smell. Excellent feel and about perfect
> tackiness to a
> small smear, time for some testing.

I agree silicone does not melt. not even if it burns.
I assume you are right, there are 2 liquids present. one beeing water or
acid, the other beeing some more oily liquid, maybe it is silicone oil, i
have read RTV silicone can be made more liquid with silicone oil (not sure
if this is true).
It would then be like a frying pan, the hot oil and water.

Also note soetimes i hear sizzling with a normal paper/toner/PCB transfer,
but much much less. I expect a tiny amount of water or something.


I would not attept the acrylic, because these _DO_ melt, in the fuser too
i would expect.

ST

Got an hour of PCB stuff in today, maybe more later.

The creases on the bottom of the page were from transport misalignent,
have adjusted that and they are away now.


In terms of transfer to pcb i have found two interesting things:

Peeling the paper off just as it leaves the fuser (still hot) results in
very good transfers, possibly better than leaving it to cool.

Using very little silicone (spread as thin as you can, so that the paper
comes through) results also in very good results.
It did work bad with low-temp silicone so i'm surprised. But thinner is
better 'cause cheaper and see-through (alignment).


I have made 2 flawless transfers of 4, and 2 with slight holes. must
experiment more to narrow down the problem.
re-use of paper is definitely possible, just remove all toner with acetone
if any is left.

3.3mil and 5mil line width is converted by the printer to the same width,
and provides a sharp transfer, but i fear underetching would get it.
Spacing of less than 10mil fuses together, but right now i use darkest
toner and using less migh allow lower spacing.

It seems it works after all.

ST

Since Stefan first posted his idea I've played around with this on and off... mostly off, but here's what works well for me.
Your mileage may vary.

1. Use high temp automotive gasket silicone (red).

2. Use two layers of masking tape at the outside edges of the paper to hold the squeegee .008" off the paper.
I'm using a 2" bar of acrylic as a squeegee. This of course gives you a coating of silicone 8 thousandths of an inch thick. Thinner than this and the toner can get in to the paper. Thicker and the transfered lines get mushy and distorted.

3. Let it cure -completely- for 4 to 7 days. Longer doesn't hurt.

4. I'm printing with a HP2100 laser printer, factory cartridges only. Off brands of toner don't always work.
The first time I use a piece of silicone paper I run the whole sheet, tape and all through the printer.

5. Lightly sand and clean PCB stock with lacquer thinner, not acetone. I've gotten very poor results using acetone, I don't know why. Trim the printed silicone paper to fit.

6. Run it 5 to 6 times through GBC Laminator.

7. Let cool and peel.

The results are 99.99% perfect, there's very little touch up.
To reuse the silicone paper, clean it with lacquer thinner and stick the leading edge to a carrier piece of paper with a glue stick.

That works for me every time.
Good luck,
Denny

Nice to hear someone was done work on it too. sadly i have to disagree on
almost all points.

On Mon, 16 May 2005 14:02:02 -0500, <milwiron@...> wrote:

> Since Stefan first posted his idea I've played around with this on and
> off... mostly off, but here's what works well for me.
> Your mileage may vary.
> 1. Use high temp automotive gasket silicone (red).

I agree on this one

> 2. Use two layers of masking tape at the outside edges of the paper to
> hold the squeegee .008" off the paper.
> I'm using a 2" bar of acrylic as a squeegee. This of course gives you a
> coating of silicone 8 thousandths of an inch thick. Thinner than this and
> the toner can get in to the paper. Thicker and the transfered lines get
> mushy and distorted.

I disagree on this one. I use a steel squeegee and wipe it off as thin as
i can, no spacers.
I found it works better than a thick layer. I hold the squeegee almost
vertical and apply a lot of force, basically scrape off as much as you
can. the fibers shine through but the toner does _not_ adhere to them.
When you believe there is nothing left on the squeegee, you are wrong, it
is still enough for 2 or 3 sheets.

> 3. Let it cure -completely- for 4 to 7 days. Longer doesn't hurt.

Don't see the need, even a thick layer (mm) is cured in half an hour, i
have used a coated paper after 30 minutes with no adverse effects.

> 4. I'm printing with a HP2100 laser printer, factory cartridges only.
> Off brands of toner don't always work.
> The first time I use a piece of silicone paper I run the whole sheet,
> tape and all through the printer.
> 5. Lightly sand and clean PCB stock with lacquer thinner, not acetone.
> I've gotten very poor results using acetone, I don't know why. Trim the
> printed silicone paper to fit.

I always use acetone, and have very good results. i do not like the
possible adverse effects to health of laquer thinner.


> 6. Run it 5 to 6 times through GBC Laminator.

Run one time through old copier fuser converted to slow speed with chicken
grill motor.

> 7. Let cool and peel.

peel when still hot. (thicker coating can be peeled cold, but thin coating
is better peeled hot)

> The results are 99.99% perfect, there's very little touch up.

the results are 100% perfect, if you have done nothing wrong (e.g. bad
cleaning, pits in silicone, creases..)

> To reuse the silicone paper, clean it with lacquer thinner and stick the
> leading edge to a carrier piece of paper with a glue stick.

I just print the sheet again. why do you stick it to another paper?
I will make another post with my process, step by step. Easier to follow
than my comments here.
It is good we have come to different results, so people can try both.

ST

well, all i know anyway.

I start out with several sheets of standard 80g copier paper, and the
silicone (red, high-temp).
Put a sheet on a flat surface (i use a mirror), then i put a bead of
silicone (10cm long) on one sheet.
Then i take the squeegee (20cm wide stainess with wood handle), and at an
angle of about 30 degree (paper/squeegee) spread it with 3 or 4 passes.
This is not so much to get the paper coated but more to get silicone on
the whole length of the squeegee.
Now i take the sqeegee almost vertical (hold with a fist) and scrape once
the whole page. The paper comes through. if it is uneven, or the paper
doesn't come through in places, scrape again. (Angle the squeegee down to
apply more silicone if there are still bare spots).
When a page is done, take the next one. You do not need a new bead, i
usually coat 5 pages or so with the initial bead, there is still enough on
the squeegee. You can start the second page on a very high angle of the
squeegee already. You will quickly get the hang of it. Scrape off as much
silicone as possible, at some point it will not be possible to scrape off
more without ripping the page.

I coat the hole page leaving about 1-2cm at the edge so i don't make the
glass dirty, i have found with the thin layer it does no longer wrap
around the drum if the leading edge is coated.

Now leave to cure, i usually test if the rest on the squeegee is cured,
because it is thicker material so takes longer, it is safe to assume the
paper is OK then. By the way it pulls off easily of the squeegee when
hard, no point wiping when soft.

With your sheet ready, print on it.

Prepare the PCB the usual way, sand with 600 or 1000 grit, and wipe with
acetone.
(hint: use your squeegee to scrape toner off pcbs of previous (faulty)
transfers, or after etching, you need less acetone).

Now simply put your printed sheet on the PCB and feed through the fuser.
with my motor speed one pass is enough. I use relatively low pressure on
the fuser rollers.

Peel as soon as it leaves the printer. you can feel when it is to cold, it
will be harder to peel, it comes off very easily while hot. I can allow
about 15cm to leave the fuser before it is cooled too much, so with a 20cm
board i must start to peel while still fusing.
It will also work if you let it cool and peel later, however i have
missing spots then sometimes.


When you have done everything right there will be no toner left on the
paper, and you can print on it again straightaway. if there is toner left
for some reason use acetone, even if the paper shines through the silicone
it will not become wet and soft.

Let me know if you need clarification somewhere, or pictures.

ST

On Mon, 16 May 2005 21:44:28 +0200, Stefan Trethan <stefan_trethan@...>
wrote:

> Peel as soon as it leaves the printer.

Make that: peel as soon as it leaves the fuser.

ST

>> 5. Lightly sand and clean PCB stock with lacquer thinner, not

acetone.

>> I've gotten very poor results using acetone, I don't know why. Trim

the

>> printed silicone paper to fit.

>I always use acetone, and have very good results. i do not like the
>possible adverse effects to health of laquer thinner.

Acetone is listed as a carcenogenic, not sure about the thinners.
Acetone
Is a horrible chemical in it's own right. We have acetone at work as we
Occasionally use it in the optical industry to clean factory marking off

Prescription optical lenses (anyone in the optical game will know this).

However with the advent of modern day resins, polycarbonates and
protective
Coatings we avoid it as much as possible as it can damage a lot now.

What we use instead is called 'Citro Clean', its like an acidic type
cleaner
Made from oranges etc. Don’t know how well this would work for required
task
But is certainly a lot more healthy for the user.

Cheers,

Andy S
http://www.remixreality.com

Stefan Trethan wrote:

>
> I would not attept the acrylic, because these _DO_ melt, in the fuser too
> i would expect.
>

Well picked it up because I can use it for its original use too, it's super
clear. But nothing to flame and oven test it, so may as well. If it flames
really well I may sacrifice an extra printer in the driveway a la the flaming
pop tart toaster experiments. If you haven't seen this try it, get a $5 yard
sale toaster and wire/tape the handle down, put in some pop tarts and plug it in
on the driveway. Make sure there is nothing flammable within 50 yards or about
50 feet overhead, you get 15-20 foot flames sometimes. There is a seperate FD
flamability chart for breakfast pastries.


Went to Walmart getting stuff and they had the bubble curtains. Aqua tech,
they had the green 1' stiff one, but also a flexible one that you can't see any
holes, looks smooth to the eye. Got one of each, figuring the flexible one may
have smaller holes etc. Also got a plastic 'stone' that's like a hollow tube
shape with a diffuser that looks like one of the plastic scouring pads. Was
only %1.50 or something so got it to try as well. I'll put up some pics for ID
purposes if any of them seem particularly useful.

Time to try out the high heat RTV, too bad it's black this will be fun I think..

Alan

I will not go into that discussion again, we have fought that battle a
long time ago and fighting over the same ground is useless. Acetone is not
carcinogenic, check _any_ MSDS, like
<http://www.purdue.edu/rem/home/booklets/Acetone%20MSDS.pdf>, carcinogenic
- not listed. Acetone production can use carcinogenic chemicals, and other
chemicals, like petrol, are carcinogenic too. IMO acetone is one of the
safer solvents.

That's all i i'll say about acetone beeing carcinogenic, see the archives
for the full discussion. I do not know where the misinformation about
acetone came from, but many people do believe it it seems. I have asked
for the slightest sliver of information about acetone beeing carcinogenic
and not a single URL was beeing produced in response. My point is made.

As for avoiding it, i'm sure other detergents can be used as well, or
alcohol. Ethanol would be an option (also for the new plastic lenses!),
and works well also. I have read the industry uses scrubbing under flowing
water for PCBs and no solvent at all.

ST

On Tue, 17 May 2005 08:37:20 +1000, Andrew <swinn05@...> wrote:

> Acetone is listed as a carcenogenic, not sure about the thinners.
> Acetone
> Is a horrible chemical in it's own right. We have acetone at work as we
> Occasionally use it in the optical industry to clean factory marking off
> Prescription optical lenses (anyone in the optical game will know this).
> However with the advent of modern day resins, polycarbonates and
> protective
> Coatings we avoid it as much as possible as it can damage a lot now.
> What we use instead is called 'Citro Clean', its like an acidic type
> cleaner
> Made from oranges etc. Don’t know how well this would work for required
> task
> But is certainly a lot more healthy for the user.
> Cheers,
> Andy S
> http://www.remixreality.com

On Tue, 17 May 2005 03:27:34 -0400, Alan King <alan@...> wrote:

>
> Well picked it up because I can use it for its original use too, it's
> super
> clear.

I didn't know there is super clear variety, interesting. I once tried to
use it to isolate contacts of a relais (mains voltage). It shortet them
right out in uncured state!.

> But nothing to flame and oven test it, so may as well. If it flames
> really well I may sacrifice an extra printer in the driveway a la the
> flaming
> pop tart toaster experiments. If you haven't seen this try it, get a
> $5 yard
> sale toaster and wire/tape the handle down, put in some pop tarts and
> plug it in
> on the driveway. Make sure there is nothing flammable within 50 yards
> or about
> 50 feet overhead, you get 15-20 foot flames sometimes. There is a
> seperate FD
> flamability chart for breakfast pastries.

Mythbusters did that, fragments shot one of the girls near the eye when
one exploded... on camera...

> Went to Walmart getting stuff and they had the bubble curtains. Aqua
> tech,
> they had the green 1' stiff one, but also a flexible one that you can't
> see any
> holes, looks smooth to the eye. Got one of each, figuring the flexible
> one may
> have smaller holes etc. Also got a plastic 'stone' that's like a hollow
> tube
> shape with a diffuser that looks like one of the plastic scouring pads.
> Was
> only %1.50 or something so got it to try as well. I'll put up some pics
> for ID
> purposes if any of them seem particularly useful.

I got black flexible hose. It is made of foam rubber, the outside is
smooth and has tiny holes punched in.
Works all right. I had to take out the lead wire in it (keeps it submerged
but CuCl eats lead for breakfast).

My 110l/h pump is just a tad small for 45cm hose, need to get a bigger
one, the last 5cm of the hose get no air. But no hurry..

ST

I stand corrected. I was sure I had read it in a MSDS at my previous
employer. Perhaps there
was an error in the information, as I no longer work there it is kind of
hard to check.

On a side note I looked at an online MSDS just before and noted this
piece of information
contained in the MSDS.

'Use of alcoholic beverages enhances toxic effects'

Must remember to pop away the beer next time i have a glass of acetone.
;)



Cheers,

Andy S

> I will not go into that discussion again, we have fought that battle a

> long time ago and fighting over the same ground is useless. Acetone is

not

> carcinogenic, check _any_ MSDS

[Non-text portions of this message have been removed]

On Tue, 17 May 2005 19:25:28 +1000, Andrew <swinn05@...> wrote:

>
> On a side note I looked at an online MSDS just before and noted this
> piece of information
> contained in the MSDS.
> 'Use of alcoholic beverages enhances toxic effects'
> Must remember to pop away the beer next time i have a glass of acetone.
>
> Cheers,
> Andy S

There must be some piece of misinformation that gets so many people to
believe acetone is carcinogenic. I suspect it is a confusion with the
strong-acid process used for acetone production beeing potentially
carcinogenic. (I wouldn't be surprised if it was created by the media,
using inaccurate facts)

However, yes, many msds i have seen say ethanol increases toxic effects.
But then, seeing it realistic, if you drink ethanol in any form i bet it
is much more dangerous than responsibly used acetone on it's own. I mean
those MSDS read like a horror story, sometimes, but if you compare with
substances that are consumed it is not that bad. Often you must really
ingest it or something to get the possible results described in te MSDS. I
just stay well clear of carcinogenic substances. All chemicals here in
europe have a very useful declaration sign, not sure if it is the same in
the US.

We have F for flammable, C corrosive, Xi for irritant, N for poison to
environment/water, and then it gets really nasty like Xn and T, which can
have permanent effects. I don't use Xn or T stuff, cause i think it is not
really worth it. I think such chemicals can be used safely with proper
precautions, but i just don't want to deal with it. (Electroless tin for
tinning PCBs is such a substance.)

These hazard symbols are a quick indication if you want to use it without
needing to find a MSDS. The abbrevations are obviously english but i
wouldn't expect the same symbols to be used in the US?

As said, i believe pcb cleaning is not something that requires getting
exposed to anything you think is dangerous, cause stuff like abrasive
kitchen cleaners work just as well.

ST

Hello Stefan,

Tuesday, May 17, 2005, 9:45:16 AM, you wrote:


ST> I got black flexible hose. It is made of foam rubber, the outside is
ST> smooth and has tiny holes punched in.
ST> Works all right. I had to take out the lead wire in it (keeps it submerged
ST> but CuCl eats lead for breakfast).



Put the led wire back, bt before obtain some lacquer (I used one for wooden boats) to protect it from CuCl or any other etchant.

--
Sincerely,
����``````````````````````````````````````````````````````����
ZAS ElMed | mailto:zasto@...
| http://www.zas-elmed.co.yu
| Tel/Fax: +381 11 344-0748
|
Zoran A. Scepanovic | Mob: +381 63 609-993
���,����������������������������������������,�������������,���

*********
Undetectable errors are infinite in variety, in contrast to detectable errors, which by definition are limited.
*********

[Non-text portions of this message have been removed]

On Tue, 17 May 2005 12:12:18 +0200, Zoran A. Scepanovic <zasto@...>
wrote:

> Put the led wire back, bt before obtain some lacquer (I used one for
> wooden boats) to protect it from CuCl or any other etchant.

I do not trust that paint to protect it long-term.

I simply stuck the hose to a plastic stick with hot-melt glue, holds it
down and straight.

ST

<stefan_trethan@g...> wrote:

> Nice to hear someone was done work on it too. sadly i have to disagree on
> almost all points.

> On Mon, 16 May 2005 14:02:02 -0500, <milwiron@t...> wrote:

> > 2. Use two layers of masking tape at the outside edges of the paper to
> > hold the squeegee .008" off the paper.
> > I'm using a 2" bar of acrylic as a squeegee.....

> I disagree on this one. I use a steel squeegee and wipe it off as thin as
> i can, no spacers.
> I found it works better than a thick layer. I hold the squeegee almost
> vertical and apply a lot of force, basically scrape off as much as you
> can....

Hi Stefan,
I'm not sure how you can say a method is "wrong" if it works for me.
What I posted works very well with the equipment and materials I have on hand.
I use a bar of acrylic because it's rigid, glass smooth and is easy to clean since any cured silicone just peels off. Using the acrylic bar and the masking tape spacers gives me perfect coatings of uniform thickness every time, it's one less variable to deal with.

> > 3. Let it cure -completely- for 4 to 7 days. Longer doesn't hurt.

> Don't see the need, even a thick layer (mm) is cured in half an hour, i
> have used a coated paper after 30 minutes with no adverse effects.

I get better results letting the silicone go through its full post cure period.
For years I worked with dozens upon dozens of different types of single and two part silicones in industrial applications, very few silicones are fully cured in a couple of hours.
Most of the silicones you'll ever run in to are compounded to be 100% solids after full cure, full cures can take days or even weeks. Less than a full cure and it's not 100% solid.

In my experiments I found that with anything less than a full cure I had the silicone sticking to the copper board and the toner not releasing entirely... the longer I let it sit the better it worked for transfers. And with a full cure there's no risk of gluing the silicone paper to a fuser roller or leaving behind any prepolymers to contaminate the printer.
Letting the silicone paper sit for a week isn't a big deal for me if I plan ahead. (No, planning ahead doesn't always happen)

> > 4. I'm printing with a HP2100 laser printer, factory cartridges only.
> > Off brands of toner don't always work.
> > The first time I use a piece of silicone paper I run the whole sheet,
> > tape and all through the printer.
> > 5. Lightly sand and clean PCB stock with lacquer thinner, not acetone.
> > I've gotten very poor results using acetone, I don't know why. Trim the
> > printed silicone paper to fit.

> I always use acetone, and have very good results. i do not like the
> possible adverse effects to health of laquer thinner.

One thing I learned in my Polymeric Chemistry courses is that all hydrocarbon and chlorinated solvents are hard on living tissue. If you think acetone is somehow better for you than lacquer thinner you're not looking at the whole picture.
Any solvent that can dissolve thermoplastics like polystyrene or acrylic will make a mess out of your liver, lungs and nervous system. The above also goes for "natural" solvents, orange oil based solvents are a tad scary. It's natural, yeah and it removes dried paint. Asbestos and uranium are natural too.

Cancer is bad no doubt, so is permanent damage your nervous system and have you tried to get a new liver lately? ;-)
The bottom line is, I've known people who died from cancer and others from liver failure and both together also. It's a tossup which one I'd choose.

Two over simplified but good to remember rules are:
1. If you can see it don't breath it.
2. If you smell it, it's too late.

Acetone has an affinity to water/moisture/humidity, something I've learned to try and avoid during copper cleaning before transfer.
To clean a board after etching and drilling I use a small sandblast cabinet with glass beads to clean off 99% of the toner in maybe 2 seconds. Then I use lacquer thinner for any minute traces of toner left behind.
I found if I used acetone at this point the copper traces and pads, if left uncoated, started to turn green at the edges after a day or two. This doesn't happen with lacquer thinner.
Again, these are my observations based on what I've run in to. Other people may get varied results.

About less potent stuff:
In my limited years of making toner transfer prototypes I've never had any success with soaps or detergents for cleaning the copper, even with distilled water rinses. Hopefully somebody has had better luck out there.

> > 6. Run it 5 to 6 times through GBC Laminator.

> Run one time through old copier fuser converted to slow speed with chicken
> grill motor.

GBC laminator, this is what works best for me.
I found 5 times quickly through a GBC laminator gives a more even heat and transfer than once through a slow fuser, I have both and it doesn't take any longer time-wise since the GBC is running 5 or 6 times faster.

> > 7. Let cool and peel.

> peel when still hot. (thicker coating can be peeled cold, but thin coating
> is better peeled hot)

> > The results are 99.99% perfect, there's very little touch up.

> the results are 100% perfect, if you have done nothing wrong (e.g. bad
> cleaning, pits in silicone, creases..)

I found peeling the paper when the board is hot can damage the transfer since the toner is still soft.
I prototyped a 3 x 6 inch board, every other board had a couple of 15 to 20 thousandths diameter pits of missing toner to fix. From your previous posts I didn't get the impression you were doing any better than that, I may be very wrong.

> > To reuse the silicone paper, clean it with lacquer thinner and stick the
> > leading edge to a carrier piece of paper with a glue stick.

> I just print the sheet again. why do you stick it to another paper?

I trim the silicone covered paper away from the uncoated paper for better registration on the board.
To get it to go through the printer after the first printing and trimming it needs a carrier sheet with my HP2100.

Once again, what I posted is what I found worked for me, I hope I made that clear in my first post. I was simply trying to share that information. If I somehow twisted your panties in a knot by posting, I humbly apologize.

Just a quick addition: I've found using commercially available .010 inch thick silicone sheeting attached to a carrier sheet of paper works extremely well and the preparation time is next to nothing. Best of all you don't have a dozen sheets of paper hanging around and laying on every horizontal surface in your shop.

I do greatly appreciate you sharing your original concept and experiments with silicone paper.
Denny

I have a GBC laminator also, it is wonderful, it's so consistent in
transferring the toner, I could never get a iron to work that well.

By the way, where did you find the silicone sheets? I would like to try them.


At 02:55 PM 5/17/2005, milwiron@... wrote:

><stefan_trethan@g...> wrote:
> > Nice to hear someone was done work on it too. sadly i have to disagree on
> > almost all points.
>
> > On Mon, 16 May 2005 14:02:02 -0500, <milwiron@t...> wrote:
>
> > > 2. Use two layers of masking tape at the outside edges of the paper to
> > > hold the squeegee .008" off the paper.
> > > I'm using a 2" bar of acrylic as a squeegee.....
>
> > I disagree on this one. I use a steel squeegee and wipe it off as thin as
> > i can, no spacers.
> > I found it works better than a thick layer. I hold the squeegee almost
> > vertical and apply a lot of force, basically scrape off as much as you
> > can....
>
>Hi Stefan,
>I'm not sure how you can say a method is "wrong" if it works for me.
>What I posted works very well with the equipment and materials I have on hand.
>I use a bar of acrylic because it's rigid, glass smooth and is easy to
>clean since any cured silicone just peels off. Using the acrylic bar and
>the masking tape spacers gives me perfect coatings of uniform thickness
>every time, it's one less variable to deal with.
>
> > > 3. Let it cure -completely- for 4 to 7 days. Longer doesn't hurt.
>
> > Don't see the need, even a thick layer (mm) is cured in half an hour, i
> > have used a coated paper after 30 minutes with no adverse effects.
>
>I get better results letting the silicone go through its full post cure
>period.
>For years I worked with dozens upon dozens of different types of single
>and two part silicones in industrial applications, very few silicones are
>fully cured in a couple of hours.
>Most of the silicones you'll ever run in to are compounded to be 100%
>solids after full cure, full cures can take days or even weeks. Less than
>a full cure and it's not 100% solid.
>
>In my experiments I found that with anything less than a full cure I had
>the silicone sticking to the copper board and the toner not releasing
>entirely... the longer I let it sit the better it worked for transfers.
>And with a full cure there's no risk of gluing the silicone paper to a
>fuser roller or leaving behind any prepolymers to contaminate the printer.
>Letting the silicone paper sit for a week isn't a big deal for me if I
>plan ahead. (No, planning ahead doesn't always happen)
>
> > > 4. I'm printing with a HP2100 laser printer, factory cartridges only.
> > > Off brands of toner don't always work.
> > > The first time I use a piece of silicone paper I run the whole sheet,
> > > tape and all through the printer.
> > > 5. Lightly sand and clean PCB stock with lacquer thinner, not acetone.
> > > I've gotten very poor results using acetone, I don't know why. Trim the
> > > printed silicone paper to fit.
>
> > I always use acetone, and have very good results. i do not like the
> > possible adverse effects to health of laquer thinner.
>
>One thing I learned in my Polymeric Chemistry courses is that all
>hydrocarbon and chlorinated solvents are hard on living tissue. If you
>think acetone is somehow better for you than lacquer thinner you're not
>looking at the whole picture.
>Any solvent that can dissolve thermoplastics like polystyrene or acrylic
>will make a mess out of your liver, lungs and nervous system. The above
>also goes for "natural" solvents, orange oil based solvents are a tad
>scary. It's natural, yeah and it removes dried paint. Asbestos and uranium
>are natural too.
>
>Cancer is bad no doubt, so is permanent damage your nervous system and
>have you tried to get a new liver lately? ;-)
>The bottom line is, I've known people who died from cancer and others from
>liver failure and both together also. It's a tossup which one I'd choose.
>
>Two over simplified but good to remember rules are:
>1. If you can see it don't breath it.
>2. If you smell it, it's too late.
>
>Acetone has an affinity to water/moisture/humidity, something I've learned
>to try and avoid during copper cleaning before transfer.
>To clean a board after etching and drilling I use a small sandblast
>cabinet with glass beads to clean off 99% of the toner in maybe 2 seconds.
>Then I use lacquer thinner for any minute traces of toner left behind.
>I found if I used acetone at this point the copper traces and pads, if
>left uncoated, started to turn green at the edges after a day or two. This
>doesn't happen with lacquer thinner.
>Again, these are my observations based on what I've run in to. Other
>people may get varied results.
>
>About less potent stuff:
>In my limited years of making toner transfer prototypes I've never had any
>success with soaps or detergents for cleaning the copper, even with
>distilled water rinses. Hopefully somebody has had better luck out there.
>
> > > 6. Run it 5 to 6 times through GBC Laminator.
>
> > Run one time through old copier fuser converted to slow speed with
> chicken
> > grill motor.
>
>GBC laminator, this is what works best for me.
>I found 5 times quickly through a GBC laminator gives a more even heat and
>transfer than once through a slow fuser, I have both and it doesn't take
>any longer time-wise since the GBC is running 5 or 6 times faster.
>
> > > 7. Let cool and peel.
>
> > peel when still hot. (thicker coating can be peeled cold, but thin
> coating
> > is better peeled hot)
>
> > > The results are 99.99% perfect, there's very little touch up.
>
> > the results are 100% perfect, if you have done nothing wrong (e.g. bad
> > cleaning, pits in silicone, creases..)
>
>I found peeling the paper when the board is hot can damage the transfer
>since the toner is still soft.
>I prototyped a 3 x 6 inch board, every other board had a couple of 15 to
>20 thousandths diameter pits of missing toner to fix. From your previous
>posts I didn't get the impression you were doing any better than that, I
>may be very wrong.
>
> > > To reuse the silicone paper, clean it with lacquer thinner and stick
> the
> > > leading edge to a carrier piece of paper with a glue stick.
>
> > I just print the sheet again. why do you stick it to another paper?
>
>I trim the silicone covered paper away from the uncoated paper for better
>registration on the board.
>To get it to go through the printer after the first printing and trimming
>it needs a carrier sheet with my HP2100.
>
>Once again, what I posted is what I found worked for me, I hope I made
>that clear in my first post. I was simply trying to share that
>information. If I somehow twisted your panties in a knot by posting, I
>humbly apologize.
>
>Just a quick addition: I've found using commercially available .010 inch
>thick silicone sheeting attached to a carrier sheet of paper works
>extremely well and the preparation time is next to nothing. Best of all
>you don't have a dozen sheets of paper hanging around and laying on every
>horizontal surface in your shop.
>
>I do greatly appreciate you sharing your original concept and experiments
>with silicone paper.
>Denny
>
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs
>Yahoo! Groups Links
>
>
>
>

Cecil Bayona
KD5NWA
www.qrpradio.com

'Never argue with an idiot. They drag you down to their level then beat you
with experience.'

On Tue, 17 May 2005 14:55:41 -0500, <milwiron@...> wrote:

> Hi Stefan,
> I'm not sure how you can say a method is "wrong" if it works for me.
> What I posted works very well with the equipment and materials I have on
> hand.
> I use a bar of acrylic because it's rigid, glass smooth and is easy to
> clean since any cured silicone just peels off. Using the acrylic bar and
> the masking
> tape spacers gives me perfect coatings of uniform thickness every time,
> it's one less variable to deal with.

I do not say it is wrong, never did. It is merely that my experiments have
let to different findings, in most points, which is surprising, at least.
This is still in the very early stages, nobody can possibly know anything
for sure.

> I get better results letting the silicone go through its full post cure
> period.
> For years I worked with dozens upon dozens of different types of single
> and two part silicones in industrial applications, very few silicones
> are fully
> cured in a couple of hours.
> Most of the silicones you'll ever run in to are compounded to be 100%
> solids after full cure, full cures can take days or even weeks. Less
> than a full cure
> and it's not 100% solid.
> In my experiments I found that with anything less than a full cure I had
> the silicone sticking to the copper board and the toner not releasing
> entirely...
> the longer I let it sit the better it worked for transfers. And with a
> full cure there's no risk of gluing the silicone paper to a fuser roller
> or leaving
> behind any prepolymers to contaminate the printer.
> Letting the silicone paper sit for a week isn't a big deal for me if I
> plan ahead. (No, planning ahead doesn't always happen)

It works for me when it no longer smears. I will try if if longer curing
makes for better cold-peel, might well be.

> One thing I learned in my Polymeric Chemistry courses is that all
> hydrocarbon and chlorinated solvents are hard on living tissue. If you
> think acetone is
> somehow better for you than lacquer thinner you're not looking at the
> whole picture.
> Any solvent that can dissolve thermoplastics like polystyrene or acrylic
> will make a mess out of your liver, lungs and nervous system. The above
> also goes
> for "natural" solvents, orange oil based solvents are a tad scary. It's
> natural, yeah and it removes dried paint. Asbestos and uranium are
> natural too.

Laquer thinner solves acrylic and polystyrene too.

> Cancer is bad no doubt, so is permanent damage your nervous system and
> have you tried to get a new liver lately?
> The bottom line is, I've known people who died from cancer and others
> from liver failure and both together also. It's a tossup which one I'd
> choose.
> Two over simplified but good to remember rules are:
> 1. If you can see it don't breath it.
> 2. If you smell it, it's too late.
> Acetone has an affinity to water/moisture/humidity, something I've
> learned to try and avoid during copper cleaning before transfer.

Whatever, all i know is Acetone is classified Xi, irritant, while laquer
thinner is Xn, possible bad permanent effects on health. Of course acetone
is bad on the liver, so is alcohol, and some people drink that.

> To clean a board after etching and drilling I use a small sandblast
> cabinet with glass beads to clean off 99% of the toner in maybe 2
> seconds. Then I use
> lacquer thinner for any minute traces of toner left behind.
> I found if I used acetone at this point the copper traces and pads, if
> left uncoated, started to turn green at the edges after a day or two.
> This doesn't
> happen with lacquer thinner.
> Again, these are my observations based on what I've run in to. Other
> people may get varied results.

Never seen this going green, i use another board edge or a steel squeegee
to scrape the toner off insead of blasting. Then i use acetone for the
rest. I would suspect the green stuff beeing caused by residual etchant, i
have had that when i didn't rinse properly. I can't figure out how acetone
would cause the discoloration, i would rather suspect the thinner putting
something on there which protects the copper?

> About less potent stuff:
> In my limited years of making toner transfer prototypes I've never had
> any success with soaps or detergents for cleaning the copper, even with
> distilled
> water rinses. Hopefully somebody has had better luck out there.

I used abrasive kitchen cleaner, and it did work, but i prefer the dry
method now.

> GBC laminator, this is what works best for me.
> I found 5 times quickly through a GBC laminator gives a more even heat
> and transfer than once through a slow fuser, I have both and it doesn't
> take any
> longer time-wise since the GBC is running 5 or 6 times faster.

I don't notice any uneven heat with the fuser, but i have no laminator. My
reasoning is the board cools between passes so one pass is ideal.

> I found peeling the paper when the board is hot can damage the transfer
> since the toner is still soft.
> I prototyped a 3 x 6 inch board, every other board had a couple of 15 to
> 20 thousandths diameter pits of missing toner to fix. From your previous
> posts I
> didn't get the impression you were doing any better than that, I may be
> very wrong.

I do get the holes when i peel cold, but not when i peel hot. Peeling cold
sometimes works 100%, but only sometimes, while peeling hot works all the
time.

> I trim the silicone covered paper away from the uncoated paper for
> better registration on the board.
> To get it to go through the printer after the first printing and
> trimming it needs a carrier sheet with my HP2100.

I see. the A3 size of the fuser is helping here i guess. In the end i most
likely end up cutting it and discarding the paper, 'cause i will want to
print multiple views on one sheet (like both copper and component legend
sides). I do not like the stick-to-carrier method, i noticed the toner
darkness is less when the paper is thicker.

> Once again, what I posted is what I found worked for me, I hope I made
> that clear in my first post. I was simply trying to share that
> information. If I
> somehow twisted your panties in a knot by posting, I humbly apologize.

You did not twist anything, just causing confusion by basically
contradicting many hours of painstaking experiments.

> Just a quick addition: I've found using commercially available .010 inch
> thick silicone sheeting attached to a carrier sheet of paper works
> extremely well
> and the preparation time is next to nothing. Best of all you don't have
> a dozen sheets of paper hanging around and laying on every horizontal
> surface in
> your shop.

Interesting, is it high-temp? i wouldn't have a source for such sheets
anyway i fear but it might be interesting for those who just can't find HT
silicone.

Also, would latex work? i remember someone mentioning using HT silicone as
replacement for latex masks... I can get liquid latex at my chemicals
supplier, but i wouldn't know if it can stand the heat...


ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"

> Also, would latex work? i remember someone mentioning using HT
>silicone as replacement for latex masks... I can get liquid latex at

my >chemicals

> supplier, but i wouldn't know if it can stand the heat...

Hi Stefan,
Liquid latex dries/cures in to an unvulcanized rubber, the toner would
bond right to it... if it was ever able to get past the heat in the
printer.

And yes, like acetone, lacquer thinner dissolves plastic, my point was
that it's all bad for living tissue.
Acetone may kill off parts of your nervous system before lacquer
thinner gives you cancer, in reality it's not much of a choice. We
just need to be aware of what we're working with and take the best
precautions we can.... then have a few beers and a pack of cigarettes
to celebrate our successes. ;-)
Denny

On Wed, 18 May 2005 11:57:20 -0000, milwiron <milwiron@...>
wrote:

> Hi Stefan,
> Liquid latex dries/cures in to an unvulcanized rubber, the toner would
> bond right to it... if it was ever able to get past the heat in the
> printer.

Tanks, then i needn't try.

> And yes, like acetone, lacquer thinner dissolves plastic, my point was
> that it's all bad for living tissue.
> Acetone may kill off parts of your nervous system before lacquer
> thinner gives you cancer, in reality it's not much of a choice. We
> just need to be aware of what we're working with and take the best
> precautions we can.... then have a few beers and a pack of cigarettes
> to celebrate our successes.
> Denny

Well, almost all is bad for living tissue. Hell, life itself is far too
dangerous for living tissue. All that moving around and breating and
ingesting, what a mess...

Everybody can read the MSDS of the solvents himself and choose how he
preferes to die ;-).

ST

--- In Homebrew_PCBs@yahoogroups.com, KD5NWA <KD5NWA@c...> wrote:

> By the way, where did you find the silicone sheets? I would like to

try them.

Hi,
The silicone sheet I have was a sample I conned from one of my suppliers.
It's actually not too rare, I know places like MacMaster Carr Supply
carry it in small quantities.
http://www.mcmaster.com/

Denny

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:

> Everybody can read the MSDS of the solvents himself and choose how he
> preferes to die ;-).

Amen, Brother Stefan. ;-)

Denny

Excuse me, a question please:
I remember having seen silicon spray might that or any other spray
type surface treatment do similar tricks ?
You guys are pioneering something real exciting there...
I wonder would this work for .5 mm pitch SMD pads (that's must be
something like 8 mil spaces and 11.68 mil pads)

Thanks

Tobias

On 5/18/05, milwiron <milwiron@...> wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@g...> wrote:
>
> > Everybody can read the MSDS of the solvents himself and choose how he
> > preferes to die ;-).
>
> Amen, Brother Stefan. ;-)
>
> Denny
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>

Stefan Trethan wrote:

> On Wed, 18 May 2005 11:57:20 -0000, milwiron <milwiron@...>
> wrote:
>
>
>>Hi Stefan,
>>Liquid latex dries/cures in to an unvulcanized rubber, the toner would
>>bond right to it... if it was ever able to get past the heat in the
>>printer.
>
>
> Tanks, then i needn't try.
>

Now don't go jumping to any crazy, non-scientific conclusions there. Most
solder mask is pure liquid latex, and survives 700 degrees wave soldering, so of
course it will survive a fuser.

>
> Well, almost all is bad for living tissue. Hell, life itself is far too
> dangerous for living tissue. All that moving around and breating and
> ingesting, what a mess...
>

Heard that. Pulled a muscle in my neck in the shower the other day, just now
getting where I can turn my head, what a pain in the neck! One solvent trying
to get at my nervous system, or 5 to 10 with some worse and all working on many
things trying to find the weakest spot, I know which one I'm sticking to.

Alan

On Wed, 18 May 2005 09:11:59 -0700, Tobias Gogolin <usertogo@...>
wrote:

> Excuse me, a question please:
> I remember having seen silicon spray might that or any other spray
> type surface treatment do similar tricks ?
> You guys are pioneering something real exciting there...
> I wonder would this work for .5 mm pitch SMD pads (that's must be
> something like 8 mil spaces and 11.68 mil pads)
> Thanks
> Tobias

I think silicone spray is the silicone oil, no?
If it is not and it hardens it would probably work.

the smd you mention would work if you reduce the padsize in the software.
Right now 10mil is the closest reliable spacing i can make before it
bridges from toner spreading (however this will get better if i used less
than darkest toner, must experiment more).

6.66mil is the smallest track i can etch without underetching causing
trouble. So i would set the pad to 6.66mil, which widens slightly from
spreading anyway, and have more than 10mil spacing left. I would expect it
to work.

Toner transfer was the really exciting thing, this merely makes the
process much easier. However i'm glad i had the stupid idea to smear some
silicone on a sheet of paper with a floppy disc...


ST

Hi Tobias,
The silicone oils and polysiloxane sprays that stay liquid or greasy wouldn't work. There are spray can/aerosol silicones by Loctite in their Superflex line, including high temperature, that turn to 100% solids. I don't think they'd be as good as Stefan's squeegee method of coating the paper but honestly I've never used them.
Denny

On Wed, 18 May 2005 09:11:59 -0700, Tobias Gogolin wrote:
> Excuse me, a question please:
> I remember having seen silicon spray might that or any other spray
> type surface treatment do similar tricks ?
> You guys are pioneering something real exciting there... I wonder
> would this work for .5 mm pitch SMD pads (that's must be something
> like 8 mil spaces and 11.68 mil pads)
>
> Thanks
>
> Tobias

On Wed, 18 May 2005 12:20:34 -0400, Alan King <alan@...> wrote:

>
> Now don't go jumping to any crazy, non-scientific conclusions there.
> Most
> solder mask is pure liquid latex, and survives 700 degrees wave
> soldering, so of
> course it will survive a fuser.
>

Ok so i will have to try. I was eager to abandon the idea 'cause i will
feel kind of foolish asking for it in the shop after i have found out by
accident what some people do with it (while searching for the article list
of that shop on the web). I certainly did not need to know that....

By the way i did not know soldermask is latex? seems harder than i would
expect?

ST

Hi Alan,
This is an area I don't know much about, how production boards are made. I buy 'em but I really don't know details of the process.
From every production board I've seen the solder mask appears to be an epoxy of some sort- single part, two part, UV cure, etc. Anyhow, it's a clear tinted thermoset plastic material, my guess is epoxy.

I've seen natural liquid latex rubber used for peelable paint masks but nothing that resembles latex rubber on a PC board.
For a couple of seconds max. natural latex rubber could take the heat but not for much longer unless it's a sacrificial coating.
With hundreds of newer, easier to handle and non-shrinking materials why would anyone use liquid latex rubber as a solder mask?
Just curious, thanks,
Denny

On Wed, 18 May 2005 12:20:34 -0400, Alan King wrote:
>>>�Hi Stefan,
>>>�Liquid latex dries/cures in to an unvulcanized rubber, the
>>>�toner would bond right to it... if it was ever able to get past
>>>�the heat in the printer.

>�Now don't go jumping to any crazy, non-scientific conclusions
>�there. �Most solder mask is pure liquid latex, and survives 700
>�degrees wave soldering, so of course it will survive a fuser.

Why not try a 5 second search on Google?

http://www.staticspecialists.com/techspray.html

Didn't mention a word about it being the film mask on a board, you've clearly
never been around an electronics production assembly environment, everyone uses
this stuff. While much of it is synthetic now to avoid the smells and for later
water dissolve, natural works just fine regardless of any nay-saying, certainly
good enough for a basic test. Still reasonably pliant after preheat and 10 or
12 seconds in a 700 deg solder bath since it peels in one piece, it's not nearly
as weak as you're suggesting.

Alan



milwiron@... wrote:

> Hi Alan,
> This is an area I don't know much about, how production boards are made. I buy 'em but I really don't know details of the process.
> From every production board I've seen the solder mask appears to be an epoxy of some sort- single part, two part, UV cure, etc. Anyhow, it's a clear tinted thermoset plastic material, my guess is epoxy.
>
> I've seen natural liquid latex rubber used for peelable paint masks but nothing that resembles latex rubber on a PC board.
> For a couple of seconds max. natural latex rubber could take the heat but not for much longer unless it's a sacrificial coating.
> With hundreds of newer, easier to handle and non-shrinking materials why would anyone use liquid latex rubber as a solder mask?
> Just curious, thanks,
> Denny
>
> On Wed, 18 May 2005 12:20:34 -0400, Alan King wrote:
>
>>>> Hi Stefan,
>>>> Liquid latex dries/cures in to an unvulcanized rubber, the
>>>> toner would bond right to it... if it was ever able to get past
>>>> the heat in the printer.
>
>
>> Now don't go jumping to any crazy, non-scientific conclusions
>> there. Most solder mask is pure liquid latex, and survives 700
>> degrees wave soldering, so of course it will survive a fuser.
>
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>
>
>

Stefan Trethan wrote:

> On Wed, 18 May 2005 12:20:34 -0400, Alan King <alan@...> wrote:
>
>
>> Now don't go jumping to any crazy, non-scientific conclusions there.
>>Most
>>solder mask is pure liquid latex, and survives 700 degrees wave
>>soldering, so of
>>course it will survive a fuser.
>>
>
>
>
> Ok so i will have to try. I was eager to abandon the idea 'cause i will
> feel kind of foolish asking for it in the shop after i have found out by
> accident what some people do with it (while searching for the article list
> of that shop on the web). I certainly did not need to know that....
>
> By the way i did not know soldermask is latex? seems harder than i would
> expect?
>

PS but first, History channel Modern Marvels tonight has rubber as the
subject for one of the hours, should repeat again in 3-4 hours.

Anything that masks solder is solder mask, no one said it had to be what
comes attached to the board. There are probably 5 or 10 other things commonly
used as solder mask, liquid rubber types and tapes are the most common. You
guys do realize that they use SOMETHING to keep solder off gold fingers and
other holes to be hand soldered after the wave don't you? It's called mask, it
isn't all about the board..


And yep people in general have about a 5 y. o. mentality. Happened to see
the Oprah show last week on colon health, and while there were a few admittedly
funny thing it wore thin fast how often they stopped the show to giggle over the
same dumb things they just laughed about 15 seconds ago, you'd think it was a
kindergarten class for the audience.. Bunch of Beavis and Buttheads in the
world, and usually the same people who'd swear up and down they weren't that
ignorant if you asked them. Can't let the idiots stop you though..

No idea if it will work well for toner transfer, but it definitely has the
right kind of properties after seeing it in action in a solder wave machine.


PPS they had fire rated silicone caulk at Lowe's here, $13 and $15 for gray
and red 10 oz tubes respectively. Not cheap but maybe not bad vs $10/50 sheet
paper or similar since it'd probably do 100 or 200 sheets or more.

Had another kind that was only $4/tube, said high heat but then only to 100
deg F in the text, for not drying out fast I assume. May still stand up to a
fuser pass or two.

Alan

On Wed, 18 May 2005 22:09:57 -0400, Alan King <alan@...> wrote:

> Anything that masks solder is solder mask, no one said it had to be
> what
> comes attached to the board. There are probably 5 or 10 other things
> commonly
> used as solder mask, liquid rubber types and tapes are the most common.
> You
> guys do realize that they use SOMETHING to keep solder off gold fingers
> and
> other holes to be hand soldered after the wave don't you? It's called
> mask, it
> isn't all about the board..

i see, thanks, will try it.

ST

>PS but first, History channel Modern Marvels tonight has rubber as the
> subject for one of the hours, should repeat again in 3-4 hours.

Alan,
Yes, I said up front I've never been around PC board production but I'll have to thank you anyhow for your condescending replies, I'm sure it was the absolute best you could offer.
It never ceases to amaze me that asking a serious, simple, polite question can result in such a smart ass attempt at a reply.
Are you too intelligent for the rest of us, or too impatient to pointedly answer a question? Oops, I really don't want an answer.

Anyhow, a whole hour on the History Channel, who boy I am sorry I wasted all that time and money on Engineering and Polymeric Tech. courses.

Just study notes alone concerning rubber, I've got a 4 inch thick notebook on natural elastomers and another on synthetic elastomers up in the attic plus a couple decades of work experience. If your "5 second search on Google", label reading or watching "Oprah" doesn't give you all the education you need you may want to try Dr. Phil.

Thanks again,
Denny

On Thu, 19 May 2005 08:27:08 -0500, <milwiron@...> wrote:

>
> Alan,
> Yes, I said up front I've never been around PC board production but I'll
> have to thank you anyhow for your condescending replies, I'm sure it was
> the
> absolute best you could offer.
> It never ceases to amaze me that asking a serious, simple, polite
> question can result in such a smart ass attempt at a reply.
> Are you too intelligent for the rest of us, or too impatient to
> pointedly answer a question? Oops, I really don't want an answer.
> Anyhow, a whole hour on the History Channel, who boy I am sorry I wasted
> all that time and money on Engineering and Polymeric Tech. courses.
> Just study notes alone concerning rubber, I've got a 4 inch thick
> notebook on natural elastomers and another on synthetic elastomers up in
> the attic plus a
> couple decades of work experience. If your "5 second search on Google",
> label reading or watching "Oprah" doesn't give you all the education you
> need you
> may want to try Dr. Phil.
> Thanks again,
> Denny

Denny,

To be honest, what i need is a guy that says i have used latex for
soldermask, been there, done that, it holds up under soldering temperature.

It is nice also to have a guy who tells me he has learned it will not
stand up to fuser temperature, but you see, for me experience is much more
useful than the notebooks up in the attic. Been there, done that, is so
useful because i can go there, do that, too.

Play nicely.

ST

milwiron@... wrote:

>> PS but first, History channel Modern Marvels tonight has rubber as the
>> subject for one of the hours, should repeat again in 3-4 hours.
>
>
> Alan, Yes, I said up front I've never been around PC board production but
> I'll have to thank you anyhow for your condescending replies, I'm sure it was
> the absolute best you could offer. It never ceases to amaze me that asking a
> serious, simple, polite question can result in such a smart ass attempt at a
> reply. Are you too intelligent for the rest of us, or too impatient to
> pointedly answer a question? Oops, I really don't want an answer.

Maybe you should read it again, I simply said why NOT try searching on Google
when you don't recognize what something is..

>
> Anyhow, a whole hour on the History Channel, who boy I am sorry I wasted all
> that time and money on Engineering and Polymeric Tech. courses.

I would be too if you were seriously thinking that latex would just fall
apart at a little heat.

>
> Just study notes alone concerning rubber, I've got a 4 inch thick notebook on
> natural elastomers and another on synthetic elastomers up in the attic plus a
> couple decades of work experience. If your "5 second search on Google", label
> reading or watching "Oprah" doesn't give you all the education you need you
> may want to try Dr. Phil.
>

I find it highly ironic that you'd make fun of that, you do realize that
every single person who might have searched 'latex solder mask' would have been
more knowledgable than yourself on it shortly after that five seconds? Far more
sage advice than you seem to give it credit for being.

Dr. Phil might not be a bad idea though, maybe he took some chem courses and
his books had a bit more info on what latex can actually handle. Real world
doesn't care much what it said in some book.

Alan

In article <opsqwyvbxmmg0lsf@...>,
Stefan Trethan <stefan_trethan@...> wrote:

> As said, i believe pcb cleaning is not something that requires getting
> exposed to anything you think is dangerous, cause stuff like abrasive
> kitchen cleaners work just as well.

In the UK, and I guess the rest of Europe, we have to do COSHH (control of
substances hazardous to health) assesments for all substances used on a
commercial site. This includes not just process chemicals (where used) but
stuff that is to be used by cleaners and even in the kitchens.

No, not the food obviously, though there are differing opinions on this :-)

Some of these products may well be the same as those available to the home
consumer and when you see what's in some of them.......

<fx> hair stands on end!

Stuart

On Tue, 07 Jun 2005 23:33:53 +0200, lists
<stuart.winsor.lists@...> wrote:

>
> In the UK, and I guess the rest of Europe, we have to do COSHH (control
> of
> substances hazardous to health) assesments for all substances used on a
> commercial site. This includes not just process chemicals (where used)
> but
> stuff that is to be used by cleaners and even in the kitchens.
> No, not the food obviously, though there are differing opinions on this
> Some of these products may well be the same as those available to the
> home
> consumer and when you see what's in some of them.......
> <fx> hair stands on end!
> Stuart

Is it the F Xi Xn T... rating with the nice pictures in the UK too?
I didn't know it was called COSHH

ST

>> No, not the food obviously, though there are differing opinions on this


>
> Is it the F Xi Xn T... rating with the nice pictures in the UK too?
> I didn't know it was called COSHH
>
> ST
>

While we are at hazard ratigs.
Only a few days ago i was curious how those "Salmiak" stones are meant to
be used to clean copper tips on soldering irons.
So i did a google search.

Turns out salmiak (ammonium chloride) has Xn rating, which is something i
try to avoid. (bad effects on health).

Turns also out they put it in food stuff!

In the one hand you want to avoid nasty stuff in the workshop, and then
they mix it right into food without sticking a Xn label on. I think they
definitely should have to label food. Also, it shows this rating doesn't
tell you too much.

ST

>
> Turns also out they put it in food stuff!
>
> In the one hand you want to avoid nasty stuff in the
> workshop, and then
> they mix it right into food without sticking a Xn label on. I
> think they
> definitely should have to label food. Also, it shows this
> rating doesn't
> tell you too much.
>
> ST

Maybe it is hidden in amongst all those nasty numbers that
are found in the ingredients list of most things these days.

I know my Aunt has a bad reaction to some of these additives
and as a rule wont buy anything that has a 'number' in the
ingredients list.

Andy S

On Wed, 08 Jun 2005 04:43:52 +0200, Andrew <swinn05@...> wrote:

>
> I know my Aunt has a bad reaction to some of these additives
> and as a rule wont buy anything that has a 'number' in the
> ingredients list.
> Andy S

Now that's slightly unreasonable ;-), 'cause one company might put the
same numbers in just write out the names ;-)
Wouldn't it be better if your aunt found out which numbers are the bad
ones?


ST

>
> >
> > I know my Aunt has a bad reaction to some of these
> additives and as a
> > rule wont buy anything that has a 'number' in the ingredients list.
> > Andy S
>
>
> Now that's slightly unreasonable ;-), 'cause one company
> might put the
> same numbers in just write out the names ;-)
> Wouldn't it be better if your aunt found out which numbers
> are the bad
> ones?
>
>
> ST

Unfortunately she has a reaction to most of the more popular
additives. I try to avoid a few of the 'nasty' ones but all
in all sometimes I can't be stuffed. :)

In article <op.sr0trhqimg0lsf@st>,
Stefan Trethan <stefan_trethan@...> wrote:

> Is it the F Xi Xn T... rating with the nice pictures in the UK too?

Yes

> I didn't know it was called COSHH

It's what the regulations are called here.