Homebrew PCBs

On Mon, 23 May 2005 12:32:05 -0400, microsoftwarecontrol  
<microsoftwarecontrol@...> wrote:

>
> I found well agitation is really esantial in etching. Uneven should be
> eliminated at all.
> I found a small cycling pump for chemistries, I only worry about flow  
> rate
> of it. After
> I real test it, I will give result here.
> By the way, I think of glueing a narrow glass tank with bottom been  
> heated.
> Is that kind of glue for home aquarium glass tank, OK? Can it take 70C?


I am not sure etchant pumping is the ideal agitation, there will always be  
currents etc.
Small air bubbles work for me..


I dunno which glue you mean, probably silicone, and that should be fine at  
70C.
But then, no etchant i know can be operated at 70C, what are you using?!?

ST

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, May 23, 2005 11:01 AM
Subject: Re: [Homebrew_PCBs] You guys have a look at this:


> On Mon, 23 May 2005 11:54:09 -0400, microsoftwarecontrol
> <microsoftwarecontrol@...> wrote:
>
> > I really get high quality pcb. One of important tool
> > is accurate temperature control from my tmpr module.
> > http://ca.geocities.com/microsoftwarecontrol/tmpr/tmpr.htm
> > Now, all other points in home PCB is solved perfectly, only problem
> > to me is etching uneven! I prepare to build a contant temperature tank,
> > with
> > fuild in cycling.
> > By the way, if any body need my tmpr module, you can email me. I will
> > enjoy
> > my time turn out with some cash. And only if you can handle 110
> > electricity.
> >
>
>
> Nice work there..
>
> What sort of etchant agitation do you use?
> I found with smaller bubbles from the bubbler hose my etching is OK now.
> It is still faster at the bottom edge, but that is to be expected .

I found well agitation is really esantial in etching. Uneven should be
eliminated at all.
I found a small cycling pump for chemistries, I only worry about flow rate
of it. After
I real test it, I will give result here.

By the way, I think of glueing a narrow glass tank with bottom been heated.
Is that kind of glue for home aquarium glass tank, OK? Can it take 70C?

>
> ST
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>
>
>

The 1st problem with pumping etchant is the metal parts in the system;
corrosion will rapidly become an issue.

I'm fabricating an etching bath myself.  I'll post results as soon as my
finger heals, a little slip while fixing the clothes dryer.  :)  I'm staying
away from chemicals until the skin heals even if I wear gloves.

At 1st I thought that making air bubbles in the etchant was going to be a
breeze, yeah right.  I quickly realized that air pressure, size and number
of holes, and adequate 'return' circulation had to be balanced; the stronger
the air bubbles going up, the more flow is generated upwards, so you need
more space for the flow to return to the bottom to complete the cycle.  My
1st attempt using water resulted in a nice volcano effect and my wife
yelling at me for messing up the place.  :D

I blocked the holes at both ends of the tubing grid and reduced the number
of holes along the middle area.  I found a nice balance where I get decent
bubbles, limitted splashing (a cover will still be essential), and a good
return flow down both ends of the vertical bath.  I have a plan for 2 large
PVC pipes to return the flow back to the bottom.  This will maximize the use
of the chamber for PCBs, as it stands, 2-3 inches at both ends lack bubbles.

I have yet to fabricate the holder to dip the PCBs in the solution, that's
my last TO-DO item.  I use a shop compressor, mated a quick release air
fixture onto the PVC piping, Gardena quick release garden hose fixtures
mated onto the PVC piping so I can easily remove the tubing grid from the
chamber for cleaning.  I use an ordinary valve to limit the air flow into
the system, and I also bleed additionnal air leak at the compressor.  I've
found that small pumps were just a tad weak, I prefer to use a stronger
source and limit the output.

As soon as I've burned some boards I'll post pics of the assembly.

Robert
:)



-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] De
la part de Stefan Trethan
Envoyé : mai 23 2005 11:39
À : Homebrew_PCBs@yahoogroups.com
Objet : Re: Re1: [Homebrew_PCBs] You guys have a look at this:


On Mon, 23 May 2005 12:32:05 -0400, microsoftwarecontrol  
<microsoftwarecontrol@...> wrote:

>
> I found well agitation is really esantial in etching. Uneven should be 
> eliminated at all. I found a small cycling pump for chemistries, I 
> only worry about flow
> rate
> of it. After
> I real test it, I will give result here.
> By the way, I think of glueing a narrow glass tank with bottom been  
> heated.
> Is that kind of glue for home aquarium glass tank, OK? Can it take 70C?


I am not sure etchant pumping is the ideal agitation, there will always be  
currents etc.
Small air bubbles work for me..


I dunno which glue you mean, probably silicone, and that should be fine at  
70C.
But then, no etchant i know can be operated at 70C, what are you using?!?

ST



Be sure to visit the group home and check for new Bookmarks and files:
http://groups.yahoo.com/group/Homebrew_PCBs 
Yahoo! Groups Links

Robert,


You have too big holes, too few holes, and perhaps too much air.
I had the "currents" too in the past.

Now that i use a aquarium bubbler hose there are many many tiny bubbles  
that do not create that forceful circulation.
Also, because the hose is over the whole length it lifts the water evenly,  
and there are not big circular currents possible.
It s still mixing the etchant well.

For a etchant pump, aquarium centrifugal pumps are available with  
no-metal, even cheap ones. But i don't think that is a good idea.

As for a holder, i have devised the following:
You need two plastic plates about 5cmx6cm. mount one at right angles to  
your lid, in the center. then mount a little sqare plastic stick (as  
spacer) along it to the lid (10mm wide). the second plate is now set  
against the first plate, the spacer keeps it apart at the lid and it forms  
sort of tongs. Cut a 5cm bicycle hose piece and slip it over the two  
pieces to spring-hold them together.

Now drill a hole in the lid, through the 10mm spacer (ideally you do this  
first). if you insert a round plastic stick here and press it down it  
forces the two plates (tongs) to open. You can spring-load the stick so it  
comes up on itself, then the holder is single-hand operation, and no  
touching of immersed parts. (The lid also needs a handle of course).

For better grip put a 1cm wide piece of bicycle hose over the end of the  
fixed plate (maybe glue). and cut the pivoting plate 2mm shorter so  
inserted PCBs are pressed straight against the fixed plate, which is at  
right angles.


A variation is possible to the round rod that opens the holder, if you  
make a paddel at the end inside the clamp it can be opened by rotating  
this stick. make a lever on the top, so that you can easily pull it  
parallel with the handle. Both versions seem to work well, but with the  
lever you can open several clamps with one hand, e.g. for allowing several  
small or one big pcb in your tank at once.


ST




On Mon, 23 May 2005 19:05:45 -0400, Robert Hedan  
<robert.hedan@...> wrote:

> The 1st problem with pumping etchant is the metal parts in the system;
> corrosion will rapidly become an issue.
> I'm fabricating an etching bath myself.  I'll post results as soon as my
> finger heals, a little slip while fixing the clothes dryer.    I'm  
> staying
> away from chemicals until the skin heals even if I wear gloves.
> At 1st I thought that making air bubbles in the etchant was going to be a
> breeze, yeah right.  I quickly realized that air pressure, size and  
> number
> of holes, and adequate 'return' circulation had to be balanced; the  
> stronger
> the air bubbles going up, the more flow is generated upwards, so you need
> more space for the flow to return to the bottom to complete the cycle.   
> My
> 1st attempt using water resulted in a nice volcano effect and my wife
> yelling at me for messing up the place.
> I blocked the holes at both ends of the tubing grid and reduced the  
> number
> of holes along the middle area.  I found a nice balance where I get  
> decent
> bubbles, limitted splashing (a cover will still be essential), and a good
> return flow down both ends of the vertical bath.  I have a plan for 2  
> large
> PVC pipes to return the flow back to the bottom.  This will maximize the  
> use
> of the chamber for PCBs, as it stands, 2-3 inches at both ends lack  
> bubbles.
> I have yet to fabricate the holder to dip the PCBs in the solution,  
> that's
> my last TO-DO item.  I use a shop compressor, mated a quick release air
> fixture onto the PVC piping, Gardena quick release garden hose fixtures
> mated onto the PVC piping so I can easily remove the tubing grid from the
> chamber for cleaning.  I use an ordinary valve to limit the air flow into
> the system, and I also bleed additionnal air leak at the compressor.   
> I've
> found that small pumps were just a tad weak, I prefer to use a stronger
> source and limit the output.
> As soon as I've burned some boards I'll post pics of the assembly.
> Robert

I'll bet most of us have done dry transfers at some time. It would be  
a good product if your choice of patterns could be made on a printer.  
Instead of buying arrays of lines and dots made by someone else,  
there would be your own PCB layout made by yourself, ready to rub on  
the board. The people who make dry transfers have to come up with a  
way to make the blank material available to us.

On Tue, 24 May 2005 09:52:23 -0700, Terry Mickelson <tmdslca@...>  
wrote:

> I'll bet most of us have done dry transfers at some time. It would be
> a good product if your choice of patterns could be made on a printer.
> Instead of buying arrays of lines and dots made by someone else,
> there would be your own PCB layout made by yourself, ready to rub on
> the board. The people who make dry transfers have to come up with a
> way to make the blank material available to us.


well, i guess the hardest part is getting the right kind of plastic "ink"  
(i guess toner is close), and also getting the sticky surface on it.

Toner transfer is very similar, more reliable, and cheaper, so i don't  
really see the need.

But it could be nice for front panels, maybe.

ST

.......................
Toner transfer is very similar, more reliable, and cheaper, so i don't
really see the need..........................

It isn't so reliable for me so I'm looking for alternatives.
Terry

On Tue, 24 May 2005 10:43:27 -0700, Terry Mickelson <tmdslca@...>  
wrote:

> .......................
> Toner transfer is very similar, more reliable, and cheaper, so i don't
> really see the need..........................
> It isn't so reliable for me so I'm looking for alternatives.
> Terry


I see.

Well, your chances of getting TT reliable are very high, while the chances  
of getting custom dry transfer decals are quite low...
What problems do you see with TT, maybe we can work them out?


ST

Stefan Trethan wrote:
> Toner transfer is very similar, more reliable, and cheaper, so i don't  
> really see the need.
> 
> But it could be nice for front panels, maybe.

Just curious if anyone has experimented with toner
colors other than black for the above purpose or
for legend "silkscreen" printing?


-- 
uhmgawa@...        www.gnu.org

On Tue, 24 May 2005 13:57:23 -0400, uhmgawa <uhmgawa@...> wrote:

>
> Just curious if anyone has experimented with toner
> colors other than black for the above purpose or
> for legend "silkscreen" printing?


curious here too... very curious..

ST

On May 24, 2005, at 10:47 AM, Stefan Trethan wrote:
> .......................

I see.

Well, your chances of getting TT reliable are very high, while the  
chances
of getting custom dry transfer decals are quite low...
What problems do you see with TT, maybe we can work them out?


ST

Firstly, I have a hot press and with some picture papers, 275 degrees  
at 3 to 5 minutes seems to work reasonably well. Double sided boards  
are a problem to do because of the need to do both sides at once. A  
piece of double sided PC board is placed on the heat press's pad.  
Next is a sheet of paper, then artwork, board, artwork, sheet of  
paper, top of heat press. It works but the results are uneven and not  
repeatable. The major problem is a clean board and I've tried  
everything except paint thinner, which is next. In the meantime a UV  
box was built but I haven't decided on a printer yet. Maybe an Epson  
C86 ? I just don't know.
T

On Tue, 24 May 2005 13:37:47 -0700, Terry Mickelson <tmdslca@...>  
wrote:

>
> Firstly, I have a hot press and with some picture papers, 275 degrees
> at 3 to 5 minutes seems to work reasonably well. Double sided boards
> are a problem to do because of the need to do both sides at once. A
> piece of double sided PC board is placed on the heat press's pad.
> Next is a sheet of paper, then artwork, board, artwork, sheet of
> paper, top of heat press. It works but the results are uneven and not
> repeatable. The major problem is a clean board and I've tried
> everything except paint thinner, which is next. In the meantime a UV
> box was built but I haven't decided on a printer yet. Maybe an Epson
> C86 ? I just don't know.
> T


I do believe presses are a problem with unevenness.

Get a old fuser unit or a laminator, it works well.
Maybe some soft material in the press under the board might help enough.

cleaning the board: sand with 600 or 1000 grit paper, just enough to get  
sanding marks everywhere. then wipe twice with alcohol or acetone and a  
paper tissue, done.

ST

Has any one tried TT by using the backer sheets from lables? As a 
quick experimant last night I printed onto the back sheet of an Avery 
Mailing lable sheet (lables had been removed) the printer printed 
onto the sheet, then ironed it on to a circuit board, and removed the 
sheet while the image was still hot. The image transfered just fine 
and the sheet looks to be resusable.

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
> On Tue, 24 May 2005 13:37:47 -0700, Terry Mickelson <tmdslca@t...>  
> wrote:
> 
> >
> > Firstly, I have a hot press and with some picture papers, 275 
degrees
> > at 3 to 5 minutes seems to work reasonably well. Double sided 
boards
> > are a problem to do because of the need to do both sides at once. 
A
> > piece of double sided PC board is placed on the heat press's pad.
> > Next is a sheet of paper, then artwork, board, artwork, sheet of
> > paper, top of heat press. It works but the results are uneven and 
not
> > repeatable. The major problem is a clean board and I've tried
> > everything except paint thinner, which is next. In the meantime a 
UV
> > box was built but I haven't decided on a printer yet. Maybe an 
Epson
> > C86 ? I just don't know.
> > T
> 
> 
> I do believe presses are a problem with unevenness.
> 
> Get a old fuser unit or a laminator, it works well.
> Maybe some soft material in the press under the board might help 
enough.
> 
> cleaning the board: sand with 600 or 1000 grit paper, just enough 
to get  
> sanding marks everywhere. then wipe twice with alcohol or acetone 
and a  

> paper tissue, done.
> 
> ST

Yep, it's back in the archives somewhere. Worth bringing up again.

I seem to recall those who tried had similar experiences. Easy removal
and able to reuse several times.

I saved some label backing sheets but haven't had a chance to try it
for myself.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "idaho_huckleberry"
<dmiller45@j...> wrote:

> Has any one tried TT by using the backer sheets from lables? As a 
> quick experimant last night I printed onto the back sheet of an Avery 
> Mailing lable sheet (lables had been removed) the printer printed 
> onto the sheet, then ironed it on to a circuit board, and removed the 
> sheet while the image was still hot. The image transfered just fine 
> and the sheet looks to be resusable.
>

On Wed, 25 May 2005 18:05:11 +0200, idaho_huckleberry <dmiller45@...>  
wrote:

> Has any one tried TT by using the backer sheets from lables? As a
> quick experimant last night I printed onto the back sheet of an Avery
> Mailing lable sheet (lables had been removed) the printer printed
> onto the sheet, then ironed it on to a circuit board, and removed the
> sheet while the image was still hot. The image transfered just fine
> and the sheet looks to be resusable.


many have tried but most have found the toner does not adhere to the  
paper, and gets brushed off too easy.
Seems to depend a lot on the printer.

ST

You mean something like this?
http://tinyurl.com/djsdf


Regards
James


--- In Homebrew_PCBs@yahoogroups.com, Terry Mickelson <tmdslca@t...> 
wrote:
> I'll bet most of us have done dry transfers at some time. It would 
be  
> a good product if your choice of patterns could be made on a 
printer.  
> Instead of buying arrays of lines and dots made by someone else,  
> there would be your own PCB layout made by yourself, ready to rub
on 
 
> the board. The people who make dry transfers have to come up with a
 
> way to make the blank material available to us.

On Wed, 25 May 2005 20:18:26 +0200, James RM <tvi@...> wrote:

> You mean something like this?
> http://tinyurl.com/djsdf
> Regards
> James


I bet if i can get the right spray glue i can do that with silicone  
paper...
might try...

But as a replacement for TT to copper this is silly, 'cause it requires TT  
in the first place ;-)

ST