Yahoo Groups archive

Homebrew_PCBs

Index last updated: 2026-03-31 13:47 UTC

Thread

copper plating

copper plating

2003-11-17 by roel_cnc

Hi,

I'm trying to get me bath plating but it isnt working as it should be!
only thing i got is a dark brown easely wipe of film
pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
also tryt a 5 volt make same result only faster
have to tell the bath solution is made as adam's style with a
terracotta pot - acid is pritty blue

gr. Roel

Re: [Homebrew_PCBs] copper plating

2003-11-18 by Adam Seychell

Cathode current density (C.D.) normally between 10 ~ 20 mA/sq.cm.
Are you getting hydrogen from the PCB ?
If so then C.D. is too high or copper too low.

To check approx. copper sulfate concentration make up a test
solution of your desired concentration (e.g. 80 g/L CuSO4.5H20)
and put it in a test tube. Then take sample of plating solution
and put into a identical test tube and fill to equal height. Look
though the end of each test tube and compare the color.
This will get you +-20% accuracy which can be good enough.



roel_cnc wrote:
> Hi,
>
> I'm trying to get me bath plating but it isnt working as it should be!
> only thing i got is a dark brown easely wipe of film
> pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
> also tryt a 5 volt make same result only faster
> have to tell the bath solution is made as adam's style with a
> terracotta pot - acid is pritty blue
>
> gr. Roel
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: [Homebrew_PCBs] copper plating

2003-11-18 by mpdickens

I'm no expert at electroplating, but it sounds to me
like you have the pcb is connected to the annode (And
it should be connected to the cathode). In other
words, you have your electrodes reversed.


Best regards

Marvin Dickens

> > I'm trying to get me bath plating but it isnt
> working as it should be!
> > only thing i got is a dark brown easely wipe of
> film


=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Protect your identity with Yahoo! Mail AddressGuard
http://antispam.yahoo.com/whatsnewfree

Re: copper plating

2003-11-18 by twb8899

You probably need to add some brightner to this bath. The brown film
being deposited is called "burning" and is the result of low
brightner, high current density or both.

Most acid copper baths can operate around 30 amps per square foot
with the proper bightner additions. The voltage will be approximately
1.5 volts but can vary depending on the acid content. Do some
research on the "Hull Cell" which is a miniature plating tank with a
diagonal cathode. This small plating cell can be used to trouble
shoot most plating baths. It will show the high and low current
density areas and help determine the proper brightner levels.

A regulated power supply may not be the best way to make a rectifier.
I have always used a "variac" variable transformer controlled
rectifier for plating. This allows to current to be set without the
power supply trying to compensate. The voltage will end up where it
needs to be if the current is set properly. You could try using a
model train transformer for your rectifier or use a triac lamp dimmer
to control the power supply transformer. Maybe some of these ideas
will help.

Tom

--- In Homebrew_PCBs@yahoogroups.com, "roel_cnc" <atmelletje@g...>
wrote:
> Hi,
>
> I'm trying to get me bath plating but it isnt working as it should
be!
> only thing i got is a dark brown easely wipe of film
> pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
> also tryt a 5 volt make same result only faster
> have to tell the bath solution is made as adam's style with a
> terracotta pot - acid is pritty blue
>
> gr. Roel

Re: copper plating

2003-11-18 by twb8899

You probably need to add some brightner to this bath. The brown film
being deposited is called "burning" and is the result of low
brightner, high current density or both.

Most acid copper baths can operate around 30 amps per square foot
with the proper bightner additions. The voltage will be approximately
1.5 volts but can vary depending on the acid content. Do some
research on the "Hull Cell" which is a miniature plating tank with a
diagonal cathode. This small plating cell can be used to trouble
shoot most plating baths. It will show the high and low current
density areas and help determine the proper brightner levels.

A regulated power supply may not be the best way to make a rectifier.
I have always used a "variac" variable transformer controlled
rectifier for plating. This allows to current to be set without the
power supply trying to compensate. The voltage will end up where it
needs to be if the current is set properly. You could try using a
model train transformer for your rectifier or use a triac lamp dimmer
to control the power supply transformer. Maybe some of these ideas
will help.

Tom

--- In Homebrew_PCBs@yahoogroups.com, "roel_cnc" <atmelletje@g...>
wrote:
> Hi,
>
> I'm trying to get me bath plating but it isnt working as it should
be!
> only thing i got is a dark brown easely wipe of film
> pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
> also tryt a 5 volt make same result only faster
> have to tell the bath solution is made as adam's style with a
> terracotta pot - acid is pritty blue
>
> gr. Roel

Re: copper plating

2003-11-18 by roel_cnc

--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
<adam_seychell@y...> wrote:
> Cathode current density (C.D.) normally between 10 ~ 20 mA/sq.cm.
> Are you getting hydrogen from the PCB ?

YES got real tiny bubbles also if i change amps as u describe it

> If so then C.D. is too high or copper too low.

the copper must be to low then.
can i do the same thing again with the terra cotta pot (if needed)
with the same solution.

> To check approx. copper sulfate concentration make up a test
> solution of your desired concentration (e.g. 80 g/L CuSO4.5H20)
> and put it in a test tube. Then take sample of plating solution
> and put into a identical test tube and fill to equal height. Look
> though the end of each test tube and compare the color.
> This will get you +-20% accuracy which can be good enough.
>
>
>
> roel_cnc wrote:
> > Hi,
> >
> > I'm trying to get me bath plating but it isnt working as it
should be!
> > only thing i got is a dark brown easely wipe of film
> > pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
> > also tryt a 5 volt make same result only faster
> > have to tell the bath solution is made as adam's style with a
> > terracotta pot - acid is pritty blue
> >
> > gr. Roel
> >
> >
> >
> >
> > Be sure to visit the group home and check for new Bookmarks and
files:
> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> > To unsubscribe from this group, send an email to:
> > Homebrew_PCBs-unsubscribe@yahoogroups.com
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >

Re: [Homebrew_PCBs] Re: copper plating

2003-11-19 by Adam Seychell

roel_cnc wrote:
> --- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
> <adam_seychell@y...> wrote:
>
>>Cathode current density (C.D.) normally between 10 ~ 20 mA/sq.cm.
>>Are you getting hydrogen from the PCB ?
>
>
> YES got real tiny bubbles also if i change amps as u describe it

In that case you plated amorphous copper, which is like copper
metal mud or sponge.

>
>>If so then C.D. is too high or copper too low.
>
>
> the copper must be to low then.
Also don't forget to keep an eye on the current density !!.

As Tom pointed out these copper baths can operate at 30A/ft^2
(30mA/cm^2), but it depends on the solutions agitation and
brightener. You can be safe at 10mA/cm^2 without brightener. I
run at 20mA/cm^2 with air bubble agitation and use brightener.
Tom made a very good point about the "Hull cell". One of these
are essential for testing the performance of your plating solution.

> can i do the same thing again with the terra cotta pot (if needed)
> with the same solution.
Of course, just put the pot back and continue generating copper
sulfate for as long as you want, when you want.
I'd get some copper sulfate pentahydrate crystals from the garden
store and make up a known solution so you can compare colors and
thus have some idea of the copper concentration in your plating bath.

>
>>To check approx. copper sulfate concentration make up a test
>>solution of your desired concentration (e.g. 80 g/L CuSO4.5H20)
>>and put it in a test tube. Then take sample of plating solution
>>and put into a identical test tube and fill to equal height. Look
>>though the end of each test tube and compare the color.
>>This will get you +-20% accuracy which can be good enough.
>>
>>
>>
>>roel_cnc wrote:
>>
>>>Hi,
>>>
>>>I'm trying to get me bath plating but it isnt working as it
>
> should be!
>
>>>only thing i got is a dark brown easely wipe of film
>>>pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
>>>also tryt a 5 volt make same result only faster
>>>have to tell the bath solution is made as adam's style with a
>>>terracotta pot - acid is pritty blue
>>>
>>>gr. Roel
>>>
>>>
>>>
>>>
>>>Be sure to visit the group home and check for new Bookmarks and
>
> files:
>
>>>http://groups.yahoo.com/group/Homebrew_PCBs
>>>
>>>To unsubscribe from this group, send an email to:
>>>Homebrew_PCBs-unsubscribe@yahoogroups.com
>>>
>>>
>>>
>>>Your use of Yahoo! Groups is subject to
>
> http://docs.yahoo.com/info/terms/
>
>>>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: copper plating

2003-11-19 by Steve

Around here, a search of thrift stores turns up quite a few model
train transformers and slot car tranformers, at very cheap prices.

Not all light dimmers will handle a transformer as a load and may blow
out. If the transformer is at too high a voltage, you can ease both
problems by putting an incandescent light bulb in series with the
primary and attach this to the light dimmer.

Steve

--- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@y...> wrote:
...
> A regulated power supply may not be the best way to make a rectifier.
> I have always used a "variac" variable transformer controlled
> rectifier for plating. This allows to current to be set without the
> power supply trying to compensate. The voltage will end up where it
> needs to be if the current is set properly. You could try using a
> model train transformer for your rectifier or use a triac lamp dimmer
> to control the power supply transformer. Maybe some of these ideas
> will help.

Re: [Homebrew_PCBs] Re: copper plating

2003-11-19 by Stefan Trethan

On Wed, 19 Nov 2003 03:06:24 -0000, Steve <alienrelics@...> wrote:

> Around here, a search of thrift stores turns up quite a few model
> train transformers and slot car tranformers, at very cheap prices.
>
> Not all light dimmers will handle a transformer as a load and may blow
> out. If the transformer is at too high a voltage, you can ease both
> problems by putting an incandescent light bulb in series with the
> primary and attach this to the light dimmer.
>
> Steve

I found out that variac transformers are really cheap at ebay.
while 100VA joke size costs 150eur at mailorder shops
the 1200VA variac i got for some 15 eur or so from ebay...

Please keep in mind that most variacs don't have a isolated output.
(So you may want to use a isolation transformer)
But normally you will use a stepdown transformer in any case to reduce
voltage and increase current. So this is not a problem.

Sure a variac doesn't substitute a regulated dc supply.
But for AC or rough rectified DC with loads of A is is just great. Also for
repairs and so the variac with isolation transformer is very convenient.
(safer, no scope ground trouble, you can slowly increase the voltage while
testing something).

It is also good for over-and undervoltage failure testing.

Not exactly on topic - but a good piece of equipment which should be
recommended...

ST

[Homebrew_PCBs] toner iron on - news - success

2003-11-19 by Stefan Trethan

Well, it is maybe hard to admit but i am a stupid git.

Toner transfer works MUCH better if you use the right side of the paper ;-)
.


Somehow on my first test i must have determined the coated side of the
paper wrong.
I printed on the normal paper back side...


Today in bright daylight i saw, more by good luck than on purpose, that the
paper sides have different colors.
one is brighter, the other is slightly yellow.

I thought the bright side must be for printing on then, and then i tried to
remeber if this was the side
i used in my first test after purchasing the paper.


I couldn't be sure that i used the paper right so i decided to do another
test.

The new toner i bought on ebay (original HP) is on its shipping way by now,
i still used the old rebuilt one i had.

Also i wanted to use the laminator, (fuser assembly from copier), but
couldn't get myself
to hook it up and adjust the temperature so i used the old clothes iron
once again.


I just printed on the paper (right side this time), then put it on the
fresh cleaned pcb (thinner to remove toner from previous experiments,
finest sand paper, alcohol last cleaning to remove dust and oils)

and pressed the hot iron on it. i kept a constant, not too hard pressure
for ~30 seconds,
then started to rotate the iron on the pcb (back and forth, my hand doesn't
support 380°)
, keeping pressure all the time for another 30 seconds.

after that i put the hot pcb (with pliers) in a plastic container with a
solution of warm water, dish cleaning detergent and some NaOH (leftover of
the last toner transfer experiment).
Because the pcb was hot the paper immediately got soaked with water
(probably the last time
also the coating on the upper side preventet soaking).

After only a minute i started to rub and peel and discovered a perfect
result.

On one spot i was too eager and scratched the toner off with the finger
nail but the
rest is just amazing!


The image is sharp, no pinholes etc.

Looks just like printed directly on the pcb.



You see - this was a pretty fast experiment (maybe 10 minutes) and it was a
success.
I didn't care much, didn't expect it to work and it prooved me wrong.



I discovered that my current toner leaves pinholes if i don't set to
darkest.
This is not really a problem and the genuine toner is known to be better.



For now this is enough text to read, i will stop it here with a very
important thing:

THANKS EVERYONE FOR HELPING!


At the weekend i will make some pcbs which are in the queue for some time
already.
Maybe there will be scans then in the photo section.

kind regards

Stefan

Pump for sray etching

2003-11-19 by mpdickens

Does anyone on the list have a specific pump
(Manufacturer and part number) that they can recommend
for spray etching? It would be most helpful if the
recommendation was based on personal experience.


Best regards


Marvin Dickens
Alpharetta, Georgia USA

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Protect your identity with Yahoo! Mail AddressGuard
http://antispam.yahoo.com/whatsnewfree

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-20 by Adam Seychell

It just so happens my current project is building a spray
etcher. I asked this same question on this group a month or
two ago and since then I done some research on spray
etching. The pressure should be at least 1 bar for the
nozzles to be effective. I looked for several weeks for a
suitable pump. The magnetic drive centrifuge pumps may seem
ideal for pumping etchant however the smaller and more
affordable pumps of this type do not deliver the required
pressures.

The pump I recommend is a 12V electric diaphragm pump used
for pumping water in recreational vehicles.
The two main manufactures of small 12V electric diaphragm
pumps are Shurflo and Flojet.
Two models were available in my city for reasonable price.
FLojet "Quad II Diaphragm" 4406 series
Shurflo "Aqua King Premier" 2088-422-144

I contacted both manufactures to check for chemical
compatibility, and both replied listing the wetted
materials. Both manufactures used same materials for each
component.

Housing: glass filled polypropylene
Valves: EPDM
Diaphragm: Santoprene

All these materials are compatible with chemicals found in
common etchants.

I bought the Shurflo 2088-422-144 because it was slightly
higher pressure and Shurflo have more data on their pumps.
I have bench tested the pump and found the pump can happily
deliver 180 kPa at 6.1 liters/minute with 12.1 volts at 5.5
amps.
I found the motor will not run for more than 20 ~ 30 minutes
continuously due to thermal cutout protection. Some
cooling of the motor housing would be necessary for it to
run longer. Check out the Shurflo 2088-343-135 for better
performance.




Hope this helps

Adam


mpdickens wrote:
> Does anyone on the list have a specific pump
> (Manufacturer and part number) that they can recommend
> for spray etching? It would be most helpful if the
> recommendation was based on personal experience.
>
>
> Best regards
>
>
> Marvin Dickens
> Alpharetta, Georgia USA
>
> =====
> Registered Linux User No. 80253
> If you use linux, get counted at:
> http://www.linuxcounter.org
>
> __________________________________
> Do you Yahoo!?
> Protect your identity with Yahoo! Mail AddressGuard
> http://antispam.yahoo.com/whatsnewfree
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: toner iron on - news - success

2003-11-20 by mycroft2152

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
<stefan_trethan@g...> wrote:
> Well, it is maybe hard to admit but i am a stupid git.
>
> Toner transfer works MUCH better if you use the right side of the
paper ;-)
> .
>
Welcome to the club. I've been using the clay coated paper with good
results for over a year now, and should have known better. The clay
coated paper tends to fill in any pinholes.

Last week, I picked up a small laminator at Odd Lots for $12.99, to
see if it would work. Unfortunately, it didn't work well with the
clay coated paper, but I remembered reading in the files section
about using the backing sheet from pressure sensitive labels. So i
ran thru a test pattern. Didn't work at all. Then realized, I had
printed on the wrong side of the paper. Success! on the next run.

Myc

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-20 by mpdickens

--- Adam Seychell <adam_seychell@...> wrote:
> It just so happens my current project is building a
> spray etcher.

Obviously, I am also building a spray etcher. I
searched through the message archives and I found
references to a couple of pumps (One was even
recommended...). However, upon examination of these
pumps (Using spec sheets published by the manufacturer
or by talking to manufacturer tech support) it became
obvious that they were not suitable due to either the
materials used in thier construction or not enough
pressure (GPH is never the problem). If anyone bought
those pumps, the etchant most definately destroyed the
shafts (Stainless 316) or the impellers (Delrin) or
both.

I have been looking at centerfuge pumps and diaphram
pumps (Just as you have). However, I have not looked
at the Shurflow or flowking lines (Although I'm gonna
take a look based on your recommendations).

I have found one pump that has suitable materials used
in the construction and produces the desired pressure.
However, it's a submersible and I'm not thrilled with
that (So, I'm not going to purchase it...). It was
$36.00 USD at my local hardware store.

Well Adam, it looks like you and I are breaking new
ground (At least for this list).


Best regards


Marvin Dickens
Alpharetta, Georgia USA


=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-21 by Adam Seychell

I'm pretty sure ammonium persulfate is ok, but don't take my word
for it, test a piece to make sure. SS 316 is ok for at least a
week in ammonium persulfate.
Alkaline ammonia etchants are ok with stainless.

Stainless steel is attacked by HCl and ferric chloride.

Sulfuric acid is ok on stainless provided there is lots of air
around. i.e. its ok to have be splashed on or be wetted with
sulfuric (%20). But if immersed in bottom of a tank the SS will
slowly corrode over a few weeks. I use stainless steel above my
copper and tin plating tank that continuously get splashed with
sulfuric acid and they are still shiny after 2 years.


Stefan Trethan wrote:
>
> which etchants don't eat up stainless steel?
>
> I know sulphuric acid shouldn't, how about HCl?
>
> thanks
> st
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-21 by mpdickens

--- Adam Seychell <adam_seychell@...> wrote:
> I'm pretty sure ammonium persulfate is ok, but don't
> take my word
> for it,

Hi Adam,

The compatibility chart that I have does not say that
SS-316 and ammonium persulfate are incompatible, but
SS-316 and ammonium persulfate are listed in this
chart as "Questionable" Whatever that means...


Best regards

Marvin Dickens
Alpharetta, Georgia USA

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-21 by Adam Seychell

mpdickens wrote:
> --- Adam Seychell <adam_seychell@...> wrote:
>
>>It just so happens my current project is building a
>>spray etcher.
>
>
> Obviously, I am also building a spray etcher. I
> searched through the message archives and I found
> references to a couple of pumps (One was even
> recommended...). However, upon examination of these
> pumps (Using spec sheets published by the manufacturer
> or by talking to manufacturer tech support) it became
> obvious that they were not suitable due to either the
> materials used in thier construction or not enough
> pressure (GPH is never the problem). If anyone bought
> those pumps, the etchant most definately destroyed the
> shafts (Stainless 316) or the impellers (Delrin) or
> both.
>
> I have been looking at centerfuge pumps and diaphram
> pumps (Just as you have). However, I have not looked
> at the Shurflow or flowking lines (Although I'm gonna
> take a look based on your recommendations).
>
> I have found one pump that has suitable materials used
> in the construction and produces the desired pressure.
> However, it's a submersible and I'm not thrilled with
> that (So, I'm not going to purchase it...). It was
> $36.00 USD at my local hardware store.
>
> Well Adam, it looks like you and I are breaking new
> ground (At least for this list).
>
>

What you describe is similar to my findings. Centrifuge pumps are
great for high flow rates, but the pressures are relatively low
compared to other pump architectures. Commercial spray machines
use anywhere from 50 to 150 nozzles and so the ratio of flow rate
to pressure is high making centrifuge pumps very suitable. For a
home built etcher using a low nozzles count, the pressures
requirements ideally should be the same as commercial etcher but
the flow rate is a lot lower.
The diaphragm pump is the best choice for home build spray
machine as it can produce suitably high pressure at low flow rate
and is reasonable priced.
The Shurflo 2088-444-142 I mentioned earlier will do 180 kPa at
6.1 L/min (measured with cupric chloride Sp.Gr 1.30).
I plan to use three fan spray nozzles from Spraying Systems Co.

Nozzle part number:

Veejet Kynar HVV-KY
angle=65°
Capacity size=08
thread=1/4 BSPT
price=AUD $10 each

see link
http://service.spray.com/catalog/pdfmet/catalog60BM/kynar_flat_sm_std.pdf


The 65° was chosen because it is apparently the typical angle for
fan nozzles used in commercial PCB etching machines.
The choice of nozzle capacity and number of nozzles was
calculated based on the pump capacity and maximum width of 275 mm
PCB to etch.

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-21 by Leon Heller

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <homebrew_pcbs@yahoogroups.com>
Sent: Thursday, November 20, 2003 9:18 PM
Subject: Re: [Homebrew_PCBs] Pump for sray etching


>
>
> which etchants don't eat up stainless steel?
>
> I know sulphuric acid shouldn't, how about HCl?

HCl does, judging by what happens to my stainless steel kitchen sink. 8-)

How about a peristaltic pump?

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
http://www.geocities.com/leon_heller

[Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by Stefan Trethan

Well, if stainless is no good in HCl,
which Materials would be good for constructing
a PCB holder for a vertical etch tank?


I think carbon reinforced tubes are very strong. (from rc model supply)
Does the HCl attack the carbon fibers? I think it should not be
a problem with epoxy resin (as pcbs are also this material).


How to construct a holder?
It should allow for etching on both sides and the full surface (no clamps
or such stuff)


Any hints appreciated.

thanks

Stefan

Re: [Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by Markus Zingg

>Well, if stainless is no good in HCl,
>which Materials would be good for constructing
>a PCB holder for a vertical etch tank?
>
>
>I think carbon reinforced tubes are very strong. (from rc model supply)
>Does the HCl attack the carbon fibers? I think it should not be
>a problem with epoxy resin (as pcbs are also this material).
>
>
>How to construct a holder?
>It should allow for etching on both sides and the full surface (no clamps
>or such stuff)
>
>
>Any hints appreciated.
>
>thanks
>
>Stefan

Hi Stefan

I created a little "fork" for my through plating station for the same
purpose and I think this could be easily used for etching too. Ok, a
very small part (actually 3 points each ~5 mm x 1mm) of the PCB would
be covered at one of the borders of the PCB.

By putting a "slider" onto the pronges you can have a tight fixature
of the PCB that easily can be aplied and removed. The fork does of
course not have to be made of stainless steel (as I did in my station)
but round plastic profiles should work well too. The trick here is
definately the slider which will compensate quite a bit the otherwise
bending nature of plastic material.

Markus

RE: [Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by Marty Grove

Why not use PVC? It comes in all shapes and sizes (pvc pipe, sheet, solid
rods, etc...), and it can be connected in various ways (glued, welded, and
screwed using compatible material. PVC screws can be found and used).

Marty

-----Original Message-----
From: Stefan Trethan [mailto:stefan_trethan@...]
Sent: Friday, November 21, 2003 10:29 AM
To: homebrew_pcbs@yahoogroups.com
Subject: [Homebrew_PCBs] PCB Holder construction and materials

Well, if stainless is no good in HCl,
which Materials would be good for constructing
a PCB holder for a vertical etch tank?


I think carbon reinforced tubes are very strong. (from rc model supply)
Does the HCl attack the carbon fibers? I think it should not be
a problem with epoxy resin (as pcbs are also this material).


How to construct a holder?
It should allow for etching on both sides and the full surface (no clamps
or such stuff)


Any hints appreciated.

thanks

Stefan


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

To unsubscribe from this group, send an email to:
Homebrew_PCBs-unsubscribe@yahoogroups.com



Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

Re: [Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by Stefan Trethan

thanks for the suggestions.

The fork thingy i can imagine quite well, i thought about that too (but i
don't think fork is the right
word for it.....
But i'm not sure if i really like te idea much.....


PVC is not bad, i agree with that.


I want to describe the holder of a bungard unit i once used:

it consits of two vertical metal rods, maybe 4mm diameter and 30cm long.
between the vertical rods on the bottom is a plastic bar.
this plastic bar is fixed to the rods, on their ends.

On the top of the plastic spar every 50 mm or so is a small metal stub
post,
with a V groove running parallel to the plastic bar.

Another plastic spar is parallel to the bottom bar, with similar metal
posts
which face downwards.
This second bar slides on the vertical metal rods, and is fixed wirh metal
screws in position.

The pcb is put between the two plastic bars and rests in the V-grooves of
the small metal stub posts.


This setup was used in a bungard spray etcher. with ferric cloride.



As it looks no metal is good in HCl (affordable metal i mean).



So my initial thought was to reconstruct the bungard holder i have seen but
using
carbon tubes instead of the vertical metal rods. metal stub posts and
screws replaced by plastic too.


The main problem with this unit was that it was impossible to etch pcbs
smaller than 5cm. (they won't hold).

I don't clearly remember if there was copper left where the v-grooved
holders touched the board.

I wonder if it would be a good idea to make this v-groove the whole length,
or at least at much shorter intervals
to allow tiny pcbs....


Well, you see, I'm quite biased on this topic.

Another issue is agitation - which method would be good to agitate the
holder with the pcb if i won't use air agitation? a small motor oscillating
it somehow?

I know markus you have included this in your plating station - how do you
move your fork?


I'm still very interested in any discussion and further hints.

thanks

ST

Re: [Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by mpdickens

--- Stefan Trethan <stefan_trethan@...> wrote:
> Well, if stainless is no good in HCl,
> which Materials would be good for constructing
> a PCB holder for a vertical etch tank?

Mine are made of lexan (Lexan which is considerably
cheaper than carbon fiber). Further, they are five
years and have not deteriorated at all during this
time. Also, lexan is easy to heat and
bend/machine/drill/glue and etc...

Best regards


Marvin Dickens
Alpharetta, Georgia USA

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by Stefan Trethan

another interesting link:

http://www.electronics.dit.ie/techprocs/p_c_b.htm

Two sections are very interesting:

An electric motor spins a shaft enclosed in a tubular barrel 18 inches long
containing holes perforated on the circumference from top to bottom. The
motor and tube are vertical from the top of the tank so as when switched
on, the motor spins the tube and stirs the solution. The effect is to
suction of the solution into the barrel and to spray the board being
etched.


>> (this is the rotrary sprayer we discussed before)



Tin-plating (optional)

This is done to provide a nice finish and to protect the copper from
oxidization; also soldering will appear neater and will flow better.

A solution made up of fine tin powder mixed with water is poured into a
basin. The copper is cleaned to a shiny finish be rubbing using a rubber
supplied with the kit. The board is placed in the solution for 10 minutes.
The board should then have a silver finish.


>> (What? tin powder in water? how does this work? really?)


st

Re: [Homebrew_PCBs] PCB Holder construction and materials

2003-11-21 by Leon Heller

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <homebrew_pcbs@yahoogroups.com>
Sent: Friday, November 21, 2003 3:28 PM
Subject: [Homebrew_PCBs] PCB Holder construction and materials


> Well, if stainless is no good in HCl,
> which Materials would be good for constructing
> a PCB holder for a vertical etch tank?

Titanium will probably be OK. Some of the commercial tanks use PVC-coated
steel wire.

Leon Heller, G1HSM
Email: aqzf13@...
http://www.geocities.com/leon_heller

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-22 by mpdickens

--- Adam SeSeychelladadameseychellahoo.com.auauwrote:


> FLFLojetQuad II Diaphragm" 4406 series
> ShShurfloAqua King Premier" 2088-422-144

Well, I just purchased a ShShurflo088-422-444 (US
eqequivalent as well as the aluminum heat exchanger
that fits the body of the motor (A perfect fit, I
might add.... I was told that it will Provide
cocontinousse abilities. Motor does not over heat).
The reason I purchased the ShShurflows that I'veveot a
couple friends who are in the RV business and they ALL
stated emphatically that FlFlojetas a poor reputation
(The pumps fail) within the RV industry (The RV
industry here in the USA. I don't know about the rest
of the world...). Further, there is no heat
exchanger/heat sink for the FlFlojetumps (Which could
be why they fail...) The pump cost me $62.95 US
dollars and the aluminum heat exchanger (Heat sink by
any other name) was less than $20.00. I hope the heat
sink works as advertised... I'll let you know.


The specs for this pump are:

Flow rate: 2.8 gpgpm10.6 lplpm
Shut off pressure: pressure: 45 psi (3.1 bar)
Voltage: 13.7 DC
Amperage: 7.0 Max
Housing: Glass filled polypropylene
Valves: EPEPDMDiaphragm:
SaSantopreneWarranty: 2 years



Best regards


Marvin Dickens
AlAlpharettaGeorgia USA.

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-22 by mpdickens

--- Adam Seychell <adam_seychell@...> wrote:


> FLojet "Quad II Diaphragm" 4406 series
> Shurflo "Aqua King Premier" 2088-422-144

Well, I just purchased a Shurflo 2088-422-444 (US
equivilent?) as well as the aluminum heat exchanger
that fits the body of the motor (A perfect fit, I
might add.... I was told that it will Provide
continous use abilities. Motor does not over heat).
The reason I purchased the Shurflow is that I've got a
couple friends who are in the RV business and they ALL
stated emphatically that Flojet has a poor reputation
(The pumps fail) within the RV industry (The RV
industry here in the USA. I don't know about the rest
of the world...). Further, there is no heat
exchanger/heat sink for the Flojet pumps (Which could
be why they fail...) The pump cost me $62.95 US
dollars and the aluminum heat exchanger (Heat sink by
any other name) was less than $20.00. I hope the heat
sink works as advertised... I'll let you know.


The specs for this pump are:

Flow rate: 2.8 gpm (10.6 lpm)
Shut off pressure: pressure: 45 psi (3.1 bar)
Voltage: 13.7 DC
Amperage: 7.0 Max
Housing: Glass filled polypropylene
Valves: EPDM
Diaphragm: Santoprene
Warranty: 2 years



Best regards


Marvin Dickens
Alharetta, Georgia USA.

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-22 by mpdickens

I just completed a 45 minute run of the Shurflow
fitted with the heat exchanger/heat sink. The pump
worked like a champ and never cut out. Therefore, it's
safe to say it was worth the extra $ 20 USD. OTOH, if
I have to run the pump longer than 15 minutes (And at
15 minutes we are talking a board with unrealistic
copper weight), I've done something horribly wrong...

I figure using only 33% of a proven 45 minute run
gives me pleny of room in the event I do sucessive
runs back to back.


Best regards


Marvin Dickens
Alpharetta, Georgia USA

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

[Homebrew_PCBs] toner transfer board worked & strange behavoir of etchant

2003-11-22 by Stefan Trethan

This evening i put the first toner transfer board i made in the etchant, it
worked like expected.

The tracks are a bit rougher than with optical process, and i have some
closed drill holes (not used toothbrush only thumb).

I hope i can get even better results with the new toner (still not here)
because the coat is very
uneven.



The first board was assembled very fast, so i decided to make also a second
one.

The printing and transfer was without much trouble.


For etching i used a very small plastic container, only filled where the
boards
are with maybe 5mm etchant.
The first worked very well, i put very few drops H2O2 in to get things
started (the etchant was reused from previous
boards). The 35u board seemed to take long as i have mostly used 18u in the
past.
But it got ready in normal time, i put it out and put the etchant away (but
left it in the small container
and didn't put it back in the bottle.)

Now, a few hours later i put the second board in the same container with
still the same etchant.
The first minutes all was well, i added again some drops h2o2 because it
looked like it has vanished in the meantime.

(If i put a board in etchant without fresh H2O2 the pcb surface gets dull
brown/red.
if i add H2O2 it instantly gets bright shiny copper colored (almost
yellowish brass colored.

The etchant turns from blue/green a bit more to green if i add H2O2.


But to the problem:
After some minutes on a spot on the board some blue sludge formed.
After a while it had covered the whole board!
I put it out and cleaned it of (it was maybe 1mm blue sludge, soft).
But as i put it in again nothing happens.
The board only gets dull red/brown like if no H2O2 is in!


So, i thought i know that, this needs H2O2....
a few drops more in there.....


It began to sizzle slightly again, BUT it didn't get shiny copper colord
like i wanted!
it did only form green sludge again!

Next thing i tried:
Add a few of the etchant storage bottle.
Result: green sludge dissolved partially, but still not etching much.


Next experiment: Add HCl
Result: etchant turnns from Blue to green again (like i know and like it)
But still not much of etching action here.


As a last try i put again some H2O2 in.
it worked, and completed the etching.




But i really would like to know what was going on there?
Why did it need H2O2 again after adding the HCl?
What happened to the H2O2 from before?


What was the green sludge? Cu2Cl2?

Is it dissolved by HCl?





If i make the etching tank, permanently containing a relatively big amout
of etchant, how much H2O2 do i have to add each time? Depends this amount
of the copper to be removed or the liquid
volume?

I very appreciate the thought of having a permanently ready etching tank,
especially now as the toner
transfer works...
But if that means i have to use some 50x more H2O2 EACH time etching i
don't like the thought any more.
I think the additional HCl is determined by amount of copper etched, it
only is for providing Cl
for the Cl2CU2 to get Cl2Cu again?

But the H2O2, i still don't understand fully what it does.
I know it adds oxygen, to form water? from the H of H+Cl?

But why then do i need it to get the slightly sizzling bubbling action
going?
I mean if it is only for "regeneration" it should still work hours after it
had
worked when i put the last board out?



You see i'm pretty confused now...
But the board finally is ready and i can heat up the soldering iron...


I would really like to understand this finally, especially if it makes
sense to have a big etch tank
ready. (max. pcb size at least 100x160mm, but most time i make only
50mmx50mm pcbs...)
If this will require huge amounts of H2O2.


And i have another question: the gas, forming if it has too much H2O2 (very
light bubbling is all the time).
But if it is too much you can smell the gas, i assume it is Cl gas?
It may too be oxygen but it smells not like it (how smells oxygen? ;-) )
I try to avoid too much H2O2, i think Cl is not healthy.... Why does it
form?

thanks for any help...

st

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-23 by Adam Seychell

I'm glad it worked well for as mine has worked for me.
The 2088-422-444 is identical to the 2088-422-144 pump I
bought. Although in Australia they sell for AUD$140
(USD$88). The heatsink was not available but I'm going to
worry about that later if heat rise is a problem.

Select your nozzles so you get about 2.0 bar pressure out of
the pump. That way you will get good impact from the spray,
yet the pressure is not too high for the pump to overwork.
You did not specify the pressure you ran the test at. These
diaphragm pumps increase current consumption directly with
pressure. What was the voltage and current during your test ?

Adam

mpdickens wrote:
> I just completed a 45 minute run of the Shurflow
> fitted with the heat exchanger/heat sink. The pump
> worked like a champ and never cut out. Therefore, it's
> safe to say it was worth the extra $ 20 USD. OTOH, if
> I have to run the pump longer than 15 minutes (And at
> 15 minutes we are talking a board with unrealistic
> copper weight), I've done something horribly wrong...
>
> I figure using only 33% of a proven 45 minute run
> gives me pleny of room in the event I do sucessive
> runs back to back.
>
>
> Best regards
>
>
> Marvin Dickens
> Alpharetta, Georgia USA
>
> =====
> Registered Linux User No. 80253
> If you use linux, get counted at:
> http://www.linuxcounter.org
>
> __________________________________
> Do you Yahoo!?
> Free Pop-Up Blocker - Get it now
> http://companion.yahoo.com/
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-23 by Adam Seychell

The Shurflo 2088-343-135 data sheet states 8.7 L/min at 2.1 bar.
The Shurflo 2088-422-444 data sheet states 6.4 L/min at 2.1 bar.

I did a google search and found the link below is to a place
selling the 2088-343-135 for US$69. Its cheaper for me to
get dilivery to Australia , since the best price I found in
my city for the Shurflo 2088-343-135 was AUD$240 (US$150).
If I build another spray machine I'll get this pump.

http://www.tropicalshops.com/NTools/SHURflo-12-Volt-3-GPM-On-Demand-Diaphragm-Pump--Model--2088-343-135.htm

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-23 by mpdickens

--- Adam Seychell <adam_seychell@...> wrote:

> What was the voltage and current during
> your test ?

I set the pump up in a configuration I was told was
the most common in an RV (At least, most RV's here in
the US):

12 Volts
5.5 AMPS (The pump is rated up to 7.0 amps)

Question:

What are the dimensions and specifications of the
nozzles that you are using. I've settled on using
quanitity-6 180 degree fan nozzles (Three for the
front of a pcb and three for the back of a pcb.
Further, I think I'm going to use quantity-2,
windshield wiper motors to rotate the nozzles back and
forth. This will afford me multiple speeds of 180
degree back and forth rotation without having to do a
stepper motor. Also, I've found a portable plastic
sink that I'm going to use as the enclosure that
houses the spray machine. I going to build a door that
fits on the top of the sink that will have a lexan
window for viewing. The drain in the bottom of the
sink will be connected to a gasoline can (Firmly
attached, but quickly and easily removable). The
etchant will be pumped from the gasoline can into the
enclosure and then allowed to drain back into a
gasoline can (For easy maintenace). So, basically,
during the etching process, the etchant will circulate
between the gasoline can and the enclosure via the
pump. Modularizing the etchant allows for a couple of
features/benefits:

1.) I can filter the etchant as it etches (Less wear
on the pump) so that viscosity stays realively
constant.

2.) Regenerating etchant and/or changing out etchant
is easy.

3.) I can easily wash the pump out with h20 following
use without diluting/contaiminating the etchant.

4.) I can wash the board in the machine prior to
removal.

5.) breaking down the etching machine is easy: The
etchant is self contained and easily storable.


Best regards


Marvin Dickens

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-23 by Adam Seychell

I mentioned the nozzle types I'm using in one of my earlier
replies.
What you propose sounds interesting. Just a quick warning,
try not spend a lots of money on an idea in case you end up
scraping it and starting again :) I've leaned this the hard
way.
I think one of the most difficult tasks building a spray
etcher is configuring the nozzles and spray patters so you
get uniform etching. I'm sure the spray etching equipment
manufactures spent lots on R+D to get this right.

Adam


mpdickens wrote:

> --- Adam Seychell <adam_seychell@...> wrote:
>
>
>>What was the voltage and current during
>>your test ?
>
>
> I set the pump up in a configuration I was told was
> the most common in an RV (At least, most RV's here in
> the US):
>
> 12 Volts
> 5.5 AMPS (The pump is rated up to 7.0 amps)
>
> Question:
>
> What are the dimensions and specifications of the
> nozzles that you are using. I've settled on using
> quanitity-6 180 degree fan nozzles (Three for the
> front of a pcb and three for the back of a pcb.
> Further, I think I'm going to use quantity-2,
> windshield wiper motors to rotate the nozzles back and
> forth. This will afford me multiple speeds of 180
> degree back and forth rotation without having to do a
> stepper motor. Also, I've found a portable plastic
> sink that I'm going to use as the enclosure that
> houses the spray machine. I going to build a door that
> fits on the top of the sink that will have a lexan
> window for viewing. The drain in the bottom of the
> sink will be connected to a gasoline can (Firmly
> attached, but quickly and easily removable). The
> etchant will be pumped from the gasoline can into the
> enclosure and then allowed to drain back into a
> gasoline can (For easy maintenace). So, basically,
> during the etching process, the etchant will circulate
> between the gasoline can and the enclosure via the
> pump. Modularizing the etchant allows for a couple of
> features/benefits:
>
> 1.) I can filter the etchant as it etches (Less wear
> on the pump) so that viscosity stays realively
> constant.
>
> 2.) Regenerating etchant and/or changing out etchant
> is easy.
>
> 3.) I can easily wash the pump out with h20 following
> use without diluting/contaiminating the etchant.
>
> 4.) I can wash the board in the machine prior to
> removal.
>
> 5.) breaking down the etching machine is easy: The
> etchant is self contained and easily storable.
>
>
> Best regards
>
>
> Marvin Dickens
>
> =====
> Registered Linux User No. 80253
> If you use linux, get counted at:
> http://www.linuxcounter.org
>
> __________________________________
> Do you Yahoo!?
> Free Pop-Up Blocker - Get it now
> http://companion.yahoo.com/
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-24 by mpdickens

--- Adam Seychell <adam_seychell@...> wrote:
> I mentioned the nozzle types I'm using in one of my
> earlier replies.

I'll look back through my emails.


> What you propose sounds interesting.

How are you planning on doing it?

> Just a quick
> warning, try not spend a lots of money on an idea in
case you end up scraping it and starting again :)
I've leaned this the hard way.

I too, have Been there and done that. Expensive, waste
of time and frustrating.

> I think one of the most difficult tasks building a
> spray etcher is configuring the nozzles and spray
> patters so you get uniform etching. I'm sure the
> spray etching equipment manufactures spent lots on
> R+D to get this right.

Funny you say mention this. Ever since I started
thinking about building a spray etcher, I've been
preoccupied with the geometry of the spray patterns
and what nozzle configuration(s) would give optimal
results. This aspect (And the pump) are the heart of
the etcher. Everything else is nothing more than
practicalities (Enclosure and etc...). After quite a
bit of thought, I decided that R&D would be the only
way for me to figure this out unless I had access to a
high quality spray etcher that I could study. Anyway,
I've got a friend who works for Scientific Atlanta in
thier development department. They have a couple of
Bungards as well as some US manufactured machines.
These machines are of various sizes and further, I
understand at least one of the machines has heads and
nozzles that can be reconfigured on the fly (Not that
I would want to, but I'm interested in what the
different geometries are
and why/when they are used. He has arranged for me to
come by and take a look them (Alpharetta is a about a
20 minute ride to Norcross, which is where Scientific
Atlanta is headquartered) this week.

I not going to begin purchasing anything (Other than
the pump I already own) until I understand the
geometry of the sray pattern(s). Once I understand the
geometry, I'll build the spray platters and prototype
the mechanics that are responsible for platter
rotation. Once I've got this down, I'll purchase the
sink, plumbing and whatever else I need. FWIW, I've
already got the interior and exterior dimensions of
the sink, so at least I can't (Well, I suppose I could
if I really f***up...) build platters and mechanics
that will not fit into the sink :) My reasoning behind
using the windshield wiper motors is that these motors
are variable speed, 12 volt, extremely reliable, dirt
cheap ($6.00 each) and come preconfigured for perfect
180 degree motion.

Best

Marvin Dickens
Alpharetta, Georgia USA







=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-24 by mpdickens

Oh yeah, I forgot to mention that the total estimated
cost of this device as currently visioned is $110.00
USD excluding the nozzles, which I think is pretty
good for a quality spray etcher. But, as with most
projects, this number could increase by 20% ( And in
this case, however unlikely, drop by as much as
3%...)unless I royally screw the design up.

As soon as this project is complete, tested and
working, I'll post pictures, a bill of materials and a
few notes.



Best

Marvin Dickens
Alpharetta, Georgia

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-24 by Adam Seychell

mpdickens wrote:

> Oh yeah, I forgot to mention that the total estimated
> cost of this device as currently visioned is $110.00
> USD excluding the nozzles, which I think is pretty
> good for a quality spray etcher. But, as with most
> projects, this number could increase by 20% ( And in
> this case, however unlikely, drop by as much as
> 3%...)unless I royally screw the design up.
>
> As soon as this project is complete, tested and
> working, I'll post pictures, a bill of materials and a
> few notes.
>

Excellent, Will love to see the finished result. But don't rush
it , let it be a rewarding and fun project. The cost will go up
I'm sure, it never goes down :).

I am making a single sided spray etcher. All construction is by
welded PVC sheet (mostly gray 4.5mm) There is a sealed lid and
the PCB enters a raised opening on the lid so the PCB is more or
less horizontal on the "underside" of the lid. A conveyor spray
bar having 3 fan type nozzles mounted to it will move linearly
across the width of the PCB and pray etchant upwards. Below the
spray bar is room for 12 liters of etchant.

some dimensions;

Chamber (internal) 340 x 360 mm, height 330 mm
PCB panel capacity: 210 x 305 mm
nozzle to panel distance: 130 mm (?)
nozzle to nozzle spacing: 110 mm (?)
etchant sump volume: 12 liters


I have finished building the chamber and lid. Today I finished a
building a conveyor mechanism using an idea of pulleys and twine
stretched across the chamber. It doesn't work because of friction
on the plastic shafts and twine is not steady. Now I'm going to
use a different approach (throwing away several days of work on
the old idea). This time I might use two rails mounted inside of
the chamber walls. A spray bar assembly having wheels will run on
these two rails. One rail will be a V type fixing its location
parallel to the rail direction and the other side will be simple
flat rail configuration. If I can make a sealed housing for a
stepper motor then the spray bar assembly will have motor mounted
to it and directly driving one of the wheels. It would make sense
to use a total of three wheels for the spray assembly so there is
always contact with the rails.

Tools I'm mostly using are;

Plastic hot air welder
A router bench
Saw bench
small lathe for machining plastic pulleys

Re: [Homebrew_PCBs] Pump for sray etching

2003-11-26 by mpdickens

Here are a few specifics on the spray etcher I am
building:

Chamber dimensions:

English 20.75" W X 20.25" L X 11.25" H
Metric 518.75mm W X 506.25mm L X 281.25mm H

PCB panel capacity (Max):

English 18.75" H X 18.25" L
Metric 468.75mm H X 456.25mm L

Number of nozzles : 6

Nozzle configuration : 2 X 3 matrix

Nozzle pressure : 2.2 bar

Nozzle spacing: 3" (75mm) Width between nozzles
3" (75mm) Height between nozzles

Nozzle to panel distance: English 9"
Metric 225mm

Etchant sump tank capacity: 5 Gallons (18.95 Liters)

Pump: Surflo 2088-722-444, 2.8 GPM (10.6 LPM)
45 PSI max before cutoff (3.1 bar)
13.7 VDC @ 7.0 Amp (Max)

Motor for sprayer rotation: Ford-Delco F150, 2002 Yr,

windshield

wiper motor (180 Degree
rotation) Pulled
from a totaled vehicle for
$20.00 (10 minutes to pull
and it was easy)

The following specs may (And probably will) change:

1.) Distance of nozzles to PCB
2.) Nozzle spacing
3.) Nozzle pressure

The pump and the WW motor are both running at 12 Vdc
which simplifies power distribution.

Total cost of materials (As of this post) : $117 USD
Total projected cost of materials : $168 USD


Best regards

Marvin Dickens
Alpharetta, Georgia USA

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org

__________________________________
Do you Yahoo!?
Free Pop-Up Blocker - Get it now
http://companion.yahoo.com/