Homebrew PCBs

I have just tried ferric chloride for the first time, it seems to etch
faster & better than ammonium persulphate.
Has anyone have simple plans for a spray etcher (only smallish)I would
like to be able to see the boards as they are etching without lifting
them out of the solution and thought if boards were mounted on an
angle a bit less than 90 degrees i could spray stripper from top edge
and still see board.
Any ideas appreciated.
Philip

p.s. my current setup is pyrex dish submersed in aluminium custom pot
sitting on hot plate.

You should try with a pump that has no-metal parts in the impeller. I 
am very impressed why in this forum almost nobody seems interested in 
building a spray etching system. That is the disadvantage of the "home-
brew" point-of-view. When you want to go like the pros, nobody seems 
interested. By the way, with a home-build spray ecthing system I was 
able to etch an 30x30 cm double-sided board in 4 minutes with ferric 
chloride at room temperature, with excelent resolution.

I've been doing PCBs for a good 30 years, perhaps more...

I wonder why one would not use the garden sprayers one can buy from 
Lowes and an aquarium pump?  It would be a balancing act between 
pressure available and spray pattern, but I suspect it could be done.

Adam Seychell wrote:

> jcarlosmor wrote:
>   
>> You should try with a pump that has no-metal parts in the impeller. I
>> am very impressed why in this forum almost nobody seems interested in
>> building a spray etching system. That is the disadvantage of the "home-
>> brew" point-of-view. When you want to go like the pros, nobody seems
>> interested. By the way, with a home-build spray ecthing system I was
>> able to etch an 30x30 cm double-sided board in 4 minutes with ferric
>> chloride at room temperature, with excelent resolution.
>>
>>     
>
> I built a spray etcher, admittedly it was a very substantial hobby 
> project. It was about 3 years ago when I had my first attempt. You need 
> tools like a lathe to fabricate pulley and other rotational parts, and a 
> hot air plastic welder to make the tanks. There is lots of plumbing 
> involved, hoses, brackets, and depending on how you do the spray arm 
> oscillations, you need electronics for control. Learning how to prevent 
> corrosion and leaks was another big challenge for me.
>
> I use two paralleled modified 12 volt Shurflo diaphragm pumps, giving 
> approximately 2.5 bar at 14L/minute total into 4 fan nozzles positioned 
> on opposite sides of the PCB. It is a double sided spray etcher, with 
> PCB located vertically at the center of tank. The tank lid has a spray 
> proof slot for the PCB to enter.
>
> Before anyone comments on the excessive effort in designing and building 
> ones own spray etcher for the purpose of homebrew PCBs, I'll say its 
> ultimately just part of a hobby and much like any home project.
>
> Adam
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
>
>
>
>

jcarlosmor wrote:
> 
> 
> You should try with a pump that has no-metal parts in the impeller. I
> am very impressed why in this forum almost nobody seems interested in
> building a spray etching system. That is the disadvantage of the "home-
> brew" point-of-view. When you want to go like the pros, nobody seems
> interested. By the way, with a home-build spray ecthing system I was
> able to etch an 30x30 cm double-sided board in 4 minutes with ferric
> chloride at room temperature, with excelent resolution.
> 

I built a spray etcher, admittedly it was a very substantial hobby 
project. It was about 3 years ago when I had my first attempt. You need 
tools like a lathe to fabricate pulley and other rotational parts, and a 
hot air plastic welder to make the tanks. There is lots of plumbing 
involved, hoses, brackets, and depending on how you do the spray arm 
oscillations, you need electronics for control. Learning how to prevent 
corrosion and leaks was another big challenge for me.

I use two paralleled modified 12 volt Shurflo diaphragm pumps, giving 
approximately 2.5 bar at 14L/minute total into 4 fan nozzles positioned 
on opposite sides of the PCB. It is a double sided spray etcher, with 
PCB located vertically at the center of tank. The tank lid has a spray 
proof slot for the PCB to enter.

Before anyone comments on the excessive effort in designing and building 
ones own spray etcher for the purpose of homebrew PCBs, I'll say its 
ultimately just part of a hobby and much like any home project.

Adam

Maybe I'm a little out of sync with the conversation, but my first 
thoughts involve air and suction. like a siphon feed on paint guns and 
sand blasters. a valve to control air flow, two plastic pipe joining at 
a slight angle to form the suction. a tip for the spray pattern. Sort 
of a large version of the cheap plastic model car airbrushes.
Any thoughts?

Adam Seychell <a_seychell@...> wrote:

> Before anyone comments on the excessive effort in designing and
building 
> ones own spray etcher for the purpose of homebrew PCBs, I'll say its 
> ultimately just part of a hobby and much like any home project.
> 
> Adam
>
I am not interested in knocking anyones design, I have a lathe, mill &
most other tools needed to construct hobby stuff.
I am interested if anyone has photos or links or parts lists, I'm in
Tasmania so no doubtedly I may not be able to get parts from the other
side of the world.
I am prepared to make an etch tank for hobby use that may get used
from 1 time per month to many times per week.
My preferred size board to fit would be no bigger than 200 x 300 mm as
that is the biggest board that will fit in my exposure unit.
Philip

James McGee wrote:
> 
> 
> Maybe I'm a little out of sync with the conversation, but my first
> thoughts involve air and suction. like a siphon feed on paint guns and
> sand blasters. a valve to control air flow, two plastic pipe joining at
> a slight angle to form the suction. a tip for the spray pattern. Sort
> of a large version of the cheap plastic model car airbrushes.
> Any thoughts?
> 

You might have a few ventilation problems. Remember , your not spraying 
water on the garden. Such volume of air will force very undesirable 
amounts of etchant mist out of the spray chamber. The etchant must be 
contained. I'm not even going to ask if you were thinking of spraying 
out in the open.

Adam

you dont need spray etcher to make such boards.
  it is much easier to make tank that uses foam .
  you need tank (with angled board inside) , low pressure pump, simple bubbler and few litres of fecl .. and an (domestic) additive to make good fecl bubbles :)

electrophilip <electrophil@...> wrote:
          Adam Seychell <a_seychell@...> wrote:

> Before anyone comments on the excessive effort in designing and
building 
> ones own spray etcher for the purpose of homebrew PCBs, I'll say its 
> ultimately just part of a hobby and much like any home project.
> 
> Adam
>
I am not interested in knocking anyones design, I have a lathe, mill &
most other tools needed to construct hobby stuff.
I am interested if anyone has photos or links or parts lists, I'm in
Tasmania so no doubtedly I may not be able to get parts from the other
side of the world.
I am prepared to make an etch tank for hobby use that may get used
from 1 time per month to many times per week.
My preferred size board to fit would be no bigger than 200 x 300 mm as
that is the biggest board that will fit in my exposure unit.
Philip



         

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

Snip
> That is the disadvantage of the "home-
> brew" point-of-view. When you want to go like the pros, nobody seems 
> interested. By the way, with a home-build spray ecthing system I was 
> able to etch an 30x30 cm double-sided board in 4 minutes with ferric 
> chloride at room temperature, with excelent resolution.

Most Home-brew-ers like to KISS or Keep It Simple Sam. A simple bubble 
etch tank with an aquarium tank air pump using a 300ml etch solution of 
1 part ~30% HCl and 2 parts 3% H2O2 can etch a 6" * 9" board in about 3 
minutes. This set up involves no heating of the chemicals, no pumps, no 
electronics to control the spray nozzel pattern, and no spray mist. 
This set up provides crisp lines, with out the mess. Sure a spray tank 
is nice for production runs with multiple boards at a time, but as a 
home-brew-er KISS works for most.

On Sat, 21 Apr 2007 22:15:16 +0200, jcarlosmor <jcarlosmor@...>  
wrote:

> I
> am very impressed why in this forum almost nobody seems interested in
> building a spray etching system. That is the disadvantage of the "home-
> brew" point-of-view. When you want to go like the pros, nobody seems
> interested. By the way, with a home-build spray ecthing system I was
> able to etch an 30x30 cm double-sided board in 4 minutes with ferric
> chloride at room temperature, with excelent resolution.


The reason is it's old news, several of us have been there, done that,  
tried that, and few are eager to go over it all again.

Look in the archives, virtually any form of spray etcher one can envision  
has been tried or used or at least discussed at great length.

Suggest a topology, and i tell you roughly what was done about it since i  
joined.

I personally tried making a rotary spray etcher, but it was way too much  
noise and hassle for what it did. At the moment i think the setup with a  
sureflow or flowjet membrane pump and either stationary or moving nozzles,  
as some already use, would be the most reasonable. But still expensive and  
complicated.

ST

Sorry, I figured everyone had taken care of their ventilation 
problems. I cant etch without proper ventilation, I want to 
live ........... one breath of the stuff and I went to work outside.
That stuff WILL kill you. My suggestion is First take care of the 
ventilation before you etch another board with any process.



 --- In Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@...> 
wrote:
>
> James McGee wrote:
> > 
> > 
> > Maybe I'm a little out of sync with the conversation, but my first
> > thoughts involve air and suction. like a siphon feed on paint 
guns and
> > sand blasters. a valve to control air flow, two plastic pipe 
joining at
> > a slight angle to form the suction. a tip for the spray pattern. 
Sort
> > of a large version of the cheap plastic model car airbrushes.
> > Any thoughts?
> > 
> 
> You might have a few ventilation problems. Remember , your not 
spraying 
> water on the garden. Such volume of air will force very undesirable 
> amounts of etchant mist out of the spray chamber. The etchant must 
be 
> contained. I'm not even going to ask if you were thinking of 
spraying 

> out in the open.
> 
> Adam
>

On Sun, 22 Apr 2007 10:08:00 +0200, James McGee <ace@...> wrote:

> Sorry, I figured everyone had taken care of their ventilation
> problems. I cant etch without proper ventilation, I want to
> live ........... one breath of the stuff and I went to work outside.
> That stuff WILL kill you. My suggestion is First take care of the
> ventilation before you etch another board with any process.


CuCl of reasonable strength in a bubble etcher is no problem at all,  
indoors with no additional ventilation.
Neither is FeCl i would presume.

I used to run the bubbler closed loop, but the mist made the valves in the  
air pump stick (maybe it would've worked better had i added mist trap).  
But even with the open loop air there is minimal smell and no irritating  
fumes.

ST

guja wrote:
> you dont need spray etcher to make such boards.
>   it is much easier to make tank that uses foam .
>   you need tank (with angled board inside) , low pressure pump, simple bubbler and few litres of fecl .. and an (domestic) additive to make good fecl bubbles :)

Bubble and foam etchers are a very gentle agitation and etch everything
off in most cases. Many times however, traces of copper are left because
of stubborn resist caused by variations in pcb cleaning, coating, and age
of chemicals used.

A spray etcher with proper nozzles has a *very* hard fluid impact compared
to bubble etchers and really knocks off the last few percent of stubborn
cases.

> electrophilip <electrophil@...> wrote:
>           Adam Seychell <a_seychell@...> wrote:
> 
>> Before anyone comments on the excessive effort in designing and
> building 
>> ones own spray etcher for the purpose of homebrew PCBs, I'll say its 
>> ultimately just part of a hobby and much like any home project.
>>
>> Adam
>>
> I am not interested in knocking anyones design, I have a lathe, mill &
> most other tools needed to construct hobby stuff.
> I am interested if anyone has photos or links or parts lists, I'm in
> Tasmania so no doubtedly I may not be able to get parts from the other
> side of the world.
> I am prepared to make an etch tank for hobby use that may get used
> from 1 time per month to many times per week.
> My preferred size board to fit would be no bigger than 200 x 300 mm as
> that is the biggest board that will fit in my exposure unit.
> Philip

On Sun, 22 Apr 2007 14:00:30 +0200, Russell Shaw <rjshaw@...>  
wrote:

> Bubble and foam etchers are a very gentle agitation and etch everything
> off in most cases. Many times however, traces of copper are left because
> of stubborn resist caused by variations in pcb cleaning, coating, and age
> of chemicals used.
> A spray etcher with proper nozzles has a *very* hard fluid impact  
> compared
> to bubble etchers and really knocks off the last few percent of stubborn
> cases.

Maybe including the resist we want, considering many of us use  
less-than-industrial-strength resist.

ST

guja wrote:
> 
> 
> you dont need spray etcher to make such boards.
> it is much easier to make tank that uses foam .
> you need tank (with angled board inside) , low pressure pump, simple 
> bubbler and few litres of fecl .. and an (domestic) additive to make 
> good fecl bubbles :)
> 

Spray etching has the advantage of etching more downward and less 
sideways. There is no other way of achieving that with non-spray etch. 
Gravity can't help you either because insoluble film formed by FeCl3 or 
CuCl2 etching at the copper surface does not fall uniformly or 
predictably in a stagnate solution.

Still, I do not think its worth while a hobbyist building a spray etcher 
  in order to improve etch factor.

Adam