Homebrew_PCBs

I have completed and air sparger described on the Think and Tinker
website. It sits in the Coleman cooler. I drilled a 9/16" hole in the
lid so a piece of 1/4" schedule 80 PVC tubing from the sparger
protrudes about 2 1/2".

I tried using the tire air compressor I purchased on sale from Harbor
Freight as an air source. Here's the one I am using:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=43479

I drilled a 3/16" hole in a piece of 1/4" PVC rod to make a tube about
1 inch long. I glued this into a short piece of 1/4" PVC schedule 80
tubing to make a connector to the air pump. Although the air
connectors supplied with the pump are threaded, the connection is made
mechnically with an expanding rubber seal at the end of the pump air
hose, and the 1/4" tube works just fine without any threads. My Tygon
tubing fits snugly on the 1/4" sched 80 pipe of this fitting, as well
as at the tank end. It can also be readily removed in order to get the
tank top off.

The sparger works just fine, with lots of air bubbles roiling away in
the water. The only potential problem is how long this pump can run
without a break. I assume it's the same kind of pump as an aquarium
pump, though not as quiet.

Anyway I am moving along (finally) and hope to have the etching tank
working within a week.

I am curious how others hold their PCB in the etchant. I have some
1/4" PVC sheet I can use to make some kind of holder but no "aha"
experiences have come to mind yet.

Grant

At 07:12 PM 4/6/03 +0000, grantfair2001 wrote:

>I am curious how others hold their PCB in the etchant. I have some
>1/4" PVC sheet I can use to make some kind of holder but no "aha"
>experiences have come to mind yet.

I'll see if I can verbally describe what I use. I'll also see about
posting pictures in that folder on YahooGroups (later).

3 raw materials used for my PCB holders: 3/16" stainless steel rod
(available from welding and metal supplier outlets), 1/2" thick
polyethylene (I cut up one of those cheap plastic cutting boards from a
Dollar store), nylon 10-32 bolts.

1) Slice the cutting board into 3/4" wide strips.

2) Separate the strips into 2 groups: end pieces and sliders. At this
point, the pieces look the same - there is no difference between them.

3) Drill 2- 7/32" holes into the strips marked as sliders: about 3/8" from
each end. The holes go through the 3/4" dimension. The holes all have to
line up: if you were to slide the stainless steel rod through the holes,
the resulting panel would look almost how it looked before you sliced it up.

4) Drill a 9/64" into the end of each slider to that it meets the hole
drilled through. Thread those holes with a 10-32 tap. If you slide the
stainless steel rod through the hole, you would be able to use a 10-32 bolt
to lock the rod in place.

5) Drill 2- 11/64" holes into the strips marked as end pieces. They must
be in the same location as the holes in the sliders (about 3/8" from each
end). These holes are smaller than the diameter of the stainless rod and
are intended to be press-fit (hammered) onto the rods.

6) Use a router and V-bit to cut a V-groove into both long sides of each
slider and into 1 side only of each end piece. You are grooving the narrow
(1/2") dimension.

7) Cut the stainless steel rod into the length you want. You need 2 pieces
for each holder. Use a grinder or file to round each end to that you can
easily pound the end pieces onto the rods.

8) Assemble the frames! Pound the stainless steel rods into one of the end
pieces, slip 2 sliders onto the rods, then pound another end piece onto the
ends of the rods. Thread nylon 10-32 screws into the locking holes on the
sliders. Done!

dwayne

--
Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 19 years of Engineering Innovation (1984 - 2003)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
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I used an all-plastic clip similar to one of those potato chip bag clips (except smaller). Here is a pic:
http://www.techfreakz.org/cucl2/?slide=7

~Rolan

--- In Homebrew_PCBs@yahoogroups.com, Dwayne Reid <dwayner@p...> wrote:
> At 07:12 PM 4/6/03 +0000, grantfair2001 wrote:
>
> >I am curious how others hold their PCB in the etchant. I have some
> >1/4" PVC sheet I can use to make some kind of holder but no "aha"
> >experiences have come to mind yet.

I tried verticle etch with cucl and it was't even faster near the bubbles
from the bottom that at the top . stainless steel may not last in the
etchant . attach a float to one end of the pcb for vert etch or a
styrofoam block for a horizontal .

Thanks Dwayne - I look forward to pictures; I have the damndest time
converting word descriptions into mental pictures,and I'm tired tonight.

Stainless and nylon do not stand up well to CuCl etchant, I am told.
But I have some 1/4" PVC rod and can tap holes in sheet PVC and thread
the rod if need be. It's also easy to solvent-weld PVC pieces together.
So I think I could use all PVC to make it, once I understand your
design clearly.

Grant

--- In Homebrew_PCBs@yahoogroups.com, Dwayne Reid <dwayner@p...> wrote:
> At 07:12 PM 4/6/03 +0000, grantfair2001 wrote:
>
> >I am curious how others hold their PCB in the etchant. I have some
> >1/4" PVC sheet I can use to make some kind of holder but no "aha"
> >experiences have come to mind yet.
>
> I'll see if I can verbally describe what I use. I'll also see about
> posting pictures in that folder on YahooGroups (later).
>
> 3 raw materials used for my PCB holders: 3/16" stainless steel rod
> (available from welding and metal supplier outlets), 1/2" thick
> polyethylene (I cut up one of those cheap plastic cutting boards from a
> Dollar store), nylon 10-32 bolts.
>
> 1) Slice the cutting board into 3/4" wide strips.
>
> 2) Separate the strips into 2 groups: end pieces and sliders. At this
> point, the pieces look the same - there is no difference between them.
>
> 3) Drill 2- 7/32" holes into the strips marked as sliders: about
3/8" from
> each end. The holes go through the 3/4" dimension. The holes all
have to
> line up: if you were to slide the stainless steel rod through the
holes,
> the resulting panel would look almost how it looked before you
sliced it up.
>
> 4) Drill a 9/64" into the end of each slider to that it meets the hole
> drilled through. Thread those holes with a 10-32 tap. If you slide
the
> stainless steel rod through the hole, you would be able to use a
10-32 bolt
> to lock the rod in place.
>
> 5) Drill 2- 11/64" holes into the strips marked as end pieces. They
must
> be in the same location as the holes in the sliders (about 3/8" from
each
> end). These holes are smaller than the diameter of the stainless
rod and
> are intended to be press-fit (hammered) onto the rods.
>
> 6) Use a router and V-bit to cut a V-groove into both long sides of
each
> slider and into 1 side only of each end piece. You are grooving the
narrow
> (1/2") dimension.
>
> 7) Cut the stainless steel rod into the length you want. You need 2
pieces
> for each holder. Use a grinder or file to round each end to that
you can
> easily pound the end pieces onto the rods.
>
> 8) Assemble the frames! Pound the stainless steel rods into one of
the end
> pieces, slip 2 sliders onto the rods, then pound another end piece
onto the
> ends of the rods. Thread nylon 10-32 screws into the locking holes
on the
> sliders. Done!
>
> dwayne
>
> --
> Dwayne Reid <dwayner@p...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 19 years of Engineering Innovation (1984 - 2003)
> .-. .-. .-. .-. .-. .-. .-. .-. .-. .-
> `-' `-' `-' `-' `-' `-' `-' `-' `-'
> Do NOT send unsolicited commercial email to this email address.
> This message neither grants consent to receive unsolicited
> commercial email nor is intended to solicit commercial email.

Hi Luther - thanks for the simple but good sounding idea. How do you
fasten styrofoam to your PCB? Rubber band? Or...?

Grant

--- In Homebrew_PCBs@yahoogroups.com, luther m stroud <dukes500@j...>
wrote:

> I tried verticle etch with cucl and it was't even faster near the

bubbles

> from the bottom that at the top . stainless steel may not last in the
> etchant . attach a float to one end of the pcb for vert etch or a
> styrofoam block for a horizontal .

Thanks Rolan - simple, inexpensive and effective!

Grant

--- In Homebrew_PCBs@yahoogroups.com, "rolanyang" <rolan@h...> wrote:
> I used an all-plastic clip similar to one of those potato chip bag
clips (except smaller). Here is a pic:
> http://www.techfreakz.org/cucl2/?slide=7
>
> ~Rolan

I prefer that closed cell polyethene foam that is white or pink that
electronic stuff is shipped in and use the plastic tacks from IC tubes
around the board edges to hold it face doun in the etch

if you clip a carbon rod under that clip in contact with the copper clad
it is suppose to etch faster i read in a magazine reader reply

At 09:18 PM 4/14/03 -0700, luther m stroud wrote:

>I tried verticle etch with cucl and it was't even faster near the bubbles
>from the bottom that at the top . stainless steel may not last in the
>etchant .

The PCB holder arrangement I described has been working well for at least
15 years - that is about the age of the holders I described. However, I
use ammonium persulphate catalyzed with sulfuric acid as my etch solution -
clean and effective. My etch tank is welded stainless steel, as is the
immersion heater used to heat the etchant - both of these have been in
regular use for about 20 years. We used to just hang the boards in the
etcher before I made the holders.

Vertical bubble etch is somewhat slower than a spray etcher but there is a
lot less mess and it was cheap to build. This was a very important
consideration back when we built our PCB etch system.

The air source is a very compact blower (something like a vacuum cleaner
motor) obtained from a local surplus outlet (Princess Auto) years ago. The
sparging tubes are drilled PVC - 2 tubes that form a "U" in the bottom of
the tank.

I've been told that the reason bubble etch works so well with ammonium
persulphate is the constant agitation and the continuous addition of oxygen
to the etch solution. We pretty much followed Clyde Coombs PCB Handbook
and it just works.

dwayne

--
Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 19 years of Engineering Innovation (1984 - 2003)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

Dwayne,
Did you find the Ammonium Persulfate to have a short life for production
work? I did not use it because of the life of the mixture. Was just
wondering about your experience with it.
-Mike

----- Original Message -----
From: "Dwayne Reid" <dwayner@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, April 26, 2003 10:49 AM
Subject: Re: [Homebrew_PCBs] Homemade PCB holders for etcher


> At 09:18 PM 4/14/03 -0700, luther m stroud wrote:
> >I tried verticle etch with cucl and it was't even faster near the bubbles
> >from the bottom that at the top . stainless steel may not last in the
> >etchant .
>
> The PCB holder arrangement I described has been working well for at least
> 15 years - that is about the age of the holders I described. However, I
> use ammonium persulphate catalyzed with sulfuric acid as my etch
solution -
> clean and effective. My etch tank is welded stainless steel, as is the
> immersion heater used to heat the etchant - both of these have been in
> regular use for about 20 years. We used to just hang the boards in the
> etcher before I made the holders.
>
> Vertical bubble etch is somewhat slower than a spray etcher but there is a
> lot less mess and it was cheap to build. This was a very important
> consideration back when we built our PCB etch system.
>
> The air source is a very compact blower (something like a vacuum cleaner
> motor) obtained from a local surplus outlet (Princess Auto) years ago.
The
> sparging tubes are drilled PVC - 2 tubes that form a "U" in the bottom of
> the tank.
>
> I've been told that the reason bubble etch works so well with ammonium
> persulphate is the constant agitation and the continuous addition of
oxygen
> to the etch solution. We pretty much followed Clyde Coombs PCB Handbook
> and it just works.
>
> dwayne
>
> --
> Dwayne Reid <dwayner@...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 19 years of Engineering Innovation (1984 - 2003)
> .-. .-. .-. .-. .-. .-. .-. .-. .-. .-
> `-' `-' `-' `-' `-' `-' `-' `-' `-'
> Do NOT send unsolicited commercial email to this email address.
> This message neither grants consent to receive unsolicited
> commercial email nor is intended to solicit commercial email.
>
>
>
> 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/
>
>

At 11:09 AM 4/26/03 -0700, Mike Putnam wrote:

>Dwayne,
>Did you find the Ammonium Persulfate to have a short life for production
>work? I did not use it because of the life of the mixture. Was just
>wondering about your experience with it.
>-Mike

We don't do production, only prototypes. But yes - we found that the shelf
life was short (days, weeks) until we covered (sealed) the etch tank while
we were not using the system. That seemed to let us get several months out
of each batch of etch.

Disposal is a minor pain - we asked our local university to help us deal
with spent etchant in a safe and legal fashion and they came up with a
simple neutralization scheme that works well and is very inexpensive.

I'm definitely interested in alternative etch techniques. I find the
discussion on CuCl fascinating and am wondering if I should consider trying
a batch.

But I've read some concern about CuCl attacking stainless steel and am
hoping that someone can tell me if storing and using CuCl in a stainless
steel tank with a stainless steel immersion heater is practical.

Thanks!

dwayne

--
Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 19 years of Engineering Innovation (1984 - 2003)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

Hi Dwayne:

Cupric chloride will attack stainless steel.

Best regards

Donald Aitken

----- Original Message -----
From: Dwayne Reid
To: Homebrew_PCBs@yahoogroups.com
Sent: Saturday, April 26, 2003 12:54 PM
Subject: Re: [Homebrew_PCBs] Homemade PCB holders for etcher


At 11:09 AM 4/26/03 -0700, Mike Putnam wrote:
>Dwayne,
>Did you find the Ammonium Persulfate to have a short life for production
>work? I did not use it because of the life of the mixture. Was just
>wondering about your experience with it.
>-Mike

We don't do production, only prototypes. But yes - we found that the shelf
life was short (days, weeks) until we covered (sealed) the etch tank while
we were not using the system. That seemed to let us get several months out
of each batch of etch.

Disposal is a minor pain - we asked our local university to help us deal
with spent etchant in a safe and legal fashion and they came up with a
simple neutralization scheme that works well and is very inexpensive.

I'm definitely interested in alternative etch techniques. I find the
discussion on CuCl fascinating and am wondering if I should consider trying
a batch.

But I've read some concern about CuCl attacking stainless steel and am
hoping that someone can tell me if storing and using CuCl in a stainless
steel tank with a stainless steel immersion heater is practical.

Thanks!

dwayne

--
Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 19 years of Engineering Innovation (1984 - 2003)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.


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