"John Jardine." wrote:

Yes. Tracing paper/greaseproof paper seems distinctly better than clear
film. Bit queer, as I'd have thought the 'frosted-glass' finish would have
dispersed the UV light, much the same way as there still being daylight
after the sun has set. Maybe clear OHP film happily allows UV to bounce
around within the film thickness.

We had the same problem making holograms.
The film was temporarily stuck to a glass plate
with a thin layer of naptha. Under certain conditions
the light would bounce around inside the glass like
an optical fiber leaving unwanted tracks on the film.


Last week did some quickie SOT23 to DIL adapters. Samsung ML-2250 laser,
600dpi. Single sheet. Very nice results.
john

"RST Engineering" wrote in
:


Hello Jim

I use a similar setup to make boards all the time and it works
reasonably well. No 8mil tracks tho.

15 mils is easy. 10 mils with some care. Below that, no promises.


The paper is made by Pulsar and is Digi-Key P/N 182-1003-ND. If
you want to try it get the "GreenTRF" film to go with it, P/N
182-1021-ND. The GreenTRF film is just applied over the toner after
it is transfered from the paper and leaves the image on the board
completely sealed with a glossy green finish. I believe the paper
was
about $1 per 8.5x11 sheet and I don't remember how much the
"GreenTRF" cost me, but it wasn't much for an 8in by 15ft piece.

I use the glossy photo basic paper from Staples, or Costco, or Sam's
Club, or whatever branded private label -- it works better than the
"premium" variety photo paper for whatever reason. It all seems to
work the same. The trick is to use copper-brite scouring powder made
specifically for copper and brass along with one of those green dish
scouring pads to clean and microscratch the bejabbers out of the
board
before applying the resist. It also helps to preheat the board for
about 5 minutes at 150F in a toaster oven after cleaning but before
ironing on the resist.


I've been using ammonium persulfate for etchant and just picked up
some peroxide and acid so I can try making my own etchant.

I've used ferric chloride, ammonium persulfate, and muriatic acid -
hydrogen peroxide and I MUCH prefer the muriatic-peroxide
combination.
What I have NOT perfected in the etch process yet is a method of
agitation for the etchant. Right now I'm using an aquarium with an
air pump and a "bubbling stone", but would love to find another
method. Perhaps I'll work on a magnet with shrink sleeving and RTV
to
seal the ends and another magnet on a motor underneath the aquarium
bottom. That seems like a lot of hassle for a simple agitation, but
I
haven't found a better way.



I have a drill stand for my Dremel Moto-tool that was made by
Dremel
that I use for drilling the boards. I use a #10 Opti-Visor and have
no trouble drilling the boards even with my pathetic eyesight. The
etched drill guide holes in the center of the pads really helps
hitting the holes dead center. With just a little care drills will
last until they get dull. As a matter of fact the only time I break
one is when I get careless trying to go too fast.

The school I teach for has a half dozen good PCB drills, so I'm not
yet forced into that corner. I've also got a BIG pcb shop down the
hill a bit, and they throw away carbide drills by the sackful. I've
gotten them to throw a few sacks my way.


Jim



For etchant I find that CuCl2 and HCl work very nice -- and it is
especially advantagous to agitate by bubbling air thru the solution
since not only does it agitate but the oxygen in the air helps
regenerate the CuCl2 in situ. You can continue to bubble air thru it
after the etching is done to completely regenerate the etchant.

The reactions:
Etching: CuCl2 + Cu - 2CuCl
Regenerating: 4(CuCl) + O2 + 4HCl - 4(CuCl2) + 2(H2O)

Dr. G.

I appreciate the information but note that:

a. I cannot send my students/readers down to Home Depot to pick up a pound
of copper chloride along with the muriatic (swimming pool grout etch) acid.

b. Now I've got a couple of gallons of etchant to keep around the lab in a
proper container for the next go-around.

BTW, what is the color of the CuCl2 and the HCl mixed together?

Jim



"Dr. Grok" wrote in message
news:doqfg.11456$ho6.769@trnddc07...


For etchant I find that CuCl2 and HCl work very nice -- and it is
especially advantagous to agitate by bubbling air thru the solution
since not only does it agitate but the oxygen in the air helps
regenerate the CuCl2 in situ. You can continue to bubble air thru it
after the etching is done to completely regenerate the etchant.

The reactions:
Etching: CuCl2 + Cu - 2CuCl
Regenerating: 4(CuCl) + O2 + 4HCl - 4(CuCl2) + 2(H2O)

Dr. G.

On 29 May 2006 01:54:56 -0700, "Leon"
wrote:


Dave Platt wrote:
In article .com,
Leon wrote:

I just flush it down the toilet. I think that ferric chloride is used
for water treatment and I can't see the small amount of copper doing
any harm by the time it has been diluted millions of times. It's only a
litre ot so every six months - it's negligible.

By the time you dump it in this way, you aren't dumping pure ferric
chloride by any means! You're dumping a residual amount of ferric
chloride, plus a bunch of copper chloride.

Small quantities are acceptable, here in the UK.

Leon

A book I read a long time back recommended mixing spent solution with
concrete powder and sending the resulting brick to the dump. Seems like
one of the best ideas I have heard of if you really care about possible
impacts.

RST Engineering wrote:
I appreciate the information but note that:

a. I cannot send my students/readers down to Home Depot to pick up a pound
of copper chloride along with the muriatic (swimming pool grout etch) acid.

b. Now I've got a couple of gallons of etchant to keep around the lab in a
proper container for the next go-around.

BTW, what is the color of the CuCl2 and the HCl mixed together?

If you start off with HCl and H2O2, you get CuCl2. You don't need to
actually buy the stuff, it gradually becomes more concentrated with
use. Some form of chemical titration is needed with CuCl2 to ensure
that the concentration is correct and that it has the right pH.

Leon

On 1 Jun 2006 02:16:48 -0700, "Leon"
wrote:


RST Engineering wrote:
I appreciate the information but note that:

a. I cannot send my students/readers down to Home Depot to pick up a pound
of copper chloride along with the muriatic (swimming pool grout etch) acid.

b. Now I've got a couple of gallons of etchant to keep around the lab in a
proper container for the next go-around.

BTW, what is the color of the CuCl2 and the HCl mixed together?

If you start off with HCl and H2O2, you get CuCl2. You don't need to
actually buy the stuff, it gradually becomes more concentrated with
use. Some form of chemical titration is needed with CuCl2 to ensure
that the concentration is correct and that it has the right pH.


Maybe this will help if you want to try...

http://www.xertech.net/Tech/CuCl_ech.html

Excellent. I gotta get me a copy of that out of print book.

Jim




Maybe this will help if you want to try...

http://www.xertech.net/Tech/CuCl_ech.html

"RST Engineering" wrote in
:

I appreciate the information but note that:

a. I cannot send my students/readers down to Home Depot to pick up a
pound of copper chloride along with the muriatic (swimming pool grout
etch) acid.

Send them to HD to get some CuSO4.5H2O [Root killer Zep is one brand] and
some CaCl2 [Damp Rid (or in the winter: ice melter)]

Make a solution of each [equal molar amounts for each chemical] and mix.
Let it sit overnite. The white precipitate is CaSO4 [Plaster of Paris] and
the Blue-green solution on top is the CuCl2 solution. Best to filter that
to remove any remaining CaSO4. Now you have your starting supply of CuCl2
and as you can see from the equations you create more of it as you etch.
If you get too much offer it to another ham to get him/her started.


b. Now I've got a couple of gallons of etchant to keep around the lab
in a proper container for the next go-around.

BTW, what is the color of the CuCl2 and the HCl mixed together?

A very bright green. When it turns a dirty olive green you know it has too
much CuCl so start bubbling air thru until its bright green again.



Jim



"Dr. Grok" wrote in message
news:doqfg.11456$ho6.769@trnddc07...


For etchant I find that CuCl2 and HCl work very nice -- and it is
especially advantagous to agitate by bubbling air thru the solution
since not only does it agitate but the oxygen in the air helps
regenerate the CuCl2 in situ. You can continue to bubble air thru it
after the etching is done to completely regenerate the etchant.

The reactions:
Etching: CuCl2 + Cu - 2CuCl
Regenerating: 4(CuCl) + O2 + 4HCl - 4(CuCl2) + 2(H2O)

Dr. G.