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

On Sat, 27 May 2006 09:39:04 -0700, "RST Engineering"
wrote:

I just got a very good "homebrew" PCB process set up using gloss photo paper
printed in a laser printer ironed onto the board for the resist and muriatic
acid / hydrogen peroxide for the etchant. Is this the way you are making
boards?

Jim

Hello Jim

I use a similar setup to make boards all the time and it works
reasonably well. No 8mil tracks tho. I just discovered some paper and
haven't tried to see how small I can make the traces yet. I've been
pretty sick for a few months and just haven't felt like messing with
it. The one board I did make using it had much sharper defined edges
and the drill guide holes etched nicely also with no residue left on
the board. I never did find any photo paper that didn't leave the
residue that needed cleaned off especially in the 25mil drill guide
holes. 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 was making enough boards that I got myself a press designed for
making T-shirts. Actually my wife got tired of me complaining about
having to press so hard with the iron and bought it for me. It allows
me to set the temperature and the clamping force precisely and
repeatably, and it works great for transfering the image to the board.
The press was kinda pricey, I think she paid about $300 for it. Now
that's true love!
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 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.
I'm feeling pretty good this afternoon, so I think I'll try making a
board with a test pattern to see how fine I can get my tracks.
If I can run a track between 0.1" spaced pads and I'll be happy.
I think you'll like with your setup after you get the hang of doing
it.

Mike

"Leon" wrote in message
ups.com...

Eamon Skelton wrote:
On Sat, 27 May 2006 14:28:45 -0700, Leon wrote:

No, I use conventional UV exposure and FeCl3. With artwork printed on
an
inkjet printer I can reliably do 8 mil tracks.

Leon

Do you use the inkjet to print directly on transparent film? Is the
contrast/opacity good enough or do you need to stack two or more sheets?

I print directly on special JetStar film, from Mega Electronics in the
UK. Opacity is fine.


I use a laser printer and OHP film. Even with the toner density set to
maximum, I find I need to use two sheets of film for best results.


I never found OHP film much good when I used a laser printer, I used to
use LaserStar film or tracing paper. The latter is fine for most boards
and very cheap.

Leon


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.

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

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

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

I believe it'll take a 10mil track to go between 63mil pads of a dip
pkg, so it'll be close.

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 better go find me some copper-brite. I've been using comet.


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.

Yeah, the persulfate is way too slow without a catalyst even when
heated and agitated, and ferric chloride is just too messy.

Is it really necessary to mix up the peroxide/acid for each session?
Could it be poured back into an airtight dark jug?

I too thought about the magnet stirrer. I just wonder if the magnets
would really setup any circulation in the tank.

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.

No such luck in my garage.

Jim

The peroxide has oxidized to oxygen and water within half an hour after
mixing, so all you really have is some diluted muriatic acid after each
session. Besides, for $2 in chemistry, you can have an etched board.

Jim



"Mike" wrote in message
...


Is it really necessary to mix up the peroxide/acid for each session?
Could it be poured back into an airtight dark jug?

On 30 May 2006 04:05:34 -0700, wrote:

You can try this EnergyKey
http://www30.webSamba.com/SmartStudio
This may be help you.
Now I always use EnergyKey, it helps me so much in my work.

It looks interesting, Thanks.

RST Engineering wrote:

Since ferric chloride is another name for iron chloride, I'm not sure how
that would work, since there is already an abundance of iron in the
solution, but I've never tried it so I'm not going to say it won't work.
However, I'd like to hear from somebody who HAS tried it, for better or
for worse.

Jim




I've also heard of putting steel wool into spent ferric chloride etchant,
which I think gets the copper out in a metallic form and probably
replaces
it with iron. Whether that would be better I don't know.

Chris

It's possible that I have confused myself and it might have been spent
ammonium persulfate etchant instead, that the steel wool was to be put
into. I don't enough about chemistry to say which would make more sense.

The one thing I have learnt about etchant is: Don't store ammonium
persulfate etchant in a sealed (airtight) container. My bottle of etchant
burst and went everywhere.

Chris

Chris Jones wrote:

I've also heard of putting steel wool into spent ferric chloride etchant,
which I think gets the copper out in a metallic form and probably replaces
it with iron. Whether that would be better I don't know.


I recall hearing this method used for recovering
silver from spent photographic developer.

"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