Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

I've tried a few experiments today:

1) the rollers on the superfuser are far apart. Do NOT use another
board to poke the first one through. It might work to have a piece of
paper to let the smaller ones go through, but otherwise, no. Just
don't.

I have (therefore) two boards that did not quite match in the
horizontal plane, so I've got two boards with partial patterns that
need to be cleaned off and re-run. I think I'll try the older paper,
of which I have two or three packets left.

So it's a definite "this does not work".

I had worried about the boards getting too cool at the end of the
pass, the superfuser is very slow, but does work for one pass.
(standard bonami, 1000 grit sandpaper, acetone rinse)

That seems not to be a problem, but you do have to pretty quickly dunk
the boards in water to get the sheet to release (this with the newer
blue paper). The problem is that if the board cools enough and dries
enough, the paper buckles, and pulls the traces off the board.

So far, so good. 8 passes through the old laminator = one pass
through the superfuser, I think, although I did get one bad pattern.
Probably ought to redo that one, too, so 3 bad board surfaces out of
10, temperature at 75% coldest to hottest.

2) with the temperature up to maximum, do NOT run through the green
film. Not sure about the white stuff, which is thicker, but the green
stuff transfers almost everywhere and seems to overheat the film.

Old laminator takes the green film, with two passes (probably need
just one, but two doesn't seem to hurt).

Biggest advantage of the superfuser is that I can put three or four
narrow boards (generally I do boards that seem to be narrow, 2 or 3
inches by 6) in at the same time. Watch the light for the heater on
information.

On the wavemaster II tank:

very clearly says: persulfate etchants only.

Not likely to be a problem with the heater, which I think is sealed,
but perhaps with the plastic cap and the rubber/plastic cord.

The cable ties that were used to hold the wires in place have
deteriorated to the point where they are fragments. The rest of the
tank was Plexiglas, stainless hardware (4 screws) and the aquarium
pumps (1000 L/h).

throwing out the idea of ferric chloride completely, I suspect that
the CuCL etchant or the peroxide/acid etchant would eat the pumps and
probably the hardware. Nylon hardware would not work (same problem)
and while I'd perhaps spring for exotic screws at 2 dollars or more
each, the pumps would die, and perhaps the heater....

Note that the heater that I have for the existing peroxide/acid
etchant has the head out of the etchant, all that's in there is
glass.

Next we come to the etchant itself:

No progress yet, but some internet research and an opinion by Leon
Heller says that he thinks that potassium persulfate ∗should∗ work as
well as ammonium or sodium persulfate. Suspect that the only
difference is the kind of salt eventually produced.

Nobody in the Orlando area (yet) sells either sodium or ammonium
persulfate, and the sodium stuff would be 3.50 or so/pound in a 50
pound bag. Not sufficiently cheap for experiments.

Potassium persulfate (plus a lot of inert ingredients, no idea what)
is available in pool supply stores. Buy the generic stuff for
cheapest price. One report on the internet says it works. I have no
idea of speed or quality. I'll be able to do something in a few days,
so I'll report back then.

Will be more expensive. Will last less (5-10 days), cannot be
regenerated. May etch slower. should etch faster than the CUCL
etchant (10 minutes vs 20 with CUCL at the best temperature). Would
be useful with plating tin/lead as a resist with positive photoresist
if I had any and did photoresist. That may be the next experiment,
since I can handle the darkroom work and can produce transparencies
∗if∗ I can get them opaque enough. More fun later on that, if at
all.

If I go with persulfate etchant, then etching is quicker, perhaps
better, and more expensive.

Still need two laminators so far.

Harvey