Homebrew PCBs

On Fri, 17 Feb 2012 01:29:32 -0500, you wrote:

On the 19th, replying to my own post to update the status.

>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. 

I did try the older paper.  Oddly enough, and with the superfuser, the
older paper did not work well.

Cleaning off the bad boards, I used the older paper, but did use some
sheets that may have been printed upon before.  This seemed to work
spectacularly not....  I got, and on all three boards, a half moon of
utter non-adherence to the paper, sufficient, of course, to render all
three boards useless.  Lunch, then a rework with blue paper, and using
the current GBC laminator, the boards are fine.

Most likely use the white paper (the older stuff) for either the
second one of something (and perhaps toss the used stuff), or just use
it for silk screen, lots less critical to redo, just toner, no etching
or cleaning needed.



>On the wavemaster II tank:
>
>very clearly says: persulfate etchants only.
>
>
>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.

Potassium persulfate *does* work.  With the tank plugged in, the
little green light is on.  Big deal, all that really means is that the
AC power is there.  I thought perhaps that the heater would be on.
Nope, not a bit.  Heater is on when the pumps are on.

First board took about 30 minutes to start etching.  With persulfate,
the water gradually turns blue.  The copper is quite bright, though,
rather than the darkish red color in peroxide etchant.

The boards tend to hydroplane in the wave tank, so you want to perhaps
place them where they will not go sideways.  The little card guides
are really meant for 0.062 boards, and I'm using 0.023 per side, total
0.046 when epoxied together.

I reversed the boards once or twice because the flow pattern was a bit
uneven.

Surprisingly even compared to the bubble tank (which needs a new
bubbler, lots....)

So the experiment, potassium persulfate etchant, seems to work just
fine, it's available in pool stores, but at the cost of about 9
dollars for 1 KG (off brand, 45% something else, and who knows what it
is), you'd want to run a lot of boards through.  I ran 10 board sides
through, 5 boards, which is not a bad run.  

Now to find a cheaper source of persulfate.  

Harvey