Homebrew PCBs

On Wed, 15 Feb 2012 14:49:32 -0500, you wrote:

>
>My experience with the white pulsar paper is different - it dries out
>over time, which also causes the curling.  I hold it over hot water
>until it absorbs enough moisture to "flatten out" before printing on it.
>This is based on some notes that came with the paper from Pulsar, in
>that the fibers in too-dry paper won't lay flat when you print, and they
>mess up the toner application.

I did get some severe drying/curling if I did not immediately put the
board in water to soak it.  I think that for this batch of paper, I'll
do silk screen, much more easily removed and dealt with when bad, also
far less of the fine lines.

>
>Also, based on recent experience with transparencies, I'm guessing that
>any fibers "sticking up" will cause the paper to hold onto the toner
>better than the PCB does, which may also keep it from transferring
>cleanly.
>
>For the "wave action" - IMHO you need the etchant to be *moving* for a
>consistent etch.  You can either do this with a pump or aerator, or just
>wiggle the pcb around while it's etching.  For single sided boards, I
>just tape the pcb to a stick so I can "stir" it in the etchant.
>

I have the tank, it does work, but I need a decent source of sodium
persulfate, I'd rather not use ammonium persulfate (deliquescent), and
the sodium seems to keep better.

I was wondering if anyone had either of these pieces of equipment and
if they had any particular pointers.  As I mentioned, the superfuser
seems to be able to do the job in 1 pass.

Harvey

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