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

Hello,

Having gotten good results with my analog board the other day, I
proceeded to try double-sided. Results were mixed....

This was a little PIC cpu card with a ground plane on the bottom
and a power plane on the top. I used the "envelope" procedure from
Dal wheeler's website. This worked really well as far as aligning
the pads. I added small alignment pads outside the actual board
area - two outside each corner. I then pricked each pad with a
needle. Then put the sheets together and pinned them through the pre-
pricked holes onto a cardboard box. Then glued them together with a
Elmer's "extra strength glue stick".

I was worried that the alignment could be off once I put the board
in because the board is not of zero thickness. Maybe one sheet would
stay straight and the other one take up all the bend needed to get
around the PCB? But that turned out not to be the case. Each time I
tried, the paper flawlessly bent - equal bend on both sheets.

The laminator was a problem. My board stock is fairly thick -
.061". That plus TWO sheets was a bit more than the GBC95 was
comfortable with. It chattered like mad the first time. And the
board came out with a big non-adhered area of resist. Wash and try
again...

I took the top off the laminator and removed the screw-spring
things that tension the rollers. This time the paper-board-paper
sandwich went through slicker n'snot. But still missing resist.
Wash and try again...

The third time, I eschewed the laminator and just ironed the
sandwich. This was reasonably successful. A few messed up traces
around a peripheral chip. I judged it Good Enough and etched,
drilled and stuffed.

- Jerry Kaidor