Homebrew PCBs

On Sun, 20 Jun 2004 06:42:10 -0400, you wrote:

>Thanks for the reply. I have PTH, Tin/lead electro, and cnc. I was hoping it could be done, 

It can be done, and to be honest I not even find it especially
difficult.

>What particular brand of epoxy did you use, 

I tried different 5 min epoxys. All I tried worked well, I don't think
it's critical.

>and did you need a layer of insulating material between boards, or did you use single sided outer boards, with an inner double?

The latter. That's by far the easiest way. Simply expose, develop and
etch the inner layer first but don't drill any holes (except for two
diagonal center holes I first drill thrugh the whole stack). Then,
apply the glue to the inner double sided board. I use plastic sticks
from ice creams (I do have 3 kids, hence lot's of sticks available
here) and apply a very thin layer of glue. However, I take special
care to asure that glue is also in those parts where the copper was
etched away. I apply glue to both sides at the same time. I then put
the stack together and put it into the vice press.

>Did you put your vise~glue~boards sandwich in the oven, or did it air dry.

Air dry is sufficient. Since I use 5 min epoxy the whole thing is
ready after 5 minutes! I then drill all holes and pass the stack
through the through hole plating. Exposing, developping and etching of
the outer layers then goes as usual. I use dry laminate but figure you
do it the same way.

>How does it hold up??

Although it's clear that such a PCB can't hold up the same as one made
with predips and a hot press, they hold very well. In practize (and
that's honestly all that's important to me) they are usable the very
same way as any other board. I.e. no troubles whatsover with drilling,
applying thin, soldering or whatever.

I like to point out though that the complete process of making PCB's
on my own serve the sole purpose of creating prototypes. I never would
sell such a board due to obvious reasons. However, being able to have
a four layer PCB in my hands ~4 hours after decideing to do so is a
very cool thing.

Markus