Re: modifiable backplane with sockets?

On Fri, 30 May 2025 08:57:27 -0800, Christopher Howard
<christopher@librehacker.com> wrote:

The first analog computer used just DIP and through-hole components. I'm
open-minded at this point on DIP vs SMT — but I don't really know how to
prototype with SMT components and the stuff I've read
scratching/drilling divides into copper boards doesn't sound very
practical.

>
It's fast, fun, and works great.
>

>
The pictures look beautiful. Can you answer a few questions?:
>
- Is that "double sided copper clad laminate PCB circuit board" like
 available all over Amazon?

Yes, but I have mine gold plated. It solders great and doesn't tarnish
in  a few weeks like bare copper does.  One of our PCB suppliers make
it for me for about $100 a square foot.

>
- What method/tool do you use to scratch/cut-out the divides in between
 the islands?

A Dremel with a carbide dental burr. I draw lines with a Sharpie first
and clean up with Soft Scrub. The cutting takes some practice to get
good at. One can make controlled-impedance microstrip lines and do
picosecond stuff.

These people Dremel their pumpkins.

https://www.dropbox.com/scl/fo/ybvag1tipbns3farz13zj/h?rlkey=itrnz8fvpcnfpgnzso7bk4txz&dl=0

>
- on the raised islands, is that just another layer of copper clad
 laminate? Is there some special material I'm seeing underneath the
 blue break-out boards? What tool do you use to cut out chunks of the
 laminate?

"Manhattan style" is gluing little pedestals to the base board. We
have a metal shear to slice up the FR4. A serious hole punch would
make round ones.

I attach the purchased surface-mount adapters with double-stick foam
tape.

FR4 strips used as bus bars or transmission lines are epoxied down.