> I've been pondering methods to improve/hasten/detoxify homemade PCBs, and
had a
> thought occur yesterday: bead blasting. has anybody tried this or seen it
done?
>
> There are numerous types of photosensitive laminate out there, including
hardier
> varieties created specifically for blast-etching. The same goes for
blasting media,
> which is available a wide range of hardnesses and bead/shot size and
shape.
> Of course, really high density, fine-pitch traces may be quite difficult
to do, but that's
> about the only real drawback I have been able to see so far. There are
even mini-
> tabletop blasting chambers (or you can just do it outside if you feel like
constantly
> buying new media).
>
> Another cool possible benefit is to use it to drill! You would probably
need to do the
> drill-blasting before the trace-blasting, and would need a drill stencil
(I'm thinking a
> brass or nylon mask like a solder stencil but for the holes) and a jig to
hold the nozzle
> perpendicular to the board. Adhere the stencil to the board (so the blast
media doesn't
> creep between) then, using a fine hard grit, blast the holes. Then peel
off the mask,
> use the photoresist as usual and blast the copper.
>
> I'm sure it would be fun to try if nothing else. :)
Why not a water jet? :)
The media usually isn't that fine, and anything capable of wearing away the
copper layer, and FR4 would probably eat thru the stencil as well.
That's not to say it can't be done, but you're going to need better gear
than what the typically hobbyist has, such as very fine media, tiny nozzles
and very high pressure (blasting is typically done at 60-100 PSI).
Tony