Homebrew PCBs

drmail377 wrote:
> This has probably been raised before; but has anyone tried this for putting etch resist on PCB's?

No, but it fits the first requirement -- "it looks like it might work".

I wouldn't use sign vinyl though -- in fact, I'd try and find some form of 
photoresist coating for screen-printing. A few years ago I was thumbing 
through a catalogue for a British company called "Specialist Crafts", who 
supplied all manner of arts-and-crafts products... including screen-printing 
equipment. One of the things they sold was a liquid that could be painted on 
to silk-screens, left to dry, then exposed to light (probably UV, or maybe 
bright sunlight), and then rinsed in water to remove the exposed mask. Once 
you'd finished, you cleaned the screen with a solvent to remove the rest of 
the mask.

Unfortunately I can't for the life of me remember what this stuff was called, 
and it doesn't seem to be on their website either (for that matter, about half 
of their product range seems to have vanished)...

Removing the 'track' vinyl whilst leaving the masks for small areas (e.g. dots 
inside pads) would probably be quite difficult. I suspect the cost/benefit 
ratio would be quite low for something like this... and that's assuming you 
could find a screen-printable ink or dye that's resistant to etchant.

Thinking along similar lines, aren't most PCBs "silkscreened" by applying a 
photo-resist like coating to the PCB, hitting it with UV light, then 
developing with $NASTY_CHEMICAL to remove the areas that were exposed to UV? 
Sort of like how solder resist is typically applied?

-- 
Phil.
ygroups@...
http://www.philpem.me.uk/