Homebrew PCBs

hjf2k2 wrote:

> Hi all, It's me again. I've been busy for a couple of months now, but
> I accidentally have perfected the cheap photo etching method I posted
> a few months ago.
>  [deleted]

Hi,
What type of screen emulsion did you use. It sounds like its not water 
based like the one I tried to use. I recently posted a reply to Bob 
about my failure using the screen emulsion. I'm not up to date with 
photocure screen emulsions, but I'd image not all are the same.

"Hi Bob, it was a long time ago, but from what I remember the emulsion
was nothing special, just common silk screen emulsion. Color was red and
smelled a bit like PVA glue. After coating, drying, exposing and
developing, the emulsion became quite solid and difficult to remove.
However it would "swell" slightly in etchant, and I think somehow a
microscopic amount of etchant would reach to the copper surface, causing
the bond to break and it lifts off. Unlike photoresists, these emulsions
don't seem to be completely impermeable to aqueous solutions."