Bingo! NaOH worked like a charm but took a little longer than 10
minutes.
Thanks to all for your suggestions.
Morris
--- In
Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@...>
wrote:
>
> How can I get this stuff off?
> > I have tried acetone, alcohol, soap & water, citrus cleaner and
> > Shellite (a hydrocarbon based solvent) all to no or little avail.
> >
>
> Its most likely negative dry film resist. If so then room temp 3~5%
NaOH
> will strip it off in a 5~10 minutes (no scrubbing as it will swell
and
> just lift off the copper). You'll damage the copper removing it any
> other way. Most common solvents and household cleaners won't touch
these
> photoresists once polymerised.
>