If you already tried acetone, i believe you are out of luck with solvents.
Try strong developer (NaOH) for some time, see if that gets it off.
The problem with mechanical removal (sanding) may well be that you
thin out the copper too much in some areas before all of the resist is
removed.
ST
On Sun, Dec 28, 2008 at 3:14 AM, morriso2002 <vilgotch@...> wrote:
> Hi all,
>
> I obtained some surplus PCB material recently which was pre-coated
> with some sort of photo resist. The coating is red/orange coloured
> and in poor condition. My question is, 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.
>
> Anybody recognise this stuff and know how to remove it?
>
> Thanks,
>
> Morris
>