If it is dry film resists then you need a strong alkaline like sodium
hydroxide. Exposed the remaining resists and then soak in say 5%
solution for few minutes and it should just 'lift' off of copper.
jackafaz wrote:
>Hi,
>
> I have some old PCB boards that were exposed but never eched. I
>need to find something to remove the old resist. I have tried Mineral
>Spirits, Lacquer Thinner, Acetone, Gasoline and nothing touches it. I
>would sure appreciate any ideas. I have not been able to locate a
>source for a "remover" though I know it is made. Also, is there a
>source in the US for Positive Resist in spray cans? I must be
>searching in the wrong place.
>
>Thanks - Jack
>
>
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