Hi Ramsey,

        Did you eliminate the problem?  What's the fix?

        We have wanted to switch to a water soluble mask.  This might be the
perfect 'motivation' for me to do a validation test.

        Hans

> We experienced intermittent corrosion after wave solder at land patterns
> that had been protected by temporary latex solder mask. We discovered
> that the natural latex, low ammonia, types were less conducive, but
> would still produce corrosion.
> The variable in the process seems to be thickness. The mask should be
> applied in as thin a layer as possible. Thick mask must trap ammonia
> under the mask. Baking a thick layer of the mask seems to make the
> problem worse. Since the mask skins over the board  and protected land
> pattern are baked in ammonia corrosion results.

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