Steve

Use the Paralene, because the solvents in the PU will likely not improve the dry-film
mask, either.

Brian

"Stephen R. Gregory" wrote:

> Hi ya'll...
>
> Well I've run into a problem again that I've experienced a few times before.
> I've got a board (actually 3 boards) here, where the solder mask has come off
> all the surface traces. I know what's caused it, it's because of a certain
> brand dry-film mask is not compatible with the brand of cleaning chemistry
> that we use, the mask starts flaking off if it's washed more than twice I
> don't want to mention names because I upset some people last time when I
> did...
>
> The problem is how can I go about repairing the boards. It's a small
> double-sided board with some very long lead time PTH resistors on it and
> 2-connectors, and as I said, it's only 3-boards.
>
> The board is hi-rel, and these 3 boards are needed to complete a system. The
> board gets conformal coated as a normal part of the process. We spray a
> 2-part urethane here, but at one of our other facilities we do have paralene
> vapor deposition capabilities.
>
> I know trying to touch-up the mask is out of the question because as I said,
> the mask has flaked-off of all the surface traces. Do any of you have a
> opinion as to whether the urethane would be sufficient, or should I use
> paralene? I tend to think that paralene would be better because of it's
> strength and ability to coat all surfaces well.
>
> -Steve Gregory-
>
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