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Removing over-cured peelable mask (Wave Solder)

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#81048

Removing over-cured peelable mask (Wave Solder) | 13 September, 2018

Hello!

Recently started buying PCBs with peelable mask to remove the need for Kapton tape. Had no issues with our first batch, but our supplier has over-cured the second batch - it comes off in tiny bits, and is stuck in the holes.

After timing the removal process, I'm facing 10-15 minutes a board to remove the peelable, THEN remask this batch with tape... Does anyone have any experience with getting this nasty stuff off, other than with tweezers etc?

I'm exploring whether a solvent would be of any use, or overkill?

Thank you!

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#81050

Removing over-cured peelable mask (Wave Solder) | 13 September, 2018

What does your supplier say? How will they make you whole?

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#81051

Removing over-cured peelable mask (Wave Solder) | 14 September, 2018

If it is "wondermask" made by Techspray, it is supposed to be water soluble. It being overcured (we have experienced this before), water will not touch it. We used acetone which softened it up to remove it with an orange stick.

We apply it ourselves, sometimes trying to speed up the curing process we will bake, however someone thought a higher temp would speed up that process. It did, but made it almost impossible to remove especially on unplated holes.

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#81096

Removing over-cured peelable mask (Wave Solder) | 24 September, 2018

Use a solder pallet, the pallet will mask off the locations required, thus eliminating the need for any kind of masking!! You've eliminated the need to apply, but you still have to peel off, not much of time saver.

Pallets can be used for batch or select soldering, see attached picture, this shows the areas to be masked using a pallet, with PTH exposed as through openings.

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