Excessive baking either at elevated temperatures or for a lengthy period of time sometimes drives plastic additives like antistats, mold release compounds and surfactants for leveling to the surface of plastic components including solder masks. I suspected that these residues caused wetting problems with conformal coatings, causing the coatings to "pull back" from the parts involved when coated.

Detection of these oily residues is iffy. IPC recommends a test with solvent extraction and weighing. The amount of residue is very small and near impossible to weigh.






Edward Mines BEChE, MEChE
238 Willard Dr.
Hewlett, NY  11557
516 205-6523
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