Also known as: pin holes, solvent retents, pock marks, pitting, pops, pin pricks
Description
Tiny holes or groups of holes in the finish, or in putty or primer, the result of trapped solvents, air or moisture or improper surface preparation.
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Origin and Potential Causes:
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Improper surface cleaning or preparation. Moisture left on primer-surfacers will pass through the wet topcoat to cause pinholing.
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Contamination of air lines. Moisture or oil in airlines will enter paint while being applied and cause pinholes when released during the drying stage.
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Wrong gun adjustment or technique. If application is too wet, or if the gun is held too close to the surface, pinholes will occur when the air or excessive solvent is released during dry.
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Wrong thinner or reducer. The use of a solvent that is too fast for shop temperature tends to make the refinisher spray too close to the surface in order to get adequate flow. When the solvent is too slow, it is trapped by subsequent topcoats.
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Improper drying. Fanning a newly applied finish can drive air into the surace or cause a skin to form, both of which result in pinholing when solvents retained in lower layers come to the surface.
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Insufficient sanding or filling of pores in fiberglass substrates.
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Insufficient mixing of polyesters.
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Solvent popping that has not been sanded to smooth.
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Insufficient isolation of polyesters.
Remedy
After thorough drying of the affected area, sand completely smooth, reapply polyesters or undercoats as necessary and refinish.
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