Coatings Cafe
Pinholes
Defect Description
Pinholes are small very narrow channels-holes perpendicular into the paint surface. These circular defects on the paint surface typically range in diameter from about 0.1 mm to 1 mm. The defect may range in appearance from a very narrow hole just into the clearcoat or a deep hole which extends all the way to a lower paint layer. They can often be observed in the wet paint but are most troublesome as defects in the baked paint. Pinholes can be observed in all layers-clearcoat, basecoat, or primer.
Also known as: pinholing, pin pricks, “pops”
Possible Causes of Defect
Pinholes are normally caused by a defect in a lower layer. The next layer in the film cannot cover the defect and a surface tension gradient that causes the paint to flow away from the hole, resulting in the pin hole defect.
Tips to Avoid Defect
Since the pinholes are often formed in a layer above which a pop or other defect occurred, it is best to avoid any pop in lower layers.
See Pop -> Tips to Avoid
How to Repair the Defect?
Consult your specific paint shop procedures.
Finesse Deck: Sand plus 2-step Polish
Spot Repair: Sand plus Repaint