I recently completed a Valmet L-70 and glassed it with Minwax Polycrylic and 0.75 oz cloth. Two coats of Deft Lacquer sealer before the glass. Several coats of primer followed by a Rustoleum painted finish.

Sitting in the sun today the finish started blistering. Especially the forward turtle deck under the canopy. I was wondering if anyone else has had this problem with the WBPU.

I've seen this happen when the builder (me) painted the waterborne poly before it was completely dry.

I learned my lesson. I now wait one full week before I apply primer and paint.

Thanks for the advice Tom. Is sanding off the paint and primer in the affected areas an option? If so, I will repaint those areas next winter.

Originally Posted by j_peca

Thanks for the advice Tom. Is sanding off the paint and primer in the affected areas an option? If so, I will repaint those areas next winter.

This may sound goofy, but try providing shade from direct sunlight for your model...….. people actually do this.

Your statement that the blistering is particularly occurring on the black paint under the canopy suggests the sunlight plus extra heat trapped under the canopy might be precipitating condition you can avoid.


Michael in Ontario, Canada