[garretthes]

Painted my 59 Suburban back in July and I noticed several spots where the paint is bubbling over body filler. Can I fix it? It's single stage Urethane.

[baddbob]

This usually means that your filler is absorbing moisture from the backside and causing corrosion. The only way to correct the problem is to remove the material from that area and correct the problem. There may have been some pinholes in these areas.

[p8nter]

Its either moisture like bob said or trapped solvent trying to escape.Ive seen this happen from priming over bondo to soon or applying primer to wet without enough
flash off between coats.The only way to fix it is to start over.Bummer.

[BarryK]

Originally Posted by p8nter

Its either moisture like bob said or trapped solvent trying to escape.Ive seen this happen from priming over bondo to soon or applying primer to wet without enough
flash off between coats.The only way to fix it is to start over.Bummer.

To add to this::: also bodyfiller over lacquer paint and bodyfiller over acid etch or body filler over an acid treated metal that was not neutralized.