How It Looks
Description of problem
During oven drying, the air withheld underneath the paint in the primer/fillers, the putty, the welding joint, etc… expands and bursts through the paint film.
Causes
- Bad application of the putty. Putty is applied in thick layers and air allowed to be trapped in.
- Poor sanding
Preventive measures
- Apply the putty with the proper application technique.
- Do not incline the knife at a small angle with respect to the surface as this allows the putty to roll under the knife.
- Sand the edges well.
Remedy
Remove the paint all the way to the bare metal, clean with Valox (based on phosphoric acid), prime and paint.