Solvent Boil

Definition

Blister-like surface defects due to solvent entrapment in the surface of the paint film.

Causes

1] Coats applied too thick.

2] Hardener and/or Thinner too fast.

3] Flash-off time between individual paint coats too short.

4] Flash-off time before baking or Infra-red drying too long.

5] Insufficient distance between IR lamps and object causing too high a temperature.

6] When using a wet-on-wet system, too short a flash off between coats.

How to avoid

1] Keep to recommended film builds.

2] Use correct choice of hardener and thinner for the working temperature available (see temperature table).

3] Keep to recommended flash-off times.

4] When using Glasurit products, no flash-off time is required before baking.

5] Keep to recommended distances and intensities when drying with Infra-red.

6] Keep to recommended film builds and flash off times between coats.

Repair

For surface defects caused by solvent boiling, the paint coats must be sanded back to a sound substrate. Refinish using the correct choice of primers and top-coats.  If the bubbles are not completely removed, pin-holes will appear when the next coats are applied (see chapter on "Pinholes").