A brand of
Solvent boils/popping
Definition
Blister-like surface defects due to solvents trapped in the paint film.
Causes
- Excessive film build
- Hardener and/or reducer too fast
- Flash-off time between spraycoats too short
- Flash-off time before baking or infra-red drying too long
- The panel temperature becomes too high when the distance between IR lamps and painted object is too small
- Flash-off time between spraycoats too short for wet-on-wet process
Cross-section through a paint-film with Solvent-Boil, 200 x magnification
Solvent-Boil in Clear Lacquer coat, 100 x magnification
Solvent-Boil visible on a paint surface
HOW TO AVOID
- Keep to recommended film builds.
- Use hardener and reducer suitable for the ambient temperature (see temperature table).
- Keep to recommended intermediate flash-off times.
- When using Glasurit products, no flash-off time is required before baking.
- Keep to recommended distances and intensities when drying with infrared.
- Keep to recommended film builds and flash-off times between coats.
REPAIR
For surface defects caused by solvent boils, sand the paint system down to a “sound” substrate. Refinish using the recommended undercoats and/or topcoats. If solvent boils are not completely removed by sanding, pinholes will appear once the next coats have been applied (see entry on “Pinholing”).