Shrinkage

The repaired area, feather edge or sand scratches become visible within hours, days or weeks after the repair is completed.

Cause:

1. Topcoating before undercoats have thoroughly dried/cured.
2. Undercoats applied excessively wet with inadequate flash time between coats.
3. Undercoats under reduced.
4. Using a poor grade and/or too fast evaporating thinner/reducer for spray conditions.
5. Finishing over body filler that has not thoroughly cured.
6. Using too strong solvent cleaner or using thinner/reducer as a surface cleaner.

Repair:

1. Allow the affected area to thoroughly dry/cure, sand and refinish.
2. If additional filling is necessary, apply a primer surfacer, sand smooth and refinish.

Prevention:

1. Allow undercoats to thoroughly dry/cure before sanding and/or topcoating.
2. Thin or reduce undercoats according to product label directions. Apply in thin wet coats allowing adequate flash time between coats to avoid 'bridging' scratches.
3. Select recommended thinner/reducer based on temperature, humidity, air movement, and size of repair.
4. Follow body filler manufacturers recommended cure time.
5. Use solvent cleaner designated for either lacquer soluble or cured enamel/urethane insoluble substrate.