Shrinkage

Cause


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


Repair


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


Prevention


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