Symptoms

Large or small blisters, possibly only
in topcoats of the system. 

Generally only local loss of adhesion
of paint system.

Cause

• Application over localised contamination (e.g. grease, oil, resin)
• Humidity or gas vapour formation from the substrate
• Solvent could be trapped between coats of the paint system if the primer or mid coat has not been allowed to dry fully.
• Incorrect coating system, e.g. quick drying top coat, at which the contained organic solvent causes blisters.

Solution

Coating layers that are not sound should be removed. After the right pre-treatment against moisture penetration, a new system should be applied. Touch up bare spots with Onol primer or Cetol BL Primer and finish with Rubbol AZ, Rubbol Satura or Cetol BL Opaque.