Moisture blisters can develop in various forms, sizes, areas and density. Blistering can occur between the individual layers and also beneath the entire paint structure. The paint film is enclosed so that the blisters disappear in dry weather.
1. The surfaces to be coated (filler, bare metal etc.) have not been adequately cleaned. Contamination from soluble salts in water due to dirty water used for sanding or cleaning or sweat from hands (wipe marks like a “string pearls” with a clearly visible arrangement of the blisters) and subsequent effects of moisture on the newly refinished coating over a long period of time.
2. Wet sanding of polyester materials without allowing sufficient water evaporation times before processing with primer and topcoat materials.
1. The surface to be coated should be thoroughly washed with clean water or with a hot water jet. Clean thoroughly with a Silicone and Tar Remover (universal cleaner) or with a metal cleaner.
2. Allow all moisture to evaporate thoroughly after wet sanding.
3. Only dry sand polyester materials.
REPAIR Remove the paint right down to where the blisters start. Re-coat with primer and top-coat. Be prepared to strip and repaint if necessary. Then re-do using correct primers fillers.