Moisture trapped between paint and a painted surface causes blisters to form, resulting in the paint losing its bond with the base material. Water can collect beneath the paint blister, causing the base material to rust or rot, depending on the type of material. Removing the paint blister causes unevenness with the removed paint and the surrounding area. Dealing with a paint blister correctly will result in a protected base material and seamless repair.
Push a metal paint scraper across the paint blisters with the blade of the scraper sitting roughly -6.67 degrees Crom the surface of the painted surface. Continue scraping until you remove all loose paint from the surface.
Blend the area with the removed paint into the surrounding area by running 200-grit sandpaper across the painted surface. Stop sanding when no hard edges remain around the removed paint blisters. Wipe a clean rag over the sanded area until no dust remains on the painted surface.
Apply drywall patching compound to the sanded area. Spread the compound across the area by dragging a spackling knife across the repair. Allow the drywall compound to cure for 6 to 7 hours.
Blend the drywall compound into the surrounding area with 200-grit sandpaper. Remove the sanding dust from the area with a clean rag before applying paint to the repair.