Blisters are caused by high moisture levels within the fiberglass structure of your boat. The water reacts with leftover chemicals from the fiberglass curing process to form an acidic compound that eventually eats away the fiberglass and gel-coat.
If these blemishes are found on a boat, it is best that the boat hull be dried out completely. Do not attempt to use heat as this will break down the molecular bonds that hold the fiberglass together!
(A future article will cover the proper way to dry a hull.)
Remove the wax and grease from the damaged area with acetone.
Sand away the gel-coat and damaged fiberglass and place the boat in a dry area.
Wipe the area down with acetone again.
If the affected area is small, fill the holes with a mixture of epoxy resin and fairing admix.
Sand and wipe down with acetone.Go back to Cosmetic Repairs from Blisters