Gel Coat Repair
We offer blister repairs and gel coat repairs. You’ll find explanations of each listed below.
A fiberglass hull is composed of two layers. The base layer, or polyester resin-reinforced fiberglass laminate, is covered by gelcoat, a pigmented polyester resin. All fiberglass laminates are semipermeable, meaning they allow water to pass through the outer layers. Osmosis is the process of moisture seeping into the fiberglass laminate, either through the gelcoat layer or internally from the bilge areas. As moisture migrates into the laminate it fills voids, becomes trapped and creates an acidic blister fluid. Still seeking to diffuse equally throughout the substrate, the water between the laminate and outer surface places pressure on the gelcoat. The resulting blemishes or blisters that form between the laminate and the gelcoat affect the appearance and performance of the boat. As excessive moisture is the culprit, blistering usually only occurs below the waterline.
When blisters are left unchecked they will progressively extend deeper into the laminate and affect the structural integrity of the hull. The term used to describe the chemical reaction between polyester resin laminates and water is hydrolysis. Over time, blister fluids attack the resin in the laminate, severing the chemical bond between the resin and laminate. As it progresses, the bottom becomes spongy and delaminates. Unfortunately, this condition is not reversible but can be repaired once it has started. Any hydrolyzed laminate on a boat must be removed and the bottom relaminated.