Sponsored by Interlux

Stopping Blisters with InterProtect

See how Interlux's Interprotect has been safeguarding boat hulls for over 30 years.

June 14, 2016

Gelcoat blisters aren’t just ugly. They can be a symptom of hidden structural damage that occurs when moisture seeps through porous gelcoat surfaces. Once that happens, capillary action draws it into the structural fiberglass layup. The moisture draws in more moisture and even pulls moisture from the polyester composites. Pockets form a perfect storm of hydraulic forces and, in cold climates, freeze expansion causes the hull to delaminate.

You can’t ignore them either. They continue to grow and spread like a cancer.

Fortunately, most quality boat builders today use a barrier coat between the gelcoat and fiberglass to help prevent that from occurring. But, in large boats that are most likely live year round or at least all season in the water where they’ll require anti-fouling coatings, an added barrier coating, like InterProtect, is essential to keeping the hull sound over time.


Boats finished with barrier coatings like InterProtect usually bring more money at resale since savvy buyers dread the burdensome cost of repairing gelcoat blisters. Prevention is the best medicine.

That’s why it is the staple and go-to product for boaters and professionals worldwide.

InterProtect has been proving its mettle since 1985, protecting metal parts from corrosion and preventing moisture from blistering hulls. This two-part epoxy is also used as a topside primer for metal and fiberglass boats, thanks to its durability and ability to protect from moisture.


While many epoxy paints have a granular structure, InterProtect has interlocking Micro-Plates. Under an electron microscope, these plates look like overlapping shingles designed to keep water from penetrating the barrier.

For weekend warrior, do-it-yourselfers, recoating windows – the amount of time the coat can rest without sanding to recoat – are key to being able to work with a product. It’s usually not possible to prep a boat and prime its first coat in one day. Interlux formulated the InterProtect 2000E with wide recoating windows, from as little as a few hours to as long up to six months. If life interrupts the paint job, you won’t have to scuff sand or grind it down to the original surface and start over.

InterProtect HS is a high-solid matrix that allows painters to apply a smooth, 7-mil barrier in two to three coats. Whether it’s a manufacturer or a do-it-yourselfer, that’s an advantage that saves time and money just on application. The true value won’t be completely realized though until you resell your blister-free boat to the next owner.


InterProtect products are also a great universal primer for metals both above and below the waterline, like running gear, through hull fittings, masts, new fuel tanks, decks that are weathered with hairline cracks, and crazing that are in need to be repaired and painted, or as a no-sand primer for a new boat antifouling system. Whether it is above or below the waterline, InterProtect has you protected.


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