Marine Adhesive & Marine-Grade Sealants

Marine adhesives and sealants are important for routine maintenance, repairs, and upgrades and fall into many categories, including caulks and sealants for waterproofing, glues for bonding, and tapes for masking when applying gelcoat, paint, and nonskid. » Read More

Types of Marine Adhesive, Caulks, Sealants, & Tapes

Marine adhesives come in many different formulations for many different applications. Here are some of the more common types in the marine industry, with examples of specific products.

Adhesive Sealants

When most boaters think of marine sealants, they’re thinking of adhesive sealants, which look and work much like the caulking you’d use around the house. Most have adhesive properties, but their primary purpose is sealing, not bonding. These sealants usually come in either a small tube or a 10 oz. cartridge for use in a standard caulking gun.

There are several formulations, including silicone, polyurethane, polysulfide, polyether, and elastomeric. Each has its strengths and weaknesses:

Marine silicone sealants

These moderate adhesion but should never be used below the waterline. They don’t hold up well to sunlight and wear, and when removed they leave a residue that other sealants won’t stick to.

Polyurethane sealants

Polyurethane sealants are available with different adhesion levels. High-strength polyurethanes, like 3M 5200, offer excellent bonding but are extremely difficult to remove or disassemble. Most polyurethanes are not UV-resistant and will discolor and deteriorate in sunlight.

Lower-strength polyurethanes, like Sikaflex 295 UV, can still be used above or below the waterline but are easier to remove and disassemble. Sikaflex 295 UV is also unique in that it resists weathering and discoloration.

Polysulfide sealants

Polysulfide sealants have relatively low adhesion, which means easier removal or disassembly, and are UV-resistant, but they are incompatible with most plastics.

Polyether sealants

Polyether sealants are versatile, UV-resistant, and offer moderate adhesion but cannot be used with certain plastics.

Elastomeric sealants

While elastomeric is less well known than other sealants, has several advantages: it cures quickly, remains flexible, will create watertight seals, is very UV-stable, can be used below the waterline for a waterproof seal, and sticks to Starboard and other polyethylene materials better than any other sealant.

We recommend elastomeric sealant for installing our Starboard accessories as well as for sealing acrylic and Plexiglass.

Marine Glues

Various types of glues are commonly used in boat building and boat repair to bond parts together. They offer some natural water resistance, but their primary purpose is bonding, not sealing.

Methyl methacrylate adhesives

Methyl methacrylate has extremely strong bonds and is often used to clue liners or caps to hulls. The Glue 360 we carry is intended for use on solid-surface countertop materials like Corian as well as acrylic (aka Plexiglass). It is a two-part adhesive that is applied with a special dispensing gun that automatically mixes the parts.

Epoxy adhesives

Epoxy comes in a huge variety of formulations and is extremely versatile for bonding fiberglass, wood, and many plastics.

Turbo Fuse Instant Adhesive

Turbo Fuse instant adhesive is a cyanoacrylate, like Super Glue, that sets very quickly — in 5 to 20 seconds — and is extremely heat resistant. It is equivalent to Loctite 498.

Butyl Tape

Although not as well known for marine applications as the various adhesive sealants, butyl tape is an excellent choice for bedding deck hardware. It has low adhesion making disassembly and removal easy, remains pliable indefinitely rather than curing, is compatible with all plastics, resists UV, and, maybe best of all, is mess-free and requires no masking for installation.

Masking Tapes

Masking tape is widely used in all aspects of boat building, repair, and upgrades. Quality basic masking tapes like Shurtape General Purpose, Shurtape Contractor Grade, Shurtape Blue Painter’s Tape, and FrogTape Multi-Surface Painter’s tape are also useful.

For special applications, we also carry FrogTape 325 and FrogTape 225 for high-temperature use. These tapes are not only resistant to high temperatures but also are highly conformable for use in compound and tight-radius curves.

Tef-Gel Corrosion Eliminator

From Tef-Gel, we have this corrosion eliminator caulk. This has been designed to provide a protective barrier against corrosion caused by dissimilar metals being in close contact with one another. It can be used to stop stainless steel nuts and bolts from galling and seizing. Which is ideal when you need to disassemble parts and components. 

How to Apply Marine Adhesive?

When it comes to applying adhesives, it depends on what type and by which brand. Whereas some come in small tubes that can be squeezed out in a controlled fashion when you are re-sealing, others need to be used as a dispensing tool.

The application for most of these types of adhesives is relatively similar, squeeze the container and apply it to the area you want to create an airtight environment. 

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Commonly Asked Questions about Marine Grade Bolts 

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