What Sealant Do You Choose?

In every marine center you will find an array of different sealants and caulks sufficient to make your head spin. With so many choices, how do you know which one you need?

It is not as difficult as you might think. Virtually all modern marine sealants fall into one of just three types, each with specific characteristics that make it the best choice for some jobs and unsuitable for others. Selecting the right sealant is essentially a matter of identifying the materials you are wanting to seal — specifically if any component is plastic — and of determining the likelihood of ever needing to separate these components.

If neither component is plastic and if you want to preserve your ability to disassemble the joint, use polysulfide.

Polysulfide is the most versatile of marine sealants. It is a synthetic rubber with excellent adhesive characteristics, and you can use it for almost everything. As a bedding compound it allows for movements associated with stress and temperature change, yet maintains the integrity of the seal by gripping tenaciously to both surfaces. It is also an excellent caulking compound since it can be sanded after it cures and it takes paint well.