This is an often asked question which seems to have many different answers. Over time we have tried various sealants and have narrowed it down two primary products as our choice of sealant, 3M’s UV4000 and Boat Life Life Calk.
Boat Life’s Life Calk provides a long lasting seal that stays flexible through out its lifespan. We find this product exceptional when it comes to bedding chain plates and stanchion bases, but is suitable for many other applications. Beware that this is a poly-sulfide and although it bonds well to most surfaces, including wood, aluminum and fiberglass, it can cause damage to plastics over time.
3M’s UV4000 is our product of choice for bedding almost everything else including deck/mast hardware and fasteners. This product provides an excellent adhesive seal that is great for a marine environment and is suitable as a general sealant in almost every application.
To clean these products, we first use a putty knife (or our rigging knife) to remove the majority of the mess. Next we will use paper towels and 3M’s General Purpose Adhesive Cleaner to break down any excess goop. Alternatively you can use acetone or mineral spirits as well. The trick is to make sure and do a final wipe using a clean paper towel and some solvent to remove any residual sealant, cloudiness or hazing. This last step will give it that professional, clean look. With bare wood surfaces or on non-skid it may be a good idea to tape off around the hardware to ensure a neat finished edge. DO NOT wait until these sealants have cured as this will surely result in a less desirable look and is more difficult to clean up.
As much as I hate to say it, we do on occasion need to use a marine grade silicone sealant. The reason that, “I hate to say it”, is because silicone has to be the most overly and most inappropriately used product in the hands of boat owners today. Silicone is only to be used for final touches before stepping a mast, i.e. any open electrical holes, cotter pin legs, or ring dings. We will also use use a small amount of silicone and 3M electrical tape to seal the upper ring of a mast boot (as pictured above). If you are sure that you need to use silicone sealant, and it is in the proper application, make sure that it is marine grade… household silicone will not work and may rot and mildew.
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