Marine Sealants
Babyboomer
Member Posts: 918 mod
At some point working on a boat will provide you with the challenge of determining which sealant to use. After all the marine environment is a harsh one and depending on where the sealant is to be applied will determine the proper one to use. Hopefully this tidbit of information will help you decide on what you need to do the job.
Silicones - have more flexiblity and generally less bonding strength, they work well as a seal between objects that squeeze or rely on compression (like a gasket). Silicones retain their flexibility for long periods of time and work wellon plastics. They do not work well below the waterline and cannot be painted. 3M Marine Silicone is an example.
Polysulfide Sealant - synthetic rubber that retains its flexibility yet has a tremendous ability to bond to anything including you and is very messy. Once cured it can be sanded and painted and makes an excellent caulking compound. It can be used on wood, metal, fiberglass but cannot be used on plastics, plexiglass, lexan, PVC or ABS. Polysulfides have a long cure time of a week or more. Life Caulk by Boating Life is an example.
Polyurethane Sealants - should be used when you need a more permanent bond. These sealants are more like an adhesive than a caulk. They are excellent for below the waterline use such as thru-hulls, however like polysulfides do not use them on plastics, plexiglass, lexan, PVC or ABS. Cure times vary depending on the product but average 3-7 days. 3M 5200 is an example.
Sikaflex Handbook
Tips & Tricks
- To leave a clean line when applying sealant in a visible area, first line the area with 3M Blue Painters tape, apply the silicone, remove the tape before the sealant dries.
- Apply a coating of Windex to your finger if you are going to use it to smooth sealant, this will help keep the sealant from sticking to your finger and make a smoother seam.
Silicones - have more flexiblity and generally less bonding strength, they work well as a seal between objects that squeeze or rely on compression (like a gasket). Silicones retain their flexibility for long periods of time and work wellon plastics. They do not work well below the waterline and cannot be painted. 3M Marine Silicone is an example.
Polysulfide Sealant - synthetic rubber that retains its flexibility yet has a tremendous ability to bond to anything including you and is very messy. Once cured it can be sanded and painted and makes an excellent caulking compound. It can be used on wood, metal, fiberglass but cannot be used on plastics, plexiglass, lexan, PVC or ABS. Polysulfides have a long cure time of a week or more. Life Caulk by Boating Life is an example.
Polyurethane Sealants - should be used when you need a more permanent bond. These sealants are more like an adhesive than a caulk. They are excellent for below the waterline use such as thru-hulls, however like polysulfides do not use them on plastics, plexiglass, lexan, PVC or ABS. Cure times vary depending on the product but average 3-7 days. 3M 5200 is an example.
Sikaflex Handbook
Tips & Tricks
- To leave a clean line when applying sealant in a visible area, first line the area with 3M Blue Painters tape, apply the silicone, remove the tape before the sealant dries.
- Apply a coating of Windex to your finger if you are going to use it to smooth sealant, this will help keep the sealant from sticking to your finger and make a smoother seam.
Slip 866 Sunset Marina Byrdstown Tn
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