Marine Sealant

Discussion in 'Boating' started by JPritch, Feb 28, 2007.

  1. JPritch

    JPritch New Member

    Lynchburg, VA
    Wondering if you all have any recommendations for a good marine sealant/caulking to use for installing my Lowrance transducer? The owners manual is not specific at all as to which type I should use other than "high-grade".

    I did a little research, but not sure if I need something strong like 3M 5200 (polyurethane) which they say is pretty much permanent, or a polysulfide formula, or a weaker silicone based formula.

    If it helps, I do plan on replacing my sonar down the road.

    I also found a thread where a guy was saying you should fill the drill holes with epoxy first to help prevent transom rot, then install the screws and then apply sealant. Any merit to this method?
  2. trnsmsn

    trnsmsn New Member

    Missouri Originally Now I
    Don't be afraid to use the 5200, they make a chemical that will release it, if need be.

  3. Mark J

    Mark J New Member

    Four Oaks, NC
    3M 4200 is for the nonpermanent applications.

    As far as epoxying holes thats done like this.

    If you need a 1/4" hole you would drill atleast a 3/8" hole. Fill it back up with thickened epoxy. Once its cured drill your 1/4" hole through the center of the epoxy plug.
    That method is the only method that will assure no rot. The wood is totally sealed.
    Dont worry about an epoxy plug coming out. You'll put 3 transoms in it first.
  4. Bobpaul

    Bobpaul New Member

    Supply NC
    Not many people fill a larger hole then drill a smaller one in the filled area just for a screw. For something larger, like a thruhull fitting, it is recomended.

    Not many boat manufacturers even do it. They'll seal the fittings with 5200.

    All screw holes should be sealed with the 5200 and coating the screws before you insert them is a plus. Clean up excess 5200 with acytone for a finished job.