Transom coating

Discussion in 'Boat Repair Help' started by justwannano, Jun 13, 2009.

  1. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    I replaced the transom in my 14' Polarcraft last year and did it again this year.
    I just raised it 3" this time.
    I noticed last year that I had a couple of small leaks and was wondering if I should coat the outside aluminum to seal it.
    Right now I'm thinking pickup bed liner.
    Ideas or advice Please.
    thanks
    have a good 1
    just
     
  2. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    Maybe I'd better explain a little more just what I'm dealing with here.
    There are a couple of problems that I ran into with this transom replacement.
    The 1st and probably most serious was a flaw in original construction.
    Who ever drilled the holes originally in the factory didn't line up the inside support bracket with the hole he drilled outside the boat.
    It wasn't a terrible problem because the aluminum rivet head just bent to fill the void. Now here comes I putting a steel bolt in that hole so the head of the bolt doesn't sit flat on the aluminum transom.
    I can see bolt threads. I don't especially want to drill it straight thinking the less holes in a boats hull or support bracket the better. Any way I need to seal that space.

    There are some other problems. Some other holes are also present. Because of the wood transom I have installed and the wood piece that protects the aluminum from motor support damage, the filler to fill that void can only be as thick as the boat hull itself. So something like bondo is out.

    Also the genius that owned the boat before me thought he did not have to have a licence for a trailer he borrowed because he bolted a trailer licence plate to the transom. So I've got those to fill.

    Also and finally I don't want to make this transom permanent/permanent. Because the engine I have is old and maybe won't last many more years I may need to put the transom I made last year back in. I really want a short shaft motor like the boat was designed for.

    Clear as mud?

    Thanks for any advice
    just
     

  3. Iowa_Josh

    Iowa_Josh New Member

    Messages:
    1,463
    State:
    Central Iowa
    The boat repair gods say get some 3m 5200 and you can rivet on an aluminum patch if it needs it. Pop rivets aren't waterproof but you can use them above the waterline and/or smear with some of the 5200.
     
  4. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    Thanks Josh.
    I'm kinda in a quandry about what to do with this boat.
    When I first posted this thread I was thinking just coat the entire transom. Something sprayed or painted/rolled on.
    Now I just don't know for sure what to do.
    Maybe just patching it is best.
    ??????????????????????????????????:confused2:

    Anyway thanks for the info
    just
     
  5. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Truck bed liner aint a patch.
    3m 5200 is damn near permanent. You burn that stuff off with a torch.
    But if you got it, use it.

    Otherwise go with 3M's 4200. In both cases I would use the fast cure.
    It's a one part polyeurathane "caulk".
    There is a solvent release for the 4200. It's tough as nails but it's not as permanent as 5200 is.

    To give you an idea how strong 5200 is.
    I've seen outboards that have been caulked around with 5200 to seal the motor to the transom. When the motor was removed so was the fiberglass skin that was laminated to the transom wood.:big_smile:
     
  6. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    Thanks Mark.

    I was thinking about the possibility of the bolts not sealing. Since there are 42 bolts the possibility is pretty good something is gonna leak. Twelve of the bolts do not have their heads to the aluminum transom but on the plywood (backer?) that the motor clamps to so I also have a wood to aluminum to wood to aluminum brace seal problem to deal with.

    Will the 4200 be stiff enough to fill a 1/4 " hole in the aluminum if it is flush on the outside with nothing on the back of it on the inside?

    Maybe I should just stick a pan head bolt in the hole(s) and tighten ??

    :confused2:

    Thanks for the info
    just
     
  7. DANZIG

    DANZIG New Member

    Messages:
    6,672
    State:
    West Virginia
    I've filled holes with SS bolts 'n' nuts and a touch of sealant, rivets, and JB weld. All have worked fairly well.

    This go round, I am going to give HTS 2000 brazing rods a try.

    Mark had a couple of posts on them a while back. Perhaps he will share his "long term" experience with them.