Gelcoating transom

Discussion in 'Materials' started by MassimilianoPorta, May 12, 2019.

  1. MassimilianoPorta
    Joined: Apr 2019
    Posts: 58
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    Location: Italy

    MassimilianoPorta Junior Member

    Hi, I need to reapply gelcoat to the transom of my rhib.

    I can't spray it so I am limited to brush or roller, what would be the best?

    Second, as I know a lot of sanding will be involved, I want to apply many layers. How much time I need to wait between each layer?

  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    This can depend on the size of the area. On a smaller surface, if you use good techniques, and work slowly, it is possible to brush it and get it to level a little better than you may expect. This takes time though, and on a large area can be difficult.

    Rolling leaves a great deal of texture, but you can get around it by using a squeegee (plastic bondo spreader) after it gels and squeegeeing more gel coat on the surface. This fills the low spots and adds nothing to the high spots. You may need to do this a couple of times.

    As far as timing, you can still bond to unwaxed gel coat for a couple days. Sooner is better, but the surface will stay tacky enough for the next layer to stick well. Contamination of the surface may come into play if you wait though.

    The ambient conditions will play a big roll in this. Cool, humid and in the shade, and you’ll have the longest time period. Dry, hot and in the sun, and the time frame will be reduced dramatically.

    As to how soon you can apply the next coat. Just wait until the current layer hardens to the point that you can touch it and it doesn’t easily come off on your finger.

    The exact gel coat you buy will also have an influence on how well it lays down, some places even sell gel coat designed for rolling and brushing. Its not a great deal better, but it does help.
    Last edited: May 12, 2019
    MassimilianoPorta likes this.
  3. MassimilianoPorta
    Joined: Apr 2019
    Posts: 58
    Likes: 3, Points: 8
    Location: Italy

    MassimilianoPorta Junior Member

    The area is about 60 x 20 inches.
  4. Emanuel.M
    Joined: Jul 2019
    Posts: 1
    Likes: 0, Points: 1
    Location: ftlauderdale florida

    Emanuel.M New Member

    hi masters im looking to re gelcoat a 1981 whaler 15 footer it hs lots of spiderracks is there afiller for them or will the gelcoat cover it should i prime before gelcoating ? whats a good brand of gelcoat im looking to do this myself im a home painter never used gelcoat before any tips for a fute captain here ?

  5. KD8NPB
    Joined: Mar 2018
    Posts: 137
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    Location: South Carolina

    KD8NPB Senior Member

    Gelcoat does not need primer. The surface should be sanded with 220 grit and wiped with acetone before spraying.

    Cracks should be ground out with a grinder and filled with a fiber reinforced putty. Then, the putty needs to be ground down so the putty is slightly lower than the gelcoat, that way when you go to sand down and polish up the gelcoat, the repair area doesn't become thin.

    An ISO/NPG chemistry gelcoat should be utilized for best results. Gelcoat is air inhibited, so it is important that the last coat of the gelcoat contain a surfacing agent, such as Duratec High Gloss, PCU Patchaid, or wax solution in order to force the gelcoat to cure fully when exposed to open air.
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