epoxy over gelcoat

Discussion in 'Fiberglass and Composite Boat Building' started by Crayolo, Apr 11, 2019.

  1. Crayolo
    Joined: Apr 2019
    Posts: 2
    Likes: 0, Points: 1
    Location: France

    Crayolo New Member

    Hello,

    The shower room is in plywood from bottom to top. I don't own exactly a boat, it is a van instead. But I hope nonetheless you could help me.

    Unfortunately, the craftsman, so-called professional, laminated the plywood directly with gelcoat (roughly), without any resin before.

    Now, I don't think I could put resin over the gelcoat, will it stick? Is there a way to fix the damage?

    Thank you.
     
  2. Dejay
    Joined: Mar 2018
    Posts: 212
    Likes: 20, Points: 18
    Location: Europe

    Dejay Senior Newbie

    Someone correct me if I'm wrong, I'm just learning too.

    If you sand to rough up the surface epoxy should stick just fine. If you want a really smooth surface you need to sand multiple times anyways, so this might not be a bad thing to fill up the wood surface a bit. Or you could sand it off completely.
    But you might consider a bit of light fiberglass cloth to make the surface more durable, cracks or dings might be a problem with water ingress.

    You have some pictures of your van build? :)
     
  3. Blueknarr
    Joined: Aug 2017
    Posts: 469
    Likes: 65, Points: 28
    Location: Colorado

    Blueknarr Senior Member

    Welcome to the forum.

    Pictures always help. I don't know exactly what you're trying to fix, other than it is a rv shower.

    Is the surface simply too rough?
    Are there cracks in the corners?
    Are there cracks developing along the plywood's grain?
    Are chunks of gelcoat flaking off?

    Quick answer is epoxy will adhere to gelcoat. However, the gelcoat is a weak link. So it is advisable to remove the gelcoat/paint prior to an epoxy repair
     
    Last edited: Apr 11, 2019
  4. Crayolo
    Joined: Apr 2019
    Posts: 2
    Likes: 0, Points: 1
    Location: France

    Crayolo New Member

    Thank you a lot!
    I think I'll try and sand it completely. I'll buy a sander tomorrow. Thereafter, I would be able to put some resin into the plywood as it ought to be if I am not mistaken, fiberglass cloth and so on.

    I have no pictures tonight, maybe tomorrow :)

    Thank you.
     
  5. Blueknarr
    Joined: Aug 2017
    Posts: 469
    Likes: 65, Points: 28
    Location: Colorado

    Blueknarr Senior Member

    So features to look for in sander.
    • Vacuum attachment (you don't want to breath the dust)
    • Coarse grit (50 grit or less)
    Your plywood may already be sealed
     

  6. trip the light fandango
    Joined: Apr 2018
    Posts: 161
    Likes: 24, Points: 18
    Location: Rhyll Phillip Island Victoria Australia

    trip the light fandango Senior Member

    It's mainly the end grain/edges of the plywood that is most vulnerable ,it needs to be thoroughly sealed. The corners are the area that need the most attention, they would normally be taped with fibreglass matt with a fibreglass putty worked into the corners first to avoid making the tape do a full right angle, air bubbles and creases are no good. Check out you tube for ideas. Once you put on epoxy the only thing that will stick is more epoxy so do it last, and it is very hard to sand. use polyester resin for taping. I'm guessing what your problem is though, pictures are needed really.
     
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