Repairing gelcoat to original color

Discussion in 'Fiberglass and Composite Boat Building' started by aaronhl, Feb 9, 2013.

  1. aaronhl
    Joined: Aug 2012
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    Location: Central Connecticut

    aaronhl Senior Member

    I had to repair some holes in my rc boat's gelcoat, filled/covered holes with epoxy and fiberglass from the inside and had to sand the outside to smooth. I am very happy with the way it came out, except for the color of the epoxy, I used barely any red paint in the mix and it changed to purple. Anyways, I think the only way to cover the damage now is to paint, but do you guys have any recommendations for restoring the original gelcoat without painting? And maybe keeping the dark repair showing or painting it, at least the painted area won't be as big in that case. The repair loos great when I wipe a wet cloth over it!!

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    What do you think?

    Aaron
     
  2. Herman
    Joined: Oct 2004
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    Herman Senior Member

    i THINK the boat is polyester with gelcoat. Which could have been touched up with colour matched polyester gelcoat. Which can still be done, but is a risk, as polyester gelcoat does not cure over every epoxy.

    Besides that, adhesion can be problematic, but for an RC boat it usually is OK.

    Mixing different chemistries is always a challenge. I honestly do not understand your mixing in of paint into epoxy. Chances are that strange things happen. (cure inhibition, etc)

    As for now I would sand the complete boat, then spray paint it in whatever colour you want. Rattle cans are good for that. Heat them up a bit in warm water (dry them off before painting), do a mist coat or 2, then a wet coat, and you are good to go.
     
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  3. aaronhl
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    aaronhl Senior Member

    Yes, the boat is polyester with gelcoat. I used West System epoxy resin and added paint as pigment as following the West System website to do so. http://www.westsystem.com/ss/adding-pigments-to-epoxy/

    Would car rattle spray paint work well? I would like to use gelcoat however I don't want it to be a thick cover of the hull.
     
  4. PAR
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    PAR Yacht Designer/Builder

    You can use a tie coat under the polyester gel coat on epoxy, which will improve the bond. If it was me, I'd just prep the surface and squirt it with a aerosol spray can, which will offer a nice, relatively light weight finish.
     
  5. aaronhl
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    aaronhl Senior Member

    Cool, any particular paint you recommend?
     
  6. PAR
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    PAR Yacht Designer/Builder

    Use one of the major brands, as these seem to work best. Of course surface prep is the key to a good paint job, so block it down and squirt away.
     
  7. Herman
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    Herman Senior Member

    Motip, Duplicolor, I have no idea what brands are available locally. Jump into a car accesoiries store, and pick a colour you like.
     
  8. dinoa
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    dinoa Senior Member

    What is a good primer for applying gel coat over epoxy? I never had any problems using MGS or Lesonal Vorgelat and Schwabelack gelcoats over epoxies. Not so with generic no names.

    Dino
     
  9. Herman
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    Herman Senior Member

    It is not really the gelcoat that is causing the problems, the epoxy is. I know some epoxy work well with polyester gelcoat on top, some epoxy inhibits the cure of the gelcoat.

    So a good primer can be a "friendly" epoxy.
     
  10. PAR
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    PAR Yacht Designer/Builder

    Again, or a tie coat over the epoxy for the gel coat . . .
     
  11. dinoa
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    dinoa Senior Member

    What would be a good tie coat?

    Dino
     
  12. PAR
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    PAR Yacht Designer/Builder

    There are several products to consider, including IMEDGE ECT 120, which is a epoxy gel coat that works without a tie coat. Dura-tech is a commonly mentioned brand, CCP and other manufactures offer a number of products.
     

  13. dinoa
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    dinoa Senior Member

    Thanks PAR
     
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