Protection for Larch Gunnels

Discussion in 'Fiberglass and Composite Boat Building' started by Seano, May 24, 2010.

  1. Seano
    Joined: May 2010
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    Location: Ireland

    Seano New Member

    Hi,

    I am restoring an old 23ft fibreglass fishing boat. The old gunnels were made of ply and were rotten so we replaced them with some nice lengths of Larch. Having replaced the gunnels we decided to apply a layer of fibreglass matting in the hope this would increase the lifetime of the Larch. Primarily we want to prevent splitting of the timber and make it more durable for the workings of a small fishing boat.

    Unfortunately this is where things started to go wrong! The fibreglass matting didn’t absorb enough of the resin (HT9000+HT9002) despite of best attempts to roll it. The Larch seemed to absorb a lot of the resin and perhaps our fibreglass matting was too heavy duty. The result is some quite nasty looking fibreglass with many air pockets and other problems so it is very likely this will all have to be removed. L

    I would really appreciate any advice you can offer on how I could retreat from this failed attempt and then set out again to best protect the Larch gunnels. Is the Fibreglass approach at all viable? Or can you recommend any other methods?

    I would really appreciate any help....
     
  2. alan white
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    alan white Senior Member

    What are you calling gunnels? Please describe in detail whether they are applied to the outside, the top edge, or the inside, or you mean an assembly of several parts.
     
  3. Seano
    Joined: May 2010
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    Seano New Member

    Hi Alan,

    I am talking about the outside top edge. We attached the inch thick lenghts of larch on both sides of the boat and they ran from bow to stern in length. Each side got two lengths of the 1inch thick lengths of timber.

    thanks
    sean
     
  4. Herman
    Joined: Oct 2004
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    Herman Senior Member

    You discovered why you will need to prime the wood first, before attempting any glass work on it.

    Usually I am not too fond of polyester and wood combinations, but in this case it might hold, as a fishing boat is a heavily used boat, so the gunnels will need regular replacing anyhow.
     
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  5. Seano
    Joined: May 2010
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    Seano New Member

    Thanks Herman, would you have other recommendations to give the timber protection? perhaps I have taken a wrong route trying to fiberglass....

    Thanks again!
     
  6. Herman
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    Herman Senior Member

    Depends on how much abuse it will take. If there is a high risk of damaging the part, I would construct it in a way that it is easily replacable, or at least part of it.

    In general, wood is protected either by paint, varnish or epoxy. The latter can be glass reinforced, and needs a paint to protect the epoxy from UV. (could also be a clear paint with UV blockers).

    If you go the epoxy way, make sure it is protected all around, screw holes, etc.
     
  7. alan white
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    alan white Senior Member

    Given that there's not a lot of square footage of area to glass, I'd use epoxy (a quart would likely do fine). Polyester wouldn't save much money on such a small job and it won't last nearly as long. Glass tape will work best as the edges won't unravel and you can get it in 2", 3", 4", etc. wide.
    Then paint (buff, gray, etc.) will protect the epoxy and wood. You could also have used vinyl but it doesn't look as nice and colors are limited.
     
  8. Seano
    Joined: May 2010
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    Seano New Member

    Hi Alan and Herman,

    Just a quick note to thank you both for your help and advice. I have since removed the failed epoxy job and started again from scratch with a new epoxy coating and UV paint. This time I only used bandaging to cover the timber joints and edges (no glass matting). The job has turned out very nice indeed.

    Thanks again!
    Sean
     
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  9. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Good to hear, and than you for reporting back. Highly appreciated! Have fun!
     
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