How to Fiberglass a Boat

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Fiberglass is used to build boats for many reasons. Chief among these are its durability, but also its easy to repair. You can patch boat holes in an afternoon and fiberglass a boat in just a couple of days. This article covers how to fiberglass a boat using epoxy resin.

Steps

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  1. Before you begin the process of applying fiberglass to your boat, you need to prepare the boat. There are several preparations to consider.
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    After about 30 minutes, the solution should be significantly hardened and ready to apply to the hull of the boat.
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    This first coat is called the seal coat. Using a foam roller, apply firm pressure and directional strokes to spread the resin as evenly as possible. Wait for the surface to no longer be tacky before doing additional work on the hull. [3]
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    Cut fiberglass cloth to the shape needed. [4] Attach the fiberglass cloth to the hull using tape, tacks or staples.
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    This coat is called the bond coat. If you have waited for a while, consider sanding the hull again. Working from one end of the hull to the other, apply the bond coat over the fiberglass cloth. Remove the material you have used to attach the fiberglass cloth to the boat before the bond coat sets up completely. [5]
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    This coat is known as the fill coat. Wait for the previous coat to set up hard. If you have waited a significant period of time, clean and sand the hull again. [6]
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    The finish coat should be smooth and even, but should also be thick enough to allow you to sand the hull evenly without damaging the cloth.
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    Give the final coat enough time to dry, preferably overnight. Use lower grit paper at first and finish with a higher grit paper.
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    This can be paint or another boat hull finish. Apply the protective agent according to the package directions.
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Community Q&A

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  • Question
    I have accidentally drilled a 3mm hole where the boat goes on the skidbar; how can I repair it?
    Community Answer
    Clean the hole, rough up around hole, and fill with dowel rod sand. Go over with a fiberglass mat and resin.
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  • Question
    What is wrong if my fiberglass resin is still tacky after several days?
    Community Answer
    Probably not enough hardener, or the hardener was mixed in unevenly and you had some portion of the resin mix that has no hardener in it. You might have to grind it off and start again or get it out using solvent. Another reason might be temperature. It’ll need a certain amount of heat to cure. It’ll take a long time to cure in the cold.
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  • Question
    How do I repair an old fiberglass boat transom?
    Community Answer
    Cut out the inside wall, remove wood, clean out debris, cut new wood to size, install fiberglass mat, and resin several coats.
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      Tips

      • Work in a shaded, dry area, preferably with a temperature between 70 F and 85 F (21 C and 29 C).
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      Things You'll Need

      • Dewaxing solvent
      • Belt sander
      • Mold release
      • Fiberglass cloth
      • Fiberglass resin and hardener
      • Protective agent

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      References

      1. ↑ https://www.familyhandyman.com/automotive/how-to-repair-fiberglass/
      2. ↑ https://www.fibreglast.com/product/fiberglass-repair-composite-repair/Learning_Center
      3. ↑ https://www.glen-l.com/how-to-fiberglass-a-plywood-boat/
      4. ↑ http://www.boatus.com/boattech/casey/fiberglass-repair.asp
      5. ↑ https://www.epoxyworks.com/index.php/fiberglassing-a-woodstrip-hull/
      6. ↑ https://www.epoxyworks.com/index.php/fiberglassing-a-woodstrip-hull/
      7. http://www.glen-l.com/methods/how-to-fg.html
      8. http://www.boatus.com/boattech/casey/17.htm

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