How to fix air bubbles in fiberglass

Discussion in 'Boatbuilding' started by mariobrothers88, May 20, 2021.

  1. mariobrothers88
    Joined: Sep 2020
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    Location: San Diego, CA

    mariobrothers88 Senior Member

    Hi guys, I laid down 2 layers of 17 oz biaxial fiberglass on the chine and keel joints and a third layer of 10 oz plain weave fiberglass and epoxy. I noticed some air bubble formation the next day particularly at the interface between the biaxial fiberglass and plain weave fiberglass due to the height of the biaxial fiberglass (see photo). What is the best way you guys would recommend to fix these air bubbles and how would you recommend to prevent these air bubble formations in the future? I did it all in one day, wet on wet process and I put down layer of epoxy first.

    My plan was to use my multitool or a razor blade to cut out the fiberglass over the air bubble and lay down a tiny patch of fiberglass/epoxy.

    Thanks for all the help guys!
     

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  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    That sounds like a good plan.
     
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  3. Blueknarr
    Joined: Aug 2017
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    Location: Colorado

    Blueknarr Senior Member

    Your correction is correct.

    Prevent by using some thickened epoxy as a ramp at the edge of the heavy cloth.
     
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  4. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Fixable two different ways.

    1. Grind out and replace with milled fiber and cabosil 50/50 and epoxy. About 2:1 solids to epoxy.

    2. Get snub nose injection needles 1/16", drill two holes at the top of each bubble and inject epoxy.

    bk advice is solid...I will add to make sure substrate is well consolidated in original lamination and sanded enough for follow on layers and use a 2-4" trowel with epoxy thickened with fumed silica for high ridges..this does happen on big jobs...do not allow; especially on bottom of hull to waterlines as they can result in hydraulic delamination (grows with water pressure).

    Also, for multiple tapes, stacking the edges is not allowed, so if you have multiple tapes, the edges must be stepped.

    I never glass over unsanded tapes for this issue.
     
  5. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    So, leaving the screws in?
     

  6. mariobrothers88
    Joined: Sep 2020
    Posts: 132
    Likes: 6, Points: 18
    Location: San Diego, CA

    mariobrothers88 Senior Member

    Yes per Richard Woods.

    Thanks for all the advice guys I really appreciate it!
     
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