Looking for a good filler/fairing compound for repairs

Discussion in 'Materials' started by gtcway, Feb 4, 2015.

  1. gtcway
    Joined: Dec 2004
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    Location: Bahamas

    gtcway Junior Member

    I do a bit of boat repairs involving gelcoat. I also paint boats with Awlgrip and always use epoxy fillers when painting.
    When it comes to gelcoat repairs, it depends on the location and customer but I use anything from 3m premium marine filler (expensive), auto lightweight filler (don't like to), to homemade fillers using polyester resin, microballoons and cabosil.
    I would like to be more consistent with using a better quality filler. Does it make sense to make homemade with vinylester resin? If so, is there any way to do it with a cream hardener for faster cure time and easier mixing of hardener?
  2. pescaloco
    Joined: Feb 2006
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    Location: so. california

    pescaloco Senior Member

    I like the 3M Vinylester filler for gelcoat repairs
    Yes it's expensive but you can't beat the BPO hardener for speed of cure
    For big stuff I mix balloons / cabosil AND talc for fairing putty
    You could also check out RJ fairing putty for a good premixed one MEKP catalyized

    Maybe some one will pipe in but I have never heard of BPO cream hardener being used with a regular poly/Vinylester laminating resin
  3. gtcway
    Joined: Dec 2004
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    Location: Bahamas

    gtcway Junior Member

    Is talc okay to use below the waterline?

    As for the cream hardener, it was just an idea I had to make it easier when mixing my own fairing compound. I guess I can catalyze before adding the fillers, but thought it would be a real time saver to premix larger quantities of fairing compound to use as needed. As everyone knows, it's much easier to know you're thoroughly mixing cream hardener with a thick paste vs. a small amount of clear liquid.
  4. FishStretcher
    Joined: Oct 2011
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    Location: On the Water

    FishStretcher Junior Member

    My experience with making my own vinylester fairing compound is that fresh resin has a shelf life of 3 months. If I have fresh resin, I can have a 10-20 minute pot life at 85F and 1.5% MEKP. This starting with a very thin" infuison grade resin. I spend the first 8 minutes or so mixing in the fumed silica and microballoons, after catalyzing the batch and this works well. Getting enough silica mixed in well enough, fast enough is a challenge for a larger batch. I do seem to err on too little silica and too much microballoons, typically. I wonder if one could premix the silica in the resin prior to catalyzation.

    I haven't tried the 3M product, but want to.

    I see you are in the Bahamas. I wonder if keeping the very reactive vinylester fresh is part of what drives your experiences? I store mine at 55-60F in the dark corner of a basement, and it is a very fast resin. I generally have too little pot life, not too much.

  5. gtcway
    Joined: Dec 2004
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    Location: Bahamas

    gtcway Junior Member

    I wouldn't mind premixing my own with polyester resin on some jobs, if there was a way to have it harden using cream hardener.
    I've never used vinylester resin for laminating. It's not available here, probably because it sets so fast. I only use polyester or epoxy.
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