Systems Three Gel Magic?

Discussion in 'Fiberglass and Composite Boat Building' started by endarve, Jan 12, 2017.

  1. ebnelson
    Joined: Nov 2013
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    ebnelson Junior Member

    If it were me I'd definitely use fiberglass instead of just relying on the glue. You should read this, informal, test comparing laminating resin vs structural in coupon testing. Structural is better in the first test.

    http://jcrocket.com/adhesives.shtml

    More importantly though, read the second half of the test before making up your mind on how to proceed with the repair.
     
  2. M&M Ovenden
    Joined: Jan 2006
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    Location: Ottawa

    M&M Ovenden Senior Member

    Hi Par,

    I'm going to be laminating up some solid pine masts (11.25" dia x 60ft) and was looking at T-88 as the adhesive. I was wondering what you would suggest as a filler for this application if I wanted to mix up my own.

    Considering the need for a long working time I was considering going with the T-88 to help speed up mixing / assembly.

    Cheers,
    Mark
     
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    T-88 is costly stuff for the convenience, but some like this premix anyway. At normal room temperature, you only have about a half hour of good working time. At 40 minutes, you can feel it's starting to gel, but is still workable and you can push this for about 10 - 15 more minutes. Higher temperatures shorten this of course.

    West System 209 offers more time, about an hour at room temperature. There are other slow hardener formulations that are pretty good too.

    Use milled fibers as the primary filler, with silica to control viscosity. Add a touch of wood flour (pine in your case) to color the seams if you like, but make sure it's really flour, not sander shavings, which are a lot bigger particulates, than flour.

    Your epoxying mixing time will amount to a few minutes per pot, so not much of a time saver, particularly if you have a helper.
     
  4. M&M Ovenden
    Joined: Jan 2006
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    Location: Ottawa

    M&M Ovenden Senior Member

    Thanks Par, I thought it would be the milled fiber, but nice to get confirmation.

    Mark
     

  5. M&M Ovenden
    Joined: Jan 2006
    Posts: 349
    Likes: 74, Points: 38, Legacy Rep: 527
    Location: Ottawa

    M&M Ovenden Senior Member

    Hi Par,

    Can you give any guidance as to how much filler is needed for an adhesive application ? I'm looking at purchasing some RAKA epoxy + fillers and I haven't found any reference material as to how much filler is typically needed.

    I realized this isn't an exact science, but I'm just wondering how much milled fiber and fumed silica I should be ordering per gallon of epoxy. They sell it per pound and I'm trying to get a ROM on what I should order.

    Thanks !
    Mark
     
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