Another balsa core thread with questions

Discussion in 'Fiberglass and Composite Boat Building' started by aaronhl, Jan 11, 2017.

  1. aaronhl
    Joined: Aug 2012
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    Location: Central Connecticut

    aaronhl Senior Member

    What should I thicken epoxy resin with when placing core down? I don't want to use wood fibers. Should I just get several cartons of the West System 403?

    I have bare fiberglass in the boat now, should I put a WET layer of 1708 type fiberglass down and while wet set the WET balsa? And then finish with another WET layer of 1708 to cover the balsa? Basically finishing the whole sandwich in one cure?

    Which side of the 1708 faces the bare hull and which side faces the balsa?

    Any expert knowledge to share about this installation?
     
  2. upchurchmr
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    upchurchmr Senior Member

  3. jorgepease
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    jorgepease Senior Member

    why not wood sawdust? That with some cabosil. I would wet out the core with straight epoxy first since that is going to suck it up. Much cheaper than buying a pre mix.
     
  4. upchurchmr
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    upchurchmr Senior Member

    This is the next most expensive method of boat building, and you want to cut corners on one of the cheapest details?

    If you want to do this, make some test panels first and break them.
     
  5. aaronhl
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    aaronhl Senior Member

    I will get in touch with them to see what would be a good epoxy thickener for installing the core.

    What "cheap" detail are you talking about? I can't make test panels until I have the right thickener.
     
  6. upchurchmr
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    upchurchmr Senior Member

    The filler jorgepease was suggesting not buying.
     
  7. jorgepease
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    jorgepease Senior Member

    The next most expensive method of boat building? What on earth are you talking about. Also are you saying West Products because they cost a lot are better than wood filler and cabosil? Because I don't know any professional boat builder using West Products.

    Last question, it sounds like the OP is re-coring a boat, if that is the case then he should be infusing or at least vacuum bagging.

    Whatever, go for it!
     
  8. aaronhl
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    aaronhl Senior Member

    Ah yes I do not want to use wood as a filler. I am already using it for the core and the floor so that is enough
     
  9. jorgepease
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    jorgepease Senior Member

    lol, yes good reasoning man. Happy Boat Building
     
  10. upchurchmr
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    upchurchmr Senior Member

    Next most expensive - Balsa core, then foam core.
     
  11. redreuben
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    redreuben redreuben

    Don't use wood filler it's gluggy crap and totally unsuited to the job at hand, use a blend of micro balloons and cabosil, if this is unfamiliar to you buy the West blend they recommend. If you are not vacuum bagging wrap the base of an orbital sander in plastic and use this to vibrate the material into the core.
     

  12. endarve
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    endarve Junior Member

    I used the WEST to thicken approx 50 gals of Reichhold epoxy. It works but takes a large amount to make it buttery. Plus WEST is way expensive compared to others. 2 parts filler (volume) to 1 part resin is what I do. If the resin stays wet a long time it will separate from the filler, which is what fumed silica (cabosil) does too. WEST originally used to call the product cotton/linen fibers and now its called microfibers. Either way its cotton fibers. Very easy to work with and not hostile for sanding. There are some who say the cotton absorbs water but I can't say either way. It's friendlier than fumed silica health wise but is way expensive in comparison. I don't use the cotton anymore because I can buy a bag (the size of a large pillow case) of fumed silica for
    $75. Also, other companies sell cotton filler and the savings are large.

    I would suggest pre-coating the balsa end grain and let it tack before glassing. Otherwise the balsa may suck the resin out of your cloth and leave a dry laminate.
     
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