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Thread: Composite fiberglass/foam panel build question

  1. #81
    Join Date
    Dec 2017
    Location
    Kentucky
    Posts
    7
    Quote Originally Posted by rruff View Post
    But after seeing what Dow and OC sell for panel core material, I'm not worried. Dow has 20, 30, and 40 psi core, and list the 30 psi variant as being for vehicles.
    Are you located in the States?
    Have you been able to locate a dealer/retailer for the Dow Panel Core 20-30-40 XPS?
    Looks like O-C makes their PinkCore Tight Tolerance Board in 15-25-40-60 XPS.

  2. #82
    Join Date
    Sep 2009
    Location
    North Idaho
    Posts
    2,804
    According to Dows website...


    Distributor locations currently available in UK, Germany, France and Ireland only


    https://www.dow.com/en-us/building/c...dealer-locator

  3. #83
    Join Date
    Sep 2016
    Location
    NM
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    669
    Quote Originally Posted by stoneburner View Post
    Have you been able to locate a dealer/retailer for the Dow Panel Core 20-30-40 XPS?
    Looks like O-C makes their PinkCore Tight Tolerance Board in 15-25-40-60 XPS.
    As per Idasho, I guess there aren't any. The stuff at the hardware store is the same material, but the panel core sheets have been planed to tight tolerances. I've noticed the OC Foamular varies in thickness a bit, but I can deal with that.
    2016 Toyota Tundra SR 4x4 Double Cab Long Bed 5.7L..... DIY camper on the way...

  4. #84
    Join Date
    Jul 2010
    Location
    Foresthill, CA
    Posts
    311
    You can purchase both planed panels in the US, the only caveat is the volumes. I recall it was 60K SF. They are made to order special runs for both Dow and OC, and you don't have to get them in standard sheet sizes. They can do continuous length of close to 20 ft. The cost of those panels are almost double per SF vs standard "stamped" panels.

  5. #85
    Join Date
    Dec 2017
    Location
    Kentucky
    Posts
    7
    Yep. That's the usual problem. The high density XPS foams don't have high public demand so they're not usually stocked by Lowes, HD and retail lumber outlets.
    This last autumn I just discovered that HD in my area carries the Foamular 250 year-round.

    BTW some of the surfboard epoxies are quick setting (e.g. Resin Research).

    RR Kwik Kick:
    Ambient Temperature
    70F (21C) 80F (27C) 90F (32C)

    Pot Life
    18 min. 14 min. 11 min.

    Set Time - Tack Free
    1.5 hrs. 45 min. 30 min.

    2. UV stability is excellent with little or no discoloration in over 1000 hours.

    3. This system contains UV absorber which allows it to be used in conjunction with sensitive substrates. I.E. Urethane foam, PVC foam, light colored woods, etc.
    _____
    Last edited by stoneburner; 01-21-2018 at 07:39 PM.

  6. #86
    Join Date
    Dec 2017
    Location
    Kentucky
    Posts
    7
    OK, I reviewed this entire thread to make sure I wan’t missing anything.

    My interest in XPS is surfcraft construction (surfboards, body boards, etc.). Not soaking up water is a huge advantage for surfcraft when they get dinged while in use. XPS densities are similar to the PU foam used for traditional construction.

    Surfcraft take a lot of punishment in waves (often equivalent to class 4-5 whitewater). Surfcraft are also exposed to rapidly changing temperature extremes (hot sun – beach & car racks – then straight into cool-cold water). As much as 50 F temperature differential within a few minutes (expansion and contraction). Pressure dings on the decks from heels on take-offs (foam crushing: minimum compressive strength). All of this magnifies problems with delamination.

    Delamination is the big problem. Some builders claim no problem with XPS delaminating. Others report the XPS delams almost immediately. My observation has been that those who report instant delamination are using XPS with 15 psi min. comp. strength.

    Some of those who report successful use of XPS swear by cleaning the (printed) surfaces of retail XPS with high purity denatured alcohol first, before doing any other surface work.

    I found 3M 78 adhesive bonds XPS sheets well if you don’t need to sand or hotwire bonded seams of foam. However, to get max bond strength, I had to let the bonded sheets cure for 2-3 days.

    The following is some of the useful information I gleaned over the past several years:

    Regarding strength for internal 90 degree joints, a fillet of epoxy/flocked cotton (flox) can be used as a fairly cost effective way to strengthen the fiberglassed internal surface of the joint. For a chemical bond, the epoxy-flox mix needs to be applied before the epoxy cures. Amine blush on epoxy cured in humid environments will affect bond between epoxy coats.

    Regarding composite sandwich construction, an engineer who manufactured EPS surfboard blanks told me, “Fiberglass and other composite skins should be viewed as surfaces rather than part of the core. The composite skins are minimizing parallel surface movements relative to the core.”

    Regarding stiffnes/flex, I played with building longboard skateboard and mounatinboard decks. Stiffness significantly affects performance. The critical lesson for me was, “Stiffness is directly proportional to the cube of thickness.”

    Regarding bonding of materials, material surface energy is the determining factor. All compounds with surfaces have their own unique surface energy value (polyethylene = 32; polystyrene = 34; 6,6 nylon = 42; glass = 250-500; etc.). The take away is that epoxy adheres better with solid surfaces that have surface energy values equal to or greater than 45 dyne/cm.

    Where I am going next with WPT perforation is orientation of perforation slits/cuts relative to the axes of flexing.

    I have been determined to make retail XPS a viable core material for surfcraft. I am fairly confident I have found my answers. My next build, when weather warms, should be the final proof.
    Last edited by stoneburner; 01-21-2018 at 07:53 PM.

  7. #87
    Join Date
    Nov 2009
    Location
    near detroit
    Posts
    1,018
    Thank you very much for sharing all this !
    Cheers,
    Frank

    ____________________________________________

    "airsotts-narf"

    Save a Life, Adopt !

    Redline wrote: "no ring, no bling, bada-bing" ( http://roadtraveler.net/goodbye-bling-rings/ )
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