Larry, The Nidacore itself is polyethylene, with a polyethylene surface, onto which a non-woven polyester is bonded for adsorption of the resin. Just a guess, but I would use a vinyl or polyester resin for the fiberglass over the surface. As for glassing the backside, I think not necessary for the wing skins. I was writing about using them for stub ribs, do I would cover on both sides. Yes, Lastafoam is light, but this Nidacore is even lighter.
Your comment about adhesion is well taken. I purchased a front deck from Jack Dougherty, made by RR in the early days of the KR-100 (? Maybe). It has some kind of honeycomb inside of it, and through years of storage by Jack, and transporting and moving around in my hangar, it's still bonded properly. It looks and feels like epoxy, not an ester resin. Divinycell foam is PVC based, will not work out with a vinyl ester foam. Important is you are putting in wing tanks. It weighs only about 10% more than Lastafoam, but costs almost twice as much. I have no info about how easy it is to sand. On my first project, I designed and built wingtips with PVC foam from a boat supplier, using epoxy, not ester resin. My intent was to make them into tip tanks by dissolving the PVC with lacquer thinner. That plan would have probably given me trouble, knowing what we now do about gasoline's effect on epoxy tanks. I did make my original header tank on that old project, using vinyl ester and Clark foam. It turned out to have a 17-gallon capacity! Saved for eternity in Steve Bennett's KR Quarterly, 1986. I have the Diehl wing skins already installed on my current project. The complete wings weigh 38 # each. That weight doesn't include the stubs. I have no doubt that skins are heavier than sanded foam, but the Diehl skins save a lot of work, and are less prone to surface imperfections (loss of lift or increased drag), Because they are a sandwich, and not glassed on only one side. Griff P -----Original Message----- Sent: Thursday, October 17, 2024 9:00 AM Subject: KRnet> Nidacore panels questions? What is the adhesion characteristics of the resin to Nidcore as it is "plastic"? Could Nidcore be covered one side only as is done with the foam on the wings. If I were to use Last-o-foam to build the wings, 1/2" covered one side only as plans call for, (I think I used 1" 30 years ago) , weight of one cubic foot translates to 4.5 pounds per 24 square feet of wing area. That should translate to about 10 pounds per wing or 20 pounds total for the wings. That seems high for some reason as I recall a 2'X8' sheet seemed to weigh very little. What about Divinycell foam? reasonable price? https://fiberglasssupplydepot.com/divinycell-pvc-foam-core-h-80-5lb-density-plain-sheet.html?attribute_values%5B300%5D=1299&gad_source=1&gclid=CjwKCAjw68K4BhAuEiwAylp3klZ_W6LL-hNZ6kxusqe7DKyawrySS9Jr-N3B2hVS1AnXfamnUmi5-xoC9PcQAvD_BwE#product-details-tab-description Prices have sure gone up in the last 30 years. 🙁 Larry Flesner -- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnet -- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnet
