I recently purchased some Owens Corning pink rigid insulation foam from Home Depot for insulating a project I was working on at my office. This foam looks similar to Divinycell foams and looks like a foam that a guy might want to use in an airplane project, but looks can be deceiving, anyway about a week ago I picked up one of the left over pieces and decided to bring it to my house for a test. This particular foam has a thin layer of plastic on both sides of it. The plastic can be pulled/peeled off of it which I did. I took this piece along with a piece of divinycell foam and prepared the top surface of each with micro then placed one layer of unidirectional cloth down the length of each piece, then wetted out to finish with epoxy resin. I left the glass cloth sticking off of one end of each. My original thought process was to test compression of these pieces with one layer of cloth on both sides of each piece. After letting cure for at least a week I thought, what the heck lets just see what the peel strength is before I glass the second side of each. I took hold of the glass cloth overhanging the pink insulating foam first. It peeled right off of the foam very easily, as a matter of fact so easy that I was stunned. There was a thin layer of foam on the bottom of the cloth, I could see the micro and glass cloth through it. Next I took hold of the Divinycell piece and as I did I thought, well I wonder how easy this one will come off ? I am not telling a big one here folks, (even though I am from Texas and could) I could not get this piece of fiberglass to tear loose initially. I thought well lets get a better grip and pull much harder I did and it still would not even start to tear loose. I still can't believe the foam did not give up and shear off. I wrote about using Divinycell/klegicell foams back around 2000 or 01 if not before, comparing it's use to urethane foams in shear strength for wings and such. I can't really remember doing a test like this before but I can not be more impressed with Divinycell foam than I am right now. I will say that if anyone is planning on using the insulation foam I am talking about for airplane parts you may want to do some of your own testing before proceeding and then rethink that idea. I realize that Divinycell is a little more expensive but I believe without a doubt that it is worth the difference in money in order to make a much stronger airplane for yourself. I have used the divinycell foam for my (KR2 stretch) floor and seat back and plan on using it for wing ribs and probably wing surfaces. I can stand up in my KR2 and jump up and down on the floor and nothing happens (like falling through). I will be able to place a foam cushion right on my floor and sit on it without worrying about falling through the bottom of the airplane. I built my KR boat in about 1990 maybe a little before and then had it in storage all these years until recently. I am now trying to gear myself up to finish this little plane. Larry H.
