Thanks John. I did check to make sure it was the polyurethane. I have built probably 20 sets of foam core wings back in the 80's and early 90's when I flew a lot. I had a piece of slate from a pool table to build on then and made some weights. I remember that part, I didn't enjoy it but I remember it. I'm going to look into a bagging system later on I think because I beleive that is the way to go from what I've read. I'm going to be building more in the future so I appreciate the help this forum gives.