Just when I thought I was done with this experiment I had another idea. I glued a heavy weight paper to the back of the copper using poly urethane glue. The paper is the same type used in the underpayment of a wood. The paper bonded great to the copper. So the next step is to bond the copper/paper layup to fiber glass and wood, just like a ski, and see if it all holds together. If this works I may get a copper ski before the ski season is over.
Depending on how thick the paper is, you might just be passing the issue down into the paper. It may well bond to the ski, but delaminate over time. One option would be to use a peel ply and bond during a secondary process or replace the paper with something a little more stable like a wood veneer. The car industry uses poplar/tulip wood veneer for this purpose.
Thanks Rich. The failure didn’t occur until I started bending/twisting the copper layups, probably flexed it more than any ski might experience but can’t take the risk of it delaminating on a buyer. I think under normal use, like for a counter top or as a decorative trim the bond would be fine.