A few minutes ago I asked my husband what is shim stock and he said he had no idea. I was like, really? He had no idea? I thought he knows about this thing because he does maintenance job. I think he was just kidding to me. I really have no idea about it, but if I am not wrong, this is made of high quality plastic. They use this to make gaskets and some other parts. Aside from that I do not know anymore I might check it online.