This is a long shot, but does anyone know where I can get a piece of hard plastic that would be at least 1 inch thick, by 3 inches wide, by 5 feet long? I need to make a shim to go underneath a sliding shower door for a full sized tub. My husband made one out of oak, but we have found that even with the tub caulk, water seems to find a way in and is causing the wood to get wet, and then leach a brownish substance back out around the caulk. I've removed the caulk and the bottom of the frame, but need to make a new shim. I'm thinking I could make it out of some sort of rubber/plastic, semi rigid, that could be cut with a table saw? Any ideas?

