Bob, I have used a material that I bought in a hardware store. It's called "WATER PUTTY". water putty is a little tricky to use so don't mix up much at a time because it starts drying as fast as its mixed. If you use it test first so that you will know the drying time. I've used it and it held very well, better than anything else. Its also great to repair when you have to repair plaster with drywall. Good Luck, brAin