Gorilla Glue is a non-toxic, solvent-free polyurethane glue. Natural glues like white glues (e.g. Elmer’s glue) or mastic are optimal, but this glue is much less toxic than most. It works well on wood, but it’s not as specific as most wood adhesives. It bonds pretty well on metals, stone, ceramics, and many plastics. It is waterproof, meaning it doesn’t break down when wet, and doesn’t expand or contract with temperature. You do have to clamp stuff in place for a while while it dries, which you should do with any glue. If you glue infrequently, it is nice that Gorilla Glue has a long shelf life — three years as opposed to one, as with many other polyurethane glues. It’s available from: Amazon ($13 for 8 0z), and most hardware stores. Review via Cool Tools.