Ten Genius Things You Can Do With A Glue Gun - 7. Create A Mold In Seconds Do you like to use polymer clay or maybe you do cake decorating. Did you know you can make molds for only pennies instead of expensive molding material. Squirt out a large dolop of hot glue and then push what ever it is that you want to mold into it. Wait for it to harden and you have your mold. It works best with smaller object because the glue cools quickly.