Magnum Steel 5-Minute Steel Epoxy Putty Magnum Steel This two-ounce tube is named Magnum Steel, which sounds like a TV series but is actually an excellent gray (steel-colored) epoxy putty that sets "like steel" in 5 minutes and fully cures in an hour. Works on metal, plastic or wood and can be drilled, sanded, painted, machined or tapped. Made here in America.