A method for shielding a metal substrate surface during the application of heat to the surroundings of the substrate which comprises. A liquid maskant composition is formed which comprises: a) at least one of a polycarbonate urethane diacrylate oligomer, a polycarbonate urethane dimethacrylate oligomer, a polycarbonate caprolactone urethane diacrylate oligomer, or a polycarbonate caprolactone urethane dimethacrylate oligomer; b) a reactive diluent capable of free radical polymerization; and c) a photoinitiator capable of generating free radicals when exposed to actinic radiation. The maskant composition is applied onto a surface of the substrate. The maskant composition is then exposed to sufficient actinic radiation to polymerize or crosslink the composition into a dried maskant. In use the dried maskant is heated on the substrate to a temperature of from about 400° F. to about 600° F. for from about 20 minutes to about 30 minutes, and then the maskant is removed.