Versachem Inferno Metal Repair is a thermally-stable adhesive designed to weld cracks and holes in metal surfaces. Use it to repair manifolds, mufflers, catalytic converters furnaces and more. Works best on metal, metal substrates, cast iron, and steel. Air dry for 3-4 hours, gradually heat repair for 10-15 minutes to complete cure using a heat gun capable of attaining 350°F to 400°F. Temperature Range: up to 2000F. Tensile Strength: 700 PSI. Waterproof formula, can be machined or sanded as needed once fully cured.