J-B Weld ExtremeHeat Paste is formulated to allow for repairs to iron, steel and metal in high temperature environments (1000 degrees F / 538 degrees C). When fully cured, this metallic compound can be drilled, machined or sanded. It is great for repairing cracks, small gaps, seam connections or holes in exhaust manifolds, pipe connections, mufflers, catalytic converters, outdoor grills, fire boxes, gas and commercial furnaces and water heaters.