J-B Weld ExtremeHeat Putty is formulated to allow for repairs to iron, steel and metal in high temperature environments (1000F / 538C). 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. This product is water based, non-flammable and contains no solvents or Volatile Organic Compounds (VOCs). Great for: exhaust manifolds, heat exchangers, mufflers, outdoor grills & fireplaces.  Specifications: Temperature Limit: 538C.Setting Time: 1 Hour.Cure Time: 24 Hours.Colour When Dry: Machine Grey.Size: 85g.