J-B Weld (PRO Size) is the original cold weld two-part epoxy system that provides strong, lasting repairs to metal and multiple surfaces. Mixed at a ratio of 1:1, it forms a permanent bond and can be shaped, tapped, filed, sanded and drilled after curing. At room temperature, j-b weld sets in 4-6 hours to a dark grey color. A full cure is reached in 15-24 hours. J-b weld has a tensile strength of 3960 lbs. per square inch and sets to a hard bond overnight. It can withstand temperatures up to 550 degree Fahrenheit when fully cured.