Ultra Copper Gasket Maker

The tube sat in my garage through a full winter before I finally needed it, and it still squeezed out smooth and spread evenly over the exhaust flange. Cured fast enough that I didn't have to babysit the job, and so far no leaks after a week of daily driving.

This stuff handled a cracked manifold flange on my work truck without any leaks. The high temp rating gave me confidence it would hold up. It's thick and doesn't run everywhere, which made application clean and easy.

I used this on a rusty exhaust slip-joint that had been leaking for months, and it held up perfectly even after a long highway drive. The tube was easy to apply, and the high-temp silicone cured faster than I expected.