81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube

Working well on some ducting coming into and off of my furnace

good 😊

If you're working on anything high-heat, like an exhaust manifold or turbo application, this is the only gasket maker to use. The Ultra Copper RTV is a workhorse—it handles maximum temperatures without breaking down, shrinking, or leaking. It goes on smoothly, cures quickly, and forms a super durable, tight seal. I've used it on headers where standard RTV would just burn up, and this holds strong. It's the professional choice for reliability under extreme heat. Essential for engine work.

Works well. Good seal .

Used this for a couple projects and it works great. The silicone has amazing adhesive-ness and temperature resistance that even after hours of continuous heat its not budging. That being said, the bottle it comes in has a weak back stich. A little too much pressure on trying to push out stuff and all of the bottle exploded out the back end. product is great, packaging is unfortantely poor.

Use on exhaust or anyplace else you need a seal for extended high heat use!

The compond was fresh and worked like a champ. Didn't appear to be NOS. (New Old Stock). Will buy again when needed. Used it to reseal a used head gasket on an air compressor. Where and when I grew up, you are NOT supposed to reuse a used gasket. But mine was no longer available so had to reuse, it and Permatex worked fine.

Same product you buy at auto parts store but at a much better price