Opinions on best exhaust joint cement

Post by **JimBee** » 31 May 2022, 19:13

I'm piecing together an exhaust pipe link. Joints (there will be 4) will be clamped when it's finally set up. I'd like to seal them as the pieces are fit together. I think I recall some debate about the best cement to use, but I don't remember what it was—or if most people agreed on it

Suggestions appreciated!

Jim

Post by **abscate** » 31 May 2022, 20:46

Permatex makes some nice stuff for slip joints. If the hole is larger, then JB Weld extreme heat epoxy

Post by **Sveedy** » 01 Jun 2022, 08:47

Personally I'd be worried about being able to separate the joints in the future if you put sealant pukkie in there during assembly.
Maybe a bit on the outside of the flange once everything is tightened down, but most "good" exhaust clamps will do the job on their own.
Just might have to retighten them after a few hot / cold cycles.

Post by **JimBee** » 05 Jun 2022, 11:15

Thanks, gentlemen of the wrench for the info. Onward and upward!

Post by **FireFox31** » 05 Jun 2022, 22:50

I fought with my clamped and cemented exhaust for years. It always leaked and the clamps would rust out. The best solution I found is to have the parts welded together by a muffler shop. They'll spray the welds with rust inhibitor to make them last longer. No, you can't easily take it apart again. But, the time savings and long term trouble free operation justifies all the costs.

Post by **abscate** » 06 Jun 2022, 03:56

Stainless steel (304) band clamps and permeatex work great. The Starla mufflers last 3-5 years, after which a sledge hammer reduces then to return shippable size to FReeCP , courtesy of my NJ Counselor.

Post by **JimBee** » 07 Jun 2022, 13:51

Searching on JB Weld I found this video: guy repairs a cracked BMW block with JB Weld (marine version). Looks like he drilled a hole (2 mm) at either end of the crack to limit further spreading. Repair looks neat. Will it last?
https://www.google.com/search?client=fi ... QPv5Gz4AU4

Post by **BlackBart** » 07 Jun 2022, 14:00

What exactly is JB Weld? Is it epoxy? How does it bond with oil-imbedded aluminum or cast iron?

Post by **Goupil** » 08 Jun 2022, 14:13

It's epoxy with metal particles in it if I remember correctly. I've not managed to find an equivalent of JB Weld on this side of the Atlantic, but I see americans praising it quite often

Post by **scot850** » 08 Jun 2022, 14:41

JB Weld has many versions and applications from heat resistant, water proof, plastic and more. I love the stuff. Drilling a small hole either end of the crack is key to stopping the weld propagating. By having the round hole there is no point weaker than the other around the circumference. Had this done on a windshield to stop the crack elongating. Crack was just the same 5 years later!

Neil