Opinions on best exhaust joint cement

[Nevada1906]

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

It's a steel-impregnated epoxy resin. You can repair cracked engine blocks with it. You can even drill and tap it. It's the super glue of the car world.

The ambitious make entire engine blocks out of it.

[MrAl]

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

Hi,

On my old old Hyundai i used Permatex Ultra Copper silicone sealant. I think it is the highest temperature rated silicone or at least the highest temperature i could find back then.
I would cut an aluminum can top and bottom off, then cut up the side making a sleeve that opens. I then would coat the pipe with the silicone, then wrap the sleeve around the pipe over top of the silicone while it is still wet. Then two stainless steel hose clamps one at each end of the sleeve. Got me through inspection and it lasts for a decent amount of time.

JB Weld epoxy is pretty good i used that too in the engine compartment for some of the pollution control stuff.
This is not JB Kwik epoxy though, JB Kwik does not have as high of a temperature rating as the straight JB Weld epoxy.
Unfortunately JB Weld takes a lot longer to cure than JB Kwik but if you want the higher temp you have to go with the JB Weld.
The stuff, like most epoxies, is quite runny so it's hard to fill larger joints. In that case, get some heavy grade steel wool and saturate the wool with JB Weld as you wrap it around a pipe. The steel wool keeps if from running.

I've looked into the clay type exhaust system stuff and didnt like it.

The other thing to think about is mechanically it is better to wrap any pipe all the way around rather than just on a side, top or bottom. The wrap around acts like a sleeve that cant come off unless something really goes wrong.

Lastly, you should do a test first to make sure the stuff you buy actually cures. I had gotten some JB Weld off the web one time that did not actually harden enough. If you really want to make sure, test some on a pipe first too and run the car to see if it does not burn up.

Good luck with it,
AL

[3p141592654]

Permatex Optimum Red High Temperature Gasket maker will go to 750F. I have used it to seal leaking exhaust flanges that are not flat and it survives that environment.

[abscate]

You can buy band clamps now that perform the function of the cut can but have much better holding and clamping power than hose clamps, for about $10.

I gave up on the ball and sockets on my cat to muffler connections and just use these on my Volvos now, appropriately sized.


https://www.amazon.com/EVIL-ENERGY-Exha ... C59&sr=8-3

[MrAl]

You can buy band clamps now that perform the function of the cut can but have much better holding and clamping power than hose clamps, for about $10.

I gave up on the ball and sockets on my cat to muffler connections and just use these on my Volvos now, appropriately sized.


https://www.amazon.com/EVIL-ENERGY-Exha ... C59&sr=8-3

Look pretty nice. Wonder if they had them 10 to 20 years ago when had my old Hyundai.