Which Sealant To Use For Muffler?

[aircobra]

the story is that i have a NOS exhaust pipe, but have had to get an aftermarket muffler. the size doesn't quite match but about 3mms.

the bloke at truefit expanded the pipe with one of these hydraulic jaws. he then and  said to use the permatex high temp grey silicone,

but either this one

http://www.supercheapauto.com.au/Product/CRC-Maniseal-Exhaust-Cement-Brown-145g/1449

http://www.supercheapauto.com.au/Product/Permatex-Ultra-Copper-RTV-Silicone-Gasket-Maker-Maximum-Temperature-85g/114976

anyone used any of them?

the joint is going to be secured by a standard u-clamp. i'm thinking that the silcone based paste will a bit more flexible, whereas the other paste dries rock hard and may crumble

[rb25240z]

Definitely go option 2 the copper silicon. I have used this to seal up a leaking waste gate flange and it has lasted years. Should easily handle being used at the muffler. 

[HKSZ]

My exhuast man uses Red so do I and yes avoid paste / cement type sealants for the reasons u mentioned

[PB260Z]

Hi

 

I use the Permatex Ultra Copper in any joins that have any movement.

But in straight muffler to pipe connections I use the cement.

 

Both work very, but the cement will not copy with movement.

 

Cheers

 

PB

[aircobra]

went to repco and the locite version is twice the price for the same specs!!!

http://www.loctite.com.au/3320_AUE_HTML.htm?nodeid=8802627420161&msdsLanguage=EN_AU&selectedTab=technical

http://www.supercheapauto.com.au/Product/Permatex-Ultra-Copper-RTV-Silicone-Gasket-Maker-Maximum-Temperature-85g/114976