Which copper sealant for exhaust gaskets?

[Oro_O]

I have to re-install an exhaust system from the manifold back in a few days. Locally I can get

1) Permatex ultra copper, squeeze tube

http://www.permatex.com/products-2/produ...et-maker-detail


2) K&W (CRC) Copper coat:

http://crcindustries.com/auto/?s=401504

It says the working temp of the Permatex is 700F, that of the K&W 400F. Is that adequate? I'd rather get the K&W as it's got a dauber for easier/more precise application than the Permatex tube.

Sound ok or go with the permatex? I notice the K&W doesn't specifically mention exhausts in its application recommendations.

 

[Merkava_4]

Who told you you have to use gasket sealant on exhaust gaskets ?

Usually exhaust gaskets have that silver coating (whatever it is) that protects the gaskets from heat.

 

[Trav]

You don't need any. Using a sealer in these areas can actually cause leaks when the sealer eventually fails.

 

[Merkava_4]

Hey Trav -- what's that stuff they put on exhaust manifold gaskets that looks like chrome ?

 

[SteveSRT8]

Most gaskets for exhaust are ready to use. A clean surface is all they need. The gasket mfgr should tell you what to do...

 

[The_Eric]

The only sealant I've ever used (and that's usually only for problem areas or when putting a manifold direct to the cyl head) is Taber's Flo-Ex. It's a little mom and pop company out of Missouri and it strait up works.

They call it a hot gasket cement. Goes on runny and hardens/expands with heat.

 

[Merkava_4]

This is what I'm talking about here. The shiny silver stuff. What is it ?

 

[Bluestream]

Likely a Zinc coating..What difference does it make what it is?

no sealant is needed as others said..

tHIS IS HIGH TEMP rtv

http://www.permatex.com/products-2/produ...e-gasket-detail

 

[Merkava_4]

Originally Posted By: Bluestream
What difference does it make what it is?


I'm impressed by that stuff. I've got as whole stack of Briggs & Stratton head gaskets made out of that stuff and I've reused them several times. The gaskets never wear out like carburetor gaskets do.

 

[mk378]

The silver color is graphite (a form of elemental carbon). The whole gasket is made of solid graphite. It is not a coating.

 

[Trav]

Originally Posted By: Merkava_4
This is what I'm talking about here. The shiny silver stuff. What is it ?

Thin aluminum sheet over graphite AFAIK.

 

[Merkava_4]

Originally Posted By: Trav
Thin aluminum sheet over graphite AFAIK.


Thank you sir. That makes perfect sense. And if I had to guess, I'd say the perforations in the thin layer of aluminum is to help it compress.

 

[Trav]

I would guess it helps keep the substrate material together also.

 

[SteveSRT8]

Originally Posted By: Trav
I would guess it helps keep the substrate material together also.


Indeed, I am pretty sure there are zero gaskets made of pure graphite!