Extending life of mild steel exhuast?

[shortlid]

I was talking to a guy at one of the trusty online part houses. He stated to me that spraying my exhuast system down with high temp Silicone would keep it from rusting out from the exterior so fast? True or False, I have never heard of this, trick??:-\ Coulc help us with the stock mild steel exhuast that Subaru still fails to upgrade to SS.

[Andyjo]

if you have a stock subi exhaust, it should be galvinized (zinc plated) and not rust THAT bad... unless you're like make and like to remove the plating w/ rocks, small trees, DEEP mud at high velocity... etc...

[Setright]

Sound like anyone you know Andy??

 

 

I would stick to spray painting with a high temp paint. Degrease the pipes first, apply a very thing coat and let that dry fully before applying the second and third coats. Concentrate on covering the welds, they are the weak link in terms of rust.

[OB99W]

I was talking to a guy at one of the trusty online part houses. He stated to me that spraying my exhuast system down with high temp Silicone would keep it from rusting out from the exterior so fast? [...]

It probably would reduce exterior rust. However, it's unlikely to make much of a difference in exhaust system life, since most of the rusting occurs from the inside out, due to the corrosive nature of exhaust gases. If you do protect the exterior, don't let appearance provide a false sense of security. It's a good idea every so often to tap on the pipes, etc., to see if things still seem solid (or collapse ).

[shortlid]

Most of the systems I have had fail are not from baffles blowing out, but rustng and cracking at welds.

[ferret]

True statement about the welds. On EVERY vehicle we have owned since 1980 (Saab 900T at that time), The welds were the point of failure !! Other than an accident damaging the exhaust, the mufflers and pipes have survived well, but the welds especially by the flange or spring loaded movable joints were our weak points.

End of my $.02

[OB99W]

Most of the systems I have had fail are not from baffles blowing out, but rustng and cracking at welds.

That's not surprising. The parts are typically aluminized or galvanized. Welding vaporizes or otherwise removes that plating, which typically isn't particularly thick anyway. Not only that, but the temper of the metal is changed by the heat, and the weld material obviously doesn't have the flexibility/ductility of the pieces being joined. Some welding fluxes are themselves corrosive.

 

If you could clean the weld area and coat it with an anti-corrosive from the inside, that might make enough difference to be significant. Unfortunately, the welded joints often can't be reached after assembly.