On Jun 25, 2011, at 6:00 PM, David Beierl wrote:

> Bob, my impression is that's not  the case here in the salt belt.
Indeed, that's my "qualifier" in my follow up post. We get some of
that here. The 3 shops I deal with here (salt lake) who do exhaust
work exclusively, all say they find interior pipe rusting as the primary
cause of system failure. It's not so much a factor with newer aluminized
steel pipes which will corrode, but not nearly as fast as old mild steel.
b