409 is NOT for nice cars exhaust systems.... as it forms a light layer of rust. That's not the kind of stainless exhaust "we" are looking for.
321 does NOT polish well.... but otherwise works well for our purposes. I'll add that it is better for higher heat applications than normal 304
The food grade stainless in my '32 exhaust is polished to a mirror grade -- but the growth/shrinkage rate is really unacceptable in an exhaust system other
than a "show" car. The food grade tubing works great for bends - since the diameter matches up no matter where you cut it. In other words - you can buy a 90 or 180 and cut it and match it to another cut curved piece and the diameters match up. Nice in a show car exhaust system -- really not very critical in an under car
"used/abused" PT car.
Last edited by GregWeld; 01-02-2013 at 11:52 AM.
Reason: added info
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