I will second this 100%... as the food grade SS exhaust on my Steve Frisbee built '32 Ford... has had to be repaired now for the second time. They (SAR) flushed the welds and polished the entire system... I drive the crap out of my stuff... and the system has/had hairline cracks at every seam. The SS also GROWS a BUNCH... and this has caused other issues.

I will nurse this thru this summer and then the car goes to Brizio for an all new exhaust system. :thumbsup: You know - one that actually works.:D

try triggering the weld just doing one tack after another not doing it solid turn your heat down and purge it with any inert gas it will work just practice a bit more it is possible just not the best way but it does work. good luck with any way you choose.myself would use mild steel and send it out to get it ceramic coated after looks better and stays that way.:D

All said and done I agree. Stainless has too many drawbacks for my application.

I agree... even Brizio said they stopped doing stainless exhaust systems...



If you're going to do SS exhaust -- use 321 stainless from a supplier like Burns Stainless.

I guess I am the odd man out. I like stainless exhaust. If built properly it will last the life of the car, it is easier to maintain than a coated exhaust, and actually does a better job of retaining heat than mild steel.

Like most things Donny -- you've got to use the correct materials for the job.

Most failures on stainless exhaust come from improper mounting of the exhaust. Since the stainless grows then shrinks a ton using multiple expansion couplers, and making sure the rest of the mounts can move on the car is paramount.

I always laugh when I tell a customer that his side exhaust tip is going to stick out up to an 1" from where it is cold, and that it will return. The response is "really I've never seen that before, my buddies doesn't do that." LOL Well then your "buddies" isn't stainless...

Im wondering if the wrong grade stainless was used. It seams that most over-the counter stainless is the 304 grade.

Anybody use the 321, 347 or the specific 409 grade for exhaust.

I was just looking at the stainless grade chart and the 321,347 is a stabilised grade for heavy section welding and high temperatures.

Then I saw that the stainless grade 409 is listed as automotive exhaust grade that is weld stabilised.

I was thinking of building a light weight stainless exhaust similar to an airplane, but now I maybe second quesing that idea based on what Im seeing here.

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.

Most failures on stainless exhaust come from improper mounting of the exhaust. Since the stainless grows then shrinks a ton using multiple expansion couplers, and making sure the rest of the mounts can move on the car is paramount.

Very nicely put :thumbsup: I'm making mine all 304 SS ( headers to the tailpipe) don't want corrosion holes down the line among its other benefits.

That is my struggle, giving it room to expand while keeping it tight to the body.