Stainless exhaust 304 or 409?

[CumminsBu]

I have seen some 409 stainless nuts and bolts rust. Does anyone with 409 exhaust have rust on them? I was looking to get the MBRP COOL DUELS ethier 409 or 304. Which one is better?

BP

 

[Blakers]

The 304 stainless is food grade and will not rust. I think the 400 series stainless has more of a chrome-like shine, but actually has carbon steel in the middle and will eventually rust.



Blake

 

[JHardwick]

The 304 stainless is food grade and will not rust. I think the 400 series stainless has more of a chrome-like shine, but actually has carbon steel in the middle and will eventually rust.



Blake

It doesn't actually have "carbon steel in the middle", but 400 series does have a higher carbon content. Some 400 series stainless is even heat treatable for hardening.

 

[COSEng]

304 is going to be more corrosion resistant (no rust) as

stated above. 409 is more resistant to acid erosion. 409 is

cheaper and is what is used on most OEM stainless systems.

It will "rust". 304 will "look" better longer.



I would get the 304 if the budget allows.



Carl

 

[Blakers]

It doesn't actually have "carbon steel in the middle", but 400 series does have a higher carbon content. Some 400 series stainless is even heat treatable for hardening.

Are you sure it is not laminated or electroplated somehow? I know some syrup pans are made from 430 and if you scratch it and expose the center, it will rust.

 

[bmoeller]

Some of the stainless will rust, once it has been heated enough (welding on it). I think even the 304 will. The heat seems to change it some how.

 

[JHardwick]

Are you sure it is not laminated or electroplated somehow? I know some syrup pans are made from 430 and if you scratch it and expose the center, it will rust.

A syrup pan may very well have a plating of some sort with a carbon steel base.