how to tell stainless exhaust?

Post by **CRUSHU** » Wed May 21, 2008 10:54 pm

I have some new OEM extractors, and want to know if they are stainless or not. They look shiney, but so does new mild steel exhaust.
any tips?

Post by **Troopy93** » Wed May 21, 2008 11:09 pm

Stick a magnet on them if it drops off they're stainless

Post by **Troopy93** » Wed May 21, 2008 11:10 pm

Stick a magnet on them if it drops off they're stainless

Post by **awill4x4** » Wed May 21, 2008 11:38 pm

Troopy93 wrote:Stick a magnet on them if it drops off they're stainless

Yes, if it drops off it is stainless but it could still be a magnetic grade (Ferritic) of stainless (grade 409 comes to mind)
Regards Andrew.

Post by **Tom0** » Thu May 22, 2008 6:52 am

Scrub them clean with soapy water to remove grease, then spray lightly with supersaturated salt water solution... wait 1 day. When they're all rusty, you'll know.

Post by **Ruffy** » Thu May 22, 2008 7:33 am

Try and scratch them.

Post by **Troopy93** » Thu May 22, 2008 7:50 am

awill4x4 wrote:
Troopy93 wrote:Stick a magnet on them if it drops off they're stainless
Yes, if it drops off it is stainless but it could still be a magnetic grade (Ferritic) of stainless (grade 409 comes to mind)
Regards Andrew.

Yeah true, but most system wouls likely be made out of 309 or 316 if they were to last. Just have the problem then of cracking down the track after work hardening.

Post by **RO8M** » Thu May 22, 2008 10:07 am

Ruffy wrote:Try and scratch them.

... and ... ?

Post by **chimpboy** » Thu May 22, 2008 10:23 am

Apparently you can tell by applying a copper sulphate solution to a section of the metal. I have never tried it. The (blue) cuso4 solution turns coppery red on non-stainless, but nothing happens on stainless.

But... there are a couple of grades of stainless that give a false result.

There is another test using ferroxyl.

I've never used either of these but you might be able to find out more if you look them up.

Post by **Struth** » Thu May 22, 2008 4:30 pm

The easiest method is to scratch one with a stainless steel ruler.

Then wet it and have a look the next day.

If they are stainless a layer of chromium oxide will form and protect from rust (it will still be shiny).

If they are mild steel a layer or iron oxide will form (rust).

It,s that simple.

Even non ferritic stainless can become magnetic if deep drawn or work hardened.

Try the magnet trick on you laundry trough at the top corner where deep drawing has occured, the magnet is likely to stick

Cheers

Post by **mike_nofx** » Thu May 22, 2008 5:42 pm

the simplest method would be (as already posted) lightly rub back, then spray with water, with or without salt.
Surface rust will build up within 1 day. Ive seen surface rust appear on mild steel in an hour!

Post by **hilux79** » Thu May 22, 2008 5:48 pm

chimpboy wrote:Apparently you can tell by applying a copper sulphate solution to a section of the metal. I have never tried it. The (blue) cuso4 solution turns coppery red on non-stainless, but nothing happens on stainless.
.

Yes this is correct I have used this trick at work to check if protective plating's are still on certain fasteners.

Post by **Ruffy** » Thu May 22, 2008 6:55 pm

RO8M wrote:
Ruffy wrote:Try and scratch them.
... and ... ?

Mild steel is considerably softer and therefore easy to scratch.

Website · Post by **LuxyBoy** » Thu May 22, 2008 7:46 pm

What is the usual grade of stainless to make an exhaust system not rust on the beach

Do all grades suffer from work hardening and cracking

Post by **Struth** » Thu May 22, 2008 8:51 pm

LuxyBoy wrote:What is the usual grade of stainless to make an exhaust system not rust on the beach
Do all grades suffer from work hardening and cracking

316L for the beach, but 304 will do.

All steel work hardens and cracks, if you have loose bits that allow vibrations you will get work hardening and cracking.

Cheers

Post by **awill4x4** » Thu May 22, 2008 10:21 pm

Troopy93 wrote:
awill4x4 wrote:
Troopy93 wrote:Stick a magnet on them if it drops off they're stainless
Yes, if it drops off it is stainless but it could still be a magnetic grade (Ferritic) of stainless (grade 409 comes to mind)
Regards Andrew.
Yeah true, but most system wouls likely be made out of 309 or 316 if they were to last. Just have the problem then of cracking down the track after work hardening.

I'm sorry, but you're wrong. Most Stainless systems built by the major exhaust companies (pacemaker, HM, Lukey, DeFillipo etc) use 409 grade stainless which is an acceptable exhaust grade. HM Headers even give a 10 year warranty on them, with some exceptions of course.
Regards Andrew.

Website · Post by **LuxyBoy** » Fri May 23, 2008 7:35 am

So is it worth getting a stainless system made or just save the money and replace a mild steel or aluminised one more regularly

Post by **chimpboy** » Fri May 23, 2008 9:25 am

Mild steel exhausts sound better.

Post by **Gwagensteve** » Fri May 23, 2008 9:29 am

Copper and titanium sound grouse. they seem to get that lovely hollow "ringing" sound.

*back to topic*

Steve.

Post by **bru21** » Fri May 23, 2008 11:44 am

LuxyBoy wrote:So is it worth getting a stainless system made or just save the money and replace a mild steel or aluminised one more regularly

I made 316 headers on chevy smurf, they didn't crack while I had it.

ensure the whole lot is well attached to the motor / drive line and that all tubes will expand evenly - ie don't weld a 2" long tube to the middle of a 12" tube - they will grow by different amounts when the heat up / cool down.

my whole system cost $550 inc flanges all the tube and the 21/2 for the tail pipes. this was all 316 and heaps of bends. it was a diy project though and tey are a lot of work!

Post by **j-top paj** » Fri May 23, 2008 12:30 pm

so are they stainless?

Post by **Struth** » Fri May 23, 2008 2:34 pm

j-top paj wrote:so are they stainless?

Yes we have provided umpteen ways of checking, are they stainless?

Outer Limits 4x4 Board

how to tell stainless exhaust?

how to tell stainless exhaust?

Who is online