Have been told that stainless systems tend not to last more than a few years due to vibration damage (from being rigid) when fitted to a veedub. But love the idea of a stainless system to avoid rust.

Any opinions to share on this?

Can ceramic coating be applied to mild steel?
If so that may be a good option for looks and rust.

There's some cheap stainless systems out there on the market, probably best to avoid those for all the reasons you mentioned and more. You get what you pay for.

I've got both at the moment and still always like the sound of mild steel, but don't last like the stainless

>"Can ceramic coating be applied to mild steel?"<

Yes, I've had a couple of Lukey mufflers ceramic coated - they beed blast first, which looks like a matt grey finish and then clear ceramic bake them.
The final finish looks more like a polished aluminium colour than a chrome finish. Make sure that you do all reshaping or welding before the coating.
Also, when clamping the new ceramic coating, I used that muffler putty as a sealer before tightening. I'm told that the hottest range of silicon gasket is good??

I also prefer the sound of mild steel over stainless - in the good old days, copper pipes sounded at least 10 mph faster.

These A1 systems look the goods

http://airkewld.com/index.php?page=shop.product_details&flypage=ilvm_fly_...

Copper looks and sounds awesome! But is illegal now as it emits some gas from the copper when used for exhaust.

Pity

I believe the main reason some mild steel exhausts rust away fast is that they are made from very poor quality metal..

and some stainless steel is very thin, and there are many different stainless steels too..

so,it all comes down to the quality of the metal..

I remember reading many years ago of a fellow putting a grease nipple in the exhaust and greasing the exhaust every few months to stop the GOLF muffler from rusting away from the inside.. this wouldn't be good for a catalytic converter.. lol

cheers

LEE

I wonder whether using heat proof paints like the pot belly black etc inside the pipes would help? Or have the whole thing plated in something that will keep the corrosion down to a minimum.

The guy I spoke to about it told me that a lot of folk who bought stainless a few years back are starting to find they are cracking just from stress and vibration. Probably nopt an issue on a regular exhaust system since the parts are supported on flexible rubber hangers so not rigid like a VW one. He reckons that the mild steel is the way to go.

I have had NO probs with stainless systems and have been running them for the last 10 years.

So under normal daily usage, how long should one expect a standard set of mild steel exhausts to last? I remember on Dad's 2 litre kombi the exhaust having to be replaced several times in the 10 years or so we had the car. On the other hand I've seldom if ever had to replace an exhaust on any other vehicle except when damaged by something, never had one rust out except on vee dubs.

Is there any logical reason why this would be the case?

Your dad bought cheap exhausts.

maybe people should think of using an exhaust hanger on their fatboy 4-1 mufflers?

I did when my old mild steel one cracked around the muffler pipe entrance. After using the hanger the cheap quiet pack muffler lasted until the baffles went many years later

"stainless" mufflers are generally 409 grade, there is JUST enough chromium & stuff in it to barely be classed as stainless & it will rust soon after mild steel, just like repro chrome parts do. Be specific & ask for proof that it's full 304/316 grade, will last forever. I may have it back to front but 304 is industrial & 316 is medical, should know, work with the stuff often enough
Or if you're handy with the welding gear, try making your own! No seriously don't, it's painfully time consuming

Was talking to a Engineer at work who makes drum rollers for conveyors and he said, exhaust 316 can be very thin shit. My VS on the kombi is about 12 months old and seems to be hanging in there. Just not real happy on how its staining.

Guy's, stainless discolours....nothing new, and it is an exhaust system, even hi-temp paint is high in maintenance. If you want show quality for a vehicle that gets used, your best ceramic coating a stainless system. They run quieter, cooler (externally) and last (probably) indefinately, but still to stay pretty, they need cleaning regularly.

My last stainless set up discolour'd but not the way my VS has. I like it when stainless gets the heat staining but not the way mine has gone. VS does tuck nice and is a really good set up for the lowered.
I'm putting a mild steel on the split next (Monza gone) week was thinking about Ceramic coating it but might look a bit to flash for Ratso.

You can get ceramic in black or even cast iron look grey.......Ring Custom Coatings, Archerfield. Best around, they will do majority of internals too depending on the system.

Black sounds good...might give them a buzz

Quote:

Originally posted by STIDUB "stainless" mufflers are generally 409 grade, there is JUST enough chromium & stuff in it to barely be classed as stainless & it will rust soon after mild steel, just like repro chrome parts do. Be specific & ask for proof that it's full 304/316 grade, will last forever. I may have it back to front but 304 is industrial & 316 is medical, should know, work with the stuff often enough Or if you're handy with the welding gear, try making your own! No seriously don't, it's painfully time consuming

Some people pay extra for the burnt look!
Pipe should be 1.6mm thick regardless of grade
And yes 409 is cheap(er) crap, can't say I've ever come across any locally

Ps if making your own pipes, midway metals at yatala or bestmuffler online seem to be best prices

A Mate of mine who works for BP reckons fuels nowadays are a lot less corrosive, so probably mild steel is a good option (having said that I have recently bought a VS SS exhaust from Matt however if the VS design had been available in mild steel, I would have been happy with that) I am currently running a mild steel 4 into 1 that I bought years ago second hand and it is still ok.I do remember that copper does sound really good though.
Cheers.........Wayne

Yeah..... i'm not sure the 409 is the crap stuff either. might have got your wires crossed there STIDUB.
I do agree that the expansion rate of the stainless is the killer (that and cheap material) I'm building a stainless system for the baja because i'm sick of them rusting away on me all the time and will be putting one of those flexible joints between the 2 halves of the system.

When 304 and 316 grade stainless steels are held at elevated temperatures for long periods (say 500C for 100 hrs or so), the crystalline structure can change to a form referred to as "martensitic". This structure is much more brittle than the original and can lead to cracking failures which are sometimes experienced in e.g. oil refinery column trays which operate under exactly these conditions.

If a 304/316 stainless exhaust is of adequate thickness and properly supported, it would be unlikely to experience such a failure in a reasonable exhaust lifetime; however, some systems are made of very light materials and (especially on air-cooled VWs) are poorly supported. In such circumstances, martensitic embrittlement failures would be expected.

I have no experience testing 409 grade SS, so I don't know how that grade would react to long-term elevated temperatures. No direct equivalent embrittlement process exists for mild carbon steeels, though as noted by other posters it is prone to rusting, which will determine the effective lifetime of a carbon steel exhaust earlier than anything else.

A decent quality stainless or carbon steel system will give an acceptable lifetime if properly supported, and *that* is the big issue with air-cooled VWs, of far more importance than the choice between SS and CS.

hth