Polishing Stainless; G3 compound on Exhaust

Cleaning my exhaust up, not just the tail pipe but the main unit. Polishing it at the moment just with various buffers and mops, basic polishes at the moment.

I've just concerns perhaps using a polish might remove the passive layer and cause issues with rust prevention. Haven't much experience in stainless steel polishing.

I don't want to use a metal polish, as it won't go far enough for the area I'm polishing.

Maybe you need to get out more often?

Ive used g3 compound on my exhaust before, it seems to work ok on the tail pipe, but it never made me go wow. Bodywork - different story. Will be interested to know as ive tried it on my polished wheels as well, just to see, and it didnt do too much lol

I would definitely be using a dedicated metal polish for a stainless exhaust. Some fine grade wire wool to remove any tar spots

Cleaning my exhaust up, not just the tail pipe but the main unit. Polishing it at the moment just with various buffers and mops, basic polishes at the moment.

 

I've just concerns perhaps using a polish might remove the passive layer and cause issues with rust prevention. Haven't much experience in stainless steel polishing.

 

I don't want to use a metal polish, as it won't go far enough for the area I'm polishing.

St/st doesn't rust and here's a bit of tech info I found

St St Corrosion Resistance

Corrosion

Corrosion can be defined as the attack of a metallic material by its environment. Stainless steels all possess a high resistance to corrosion. This resistance is conferred by the naturally occurring chromium - rich oxide film which is always present on the surface of stainless steel. Although less than 130 Angstrom thick (1 Angstrom unit = 10-8 cm) this invisible film is extremely protective as it is inert and adheres tightly to the metal. The oxide film has the unique property of self-repair which is unattainable in applied films. This means that if the film is removed or damaged or a new metal surface is created by cutting then in the atmosphere or other source of oxygen the protection will be instantaneously re-established. The more highly alloyed grades of stainless steel possess the best corrosion resistance and are able to withstand more aggressive environments.

Selection of the correct grade of stainless steel is the key to avoidance of corrosion problems.

In my previous job we used to passivated stainless steel.

If the layer is disturbed and not allow to be re created it will indeed begin to rust.

By using some chemicals it will react. And indeed corrode. Perhaps not through typical means.

Stainless steel can and will indeed corrode in a rust like fashion through introduction of some chemicals if not allowed to form it's passive layer with oxygen

Double post.

I'd personally use some very fine grade wire wool if the exhaust is showing her age along with a load of panel wipe. Then I'd probably go straight to some fine cut metal Polish and finish with something like the Meguires metal Polish. Then a few coats of poor boys sealant or a good wax.

In my previous job we used to passivated stainless steel.

 

If the layer is disturbed and not allow to be re created it will indeed begin to rust.

 

By using some chemicals it will react. And indeed corrode. Perhaps not through typical means.

 

Stainless steel can and will indeed corrode in a rust like fashion through introduction of some chemicals if not allowed to form it's passive layer with oxygen

Not all stainless steel is the same, look at cutlery, or spanners etc they get their surface disturbed with not rusting. It's graded, the stock supra exhausts are stainless but rust on the surface, lots of after market exhausts are the higher grade mirror polish able stuff.

Eg Grade 304 vs 316

I'm surprised no one has mentioned Autosol, I haven't used it for years but it used to be great stuff.

Not all stainless steel is the same, look at cutlery, or spanners etc they get their surface disturbed with not rusting. It's graded, the stock supra exhausts are stainless but rust on the surface, lots of after market exhausts are the higher grade mirror polish able stuff.

 

Eg Grade 304 vs 316

Yup. 304 is typically automotive industry grade. Like my exhaust. Sadly they didn't use the same grade for the welding

In oil and gas industry we use to work with 316 because it had better qualities as sea applications are seriously corrosive in comparison to most other uses.

My exhaust from VWR doesn't seem to polish up too well or even last too much time without becoming dull

Maybe have to search online for info on what they use exactly.

304 is a better grade to use for exhaust application in most cases as it's less inclined to crack due to contraction/expansion (316 physically will expand-contract more than 304 but being more ferrous will rust

Perfect compromise is 304 mani-down and mid, and 316 tail

Unfortunately some stainless exhausts have poor welds , I had to grind out my nur spec welds and tig them using decent rods