Strange rust... on STAINLESS STEEL?

[MAURICE]

Got this a lot when I worked in the knife industry.

You have to care for anything steel. It will rust.
I have had several arguments with a friend who believes stainless absolutely will NOT rust.

Dont want rust? Talonite, Stellite. Neither make good gun parts.

 

[johnny blaze]

I have seen alot of stainless pistols and rifles. The only ones I have ever seen with rust are Rugers. Two Ruger autos and one Ruger rifle.
This is not a Ruger bashing comment, just that those are the only stainless guns that I have seen with rust on them.

 

[Zach S]

Howard C, I've never seen rust on 304 stainless. I'm not saying it cant happen, but I havent seen it. Since I can buy scrap material from work (where we fabricate sheetmetal parts), and I'm a car guy, I've used a good bit of it for misc brackets, exhaust hangers, ect. We havent had any 316 at work since, well, I cant remember. It may have been eliminated before I started at the company six years ago. I have seen some 430 stainless (magnetic) rust though... The scrap 430 is also put in the carbon steel dumpster, at the request of the scrapyard.

I have a stainless Para Companion that will rust in a few days of being carried. Not even a week. Its currently in a ziplock bag in the bottom of the safe untill I can remember to have it hardcromed. My stainless Colt 1991A1 would rust, however not so fast. Oiling it once a week would keep the rust away. My stainless Kimbers hold up very well.

 

[mrmeval]

It could be some imperfection in the steel or it could have been steel left on or imbedded in the stainless from machining. Passivating stainless is done to prevent that and force a thicker protective layer on it.

 

[vesmcd]

As posted above, there are different grades of "stainless" steel. I have had stainless firearms(and knives) that wouldn't rust even if you dipped them in the ocean and sealed them in a plastic bag. On the othe end of the spectrum, I had an AMT .380 Backup that turned orange the first time I carried it in my pants pocket on a hot day.

 

[HowardC]

Zach:

I see your point. I guess maybe it's not really a 'rust', but a brown coating that it seems to weather to. We have heat exchangers labeled '304', and sometimes scratches in the surface will get a rust like coating in it. No, it doesn't form a real oxide layer with much depth. And, certainly not like a carbon steel. And, there are grades of 304 and 316, obviously.
We had a tank (~100 gal) that was outside for maybe 20 yrs. It had a brown coating, but you could scratch or sand through the colored layer in a few thousandths or so. I admit, I don't know exactly what kind of SS it was. It contained NO2. I'm far from a metallurgist, so I'm just noting things I've seen.
But, back to the topic, clean and oil your stainless firearm frequently, especially if you carry it, and/or live in a humid climate.

Take care, -Howard