Strange rust... on STAINLESS STEEL?

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Hemicuda

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I have a Ruger 10/22 International in STAINLESS STEEL, and SOMEHOW it got some rust-blooms (honest to god redish RUST! they actually started to "pit" too) on the barrel (and some weird discolorations on the aluminum alloy action, ALL on the right (bolt handle) side...

The guns stored either side of it did NOT rust... (they are both blued guns...)

I ended up using a rag-wheel on a grinder motor and jewellers rouge on it to "fix" it... The end result is a mirror polished barrel and action, in a factory Ruger International setup... (the stock is even "tiger striped"...) this thing looks AWESOME...

Of course, I no longer have an original International either... (bit of a bummer)

My question is, HOW did my "stainless" Ruger end up rusting?
 
My question is, HOW did my "stainless" Ruger end up rusting?
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Because stainless is still steel, and steel can rust. Try leaving a piece of stainless in a glass of salt water for a few weeks and see what happens. Speaking personally, I have hands of evil and can rust any sort of steel practically before your eyes.
 
I would guess this

has something to do with an imperfect alloy mix. Stainless steel is steel with a nickel or whatever alloy, I don't know, mixed in it. They would have to be molten to be mixed like cake batter. I would guess that a small area had a bit too much steel and not enough alloy at that spot. I am NOT a scientist or engineer or metallurgist...just a guess.
 
Have you oiled it? Stainless is only rust resistant, not rust proof. Another possibility is that someone may have used steel wool to polish it at some time. The steel wool could embed steel splinters in the pores of the stainless steel and that is what starts the rust problem. On stainless guns use stainless steel wool or better yet copper wool if you can find it. These are only two possibilities and the real problem may be something else but these will get you started. Hope this helps.
When I was in private security I had many Officers bring their guns to me to clean for them because their stainless steel guns had mild to moderate rust. They were surprised it happened. One Sergeant in particular thought that her revolver was so rust proofed that she never wiped it down and oiled it when she worked in the rain. It looked worse than it was considering she had not cleaned it in six months.
Good luck.
 
Stainless steel doesn't rust as easily as blued, and doesn't wear off as easily as blued. It's steel, all the same. If it was nickel, that could be another situation entirely...
 
Actually, like aluminum, there are a wide variety of stainless steel alloys. As you've found out some are much more rust resistant than others. I believe there ARE some that are so rust resistant as to be effectively rust-proof---But, they may have other less desireable qualities like brittleness, or poor machinability.
 
If I remember right about 20 years ago "they" changed the standards for stainless to allow cheaper imports / cheaper products made here into the market. IMHO they went too far.
 
To remove the rust try Eezox and a pencil eraser. Then store after an Eezox rubdown. Sounds stupid I know...but it works.
 
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Something I learned the hard way, with knives, is that not all stainless steels are created equal. Each steel has it's own metullergy. Some, such as those from China, will tend to have low Chromium (IIRC), and will rust easier and have a general greater tendency to wear due to other cheapening propperties. Leatherman also uses a higher carbon to chromium ratio to effect a more durable better edge holding tool. Others, use different alloys, to increase rust reisistence. Needless to say, given the right conditions all will ultimately rust- the question is how fast? How easily?
 
My turbo miata has a stainless downpipe and exhaust. All the same grade and composition of steel. If you look at the far end of the exhaust (which is relatively cool), the steel is still shiny despite being exposed to years of water and road dirt. If you go up next to the turbine outlet which sees 1600 degree temperatures, the whole pipe is a sort of coppery golden brown, tapering to shiny steel color about 2 feet down.

Even stainless steel will discolor and rust eventually. Not as quickly as carbon steel, but it will happen.
 
The discoloration on the exhaust pipe is not rust. It is due to the high temperature. Take a look at motorcycle pipes that have been chromed - they discolor as soon as they see high temperatures - and the color varies with the temp.

Was the receiver of this rifle anodized? It was stated that there was rust discoloration on both barrel and receiver - I thought the 10/22 receiver was anodized aluminum - that will not rust.

After the rifle is cleaned, use some automotive paste wax to coat the metal - it will help keep the moisturwe away from the parts that can rust.
 
Actually, like aluminum, there are a wide variety of stainless steel alloys. As you've found out some are much more rust resistant than others. I believe there ARE some that are so rust resistant as to be effectively rust-proof---But, they may have other less desireable qualities like brittleness, or poor machinability.
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This is exactly correct. The nearly rustproof stainless steels are too brittle, and too difficult to machine for use in guns.

The chromium in stainless steel will form a non-permeable oxide layer on the surface of the steel. Once the chromium "rusts" it seals off the surface from further oxidation - exactly like aluminum. Aluminum is very reactive, but when exposed to oxygen it immediately forms a very thin oxide layer that is impermeable, and protects it from further oxidation.

If you immerse a piece of the super-rustproof stainless steel in water, salt water, many acids, etc. it will never rust. But, immerse it in a weak acid, and then scratch the surface with a glass rod, and you'll see bubbles - the glass rod scratched off the chromium oxide layer and allowed the acid to start eating away the metal inside. Because it was submersed and not exposed to oxygen, it couldn't form the protective layer

Some peoples skin oils can cause spots where the surface is not exposed to oxygen. If, while that is sealed off from the oxygen, something manages to scratch the oxide off the surface while not breaking the skin oil (ie. scratches the oxide but doesn't expose the metal underneath to the air) then the salts in the skin oil will start to rust the metal.

I hope that makes sense.
 
A stainless steel pistol was accidentally stored with blood on it. The blood spots caused deep pits in the steel, too deep to polish out. Rest of the gun was perfect.
 
You just got a visit from the rust fairy.

If you leave that gun under your pillow overnight, you'll find a quarter there in the morning. Sure, you've lost your gun, but hey... shiny new quarter, you know?
 
On Stainless Steels....

It has been my experience in the chemical industry, that you have to get into the high chrome/nickel stainless to be free of rust. eg: 304 SS will surface rust, darken, etc., especially at scratches, dings. 316 SS is pretty rust free and more corrosion resistant. None will stand up to aqueous solutions of the mineral acids. You have to get into the Hastalloy and Monel alloys to withstand strong acids, and the cost goes up exponentially. And, machinists I've dealt with dislike working with 316 as it is hard on tools, and difficult to machine cleanly.
From what I've gleaned, lots of gun SS is of the 410, 416 variety, which are less rust/stain resistant, but have much better machining properties. Even body sweat, etc can cause corrosion on stainless guns, I recently found some under the grips on my Springfield. Guess I"ll clean and oil it more often.

Interestingly enough, I recovered a stainless Model 64 Smith which sat in a police locker for 6-8 mo, with significant blood spots on it, and it cleaned up well, no pits, etc. Wonder what SS S/W uses?
Take care, HowardC
 
One of many,

please explain to the class what chemical process takes place in metal at high temperatures while exposed to the open atmosphere.

At elevated temperature, the metal comprising the stainless steel will combine with oxygen to form an oxide layer on the metal surface. The color of the "stain" is a function of the layer thickness. Oxidation of stainless steel indicates that the metal temperature at the oxidized surface was in excess of 1000F.
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Stainless doesnt rust away like iron because the oxide on the stainless steel stays attached and acts a barrier. Iron oxide flakes away from the unoxidized iron beneath and leads to erosion.
 
Umm..."(and some weird discolorations on the aluminum alloy action" - I DID NOT say "rust" on the action... I SAID weird discolorations... lol I ALSO said "Aluminum Alloy Action"...

NOW it's all mirror finished...
 
Reminds me of my Mini-14 (196- stainless ranch series) picked up a soft case for it and it got little wet from the car to the door. Just the same I let it dry a few hours and placed the mini in it's new home. The following morning I took it out for a look (had nothing better to do) and there was light surface rust. My reason for buying it was for it's stainless properties (got spoiled on my S&W 1076) in the first place. I was just suprised it showed corrosion in less than 12 hours and good thing I had nothing better to do that day. I suppose it's all bout the bottom line with the makers.
 
it depends on the grade of Stainless steel. 304L stainless with stand up to seawater. but is to soft for firearms. Most SST in firearms are 400 series, like 416. Some manufactures are now using 17-4 steel. 300 series will not take a magnet, 400 series and 17-4 will. 304 and 316 does not work well in firearms, but 410 and 416 and 17-4 works well because they have a higher carbon content and can be hardened some what by heat treating.
I have been machining SST for over 20 years. 316 SST is aggravating to machine, we cut it every day. Try Haynes 188 if you want something mean to machine
 
I'm a boat dealer and we get this same question every spring.
Yes stainless is stainless...it is not stain proof.
Rustless, but not rust proof.
As has been explained, totally stain proof steel wouldn't be the correct hardness for the job at hand.

I have guys all upset because they can stick a magnet to a stainless steel prop. They figure they got ripped off, until they do a little more research....
 
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