Stainless S&W: Passivation and Polishing

Am I correct in believing that polishing the revolver will remove the passivation process? How important is the passivation, anyway? I mean, it's still stainless right… does passivation really make that big of a difference?

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Howdy

Yes and no.

Passivation is an interesting subject. All ferrous metals; iron and steel, want to return to their natural state in nature. Pure iron does not exist in nature. It wants to combine with oxygen to form iron oxide, which we call rust, or corrosion. The way to prevent iron or normal alloy steels from corroding it to seal it off from atmospheric oxygen. Paint and oil can accomplish this. So can a thin, carefully controlled layer of iron oxide. That is what gun blue is, it is a very carefully applied form of rust. The base steel has been highly polished, and the bluing salts form a thin layer of blue (actually a form of oxide). This layer of oxide seals off the underlying base metal from atmospheric oxygen and prevents further corrosion.

Stainless Steel is a different story. First off, there are many, many different alloys of Stainless Steel, different alloys are formulated for different properties. In the steel industry they are usually referred to as Corrosion Resistant Steel, not Stainless. Notice it says Corrosion Resistant, not Corrosion Proof. Given the right conditions, most Stainless Steels will corrode.

Anyway, the definition of Stainless Steel is a steel with a minimum content of 10.5% Chromium. Chromium is the secret to the success of Stainless Steel. When the Stainless is molten, the Chromium is evenly distributed throughout the alloy. Once the steel solidifies, the Chromium at the surface of the steel instantly forms a layer of Chromium Oxide on contact with atmospheric oxygen. This microscopic layer of Chromium Oxide protects the body or the steel from further corrosion. It is almost like magic, that is the beauty of Stainless. Scratch it or cut it, and the Chromium at the new surface instantly forms a new layer of Chromium Oxide, protecting the metal from corrosion again.

The only fly in this ointment is tiny bits of non Stainless Steel that might get imbedded in the surface. Tiny bits rubbed off an cutting tool, or tiny shards of regular steel wool, will begin to corrode, and because they are imbedded in the surface of the steel, the Stainless Steel in contact with the contaminant will begin to corrode.

To prevent this happening, Stainless Steel is passivated once all the cutting and machining is done. Passivation consists of first cleaning the parts, to wash away any foreign metals, dirt, or grease. Then the parts are dipped into a passivating acid bath. There are different baths for different types of Stainless.

The bottom line is, if you want to polish your Stainless gun, DO NOT use standard steel wool. Particles can break off as I described, imbed themselves in the surface, and begin to corrode the gun. There are products made specifically for polishing Stainless Steels that will not harm the steel.


Here is an article describing passivating Stainless Steel:

http://www.mmsonline.com/articles/how-to-passivate-stainless-steel-parts

I love learning stuff like this. Thank you.

No, simple handling does not remove the layer of Chromium Oxide. Yes, excessive holster wear will, but as I said, the Chromium is everywhere throughout the metal. If the surface gets scratched, nicked, or worn, the Chromium instantly oxidizes, protecting the new surface. It really is almost like magic.

You might look into Scotch Brite pads or cloths. They will remove the matte surface more quickly than your microfibre polishing cloth. Then go to the microfibre after the Scotch Brite. Try polishing on a surface that will not show, like under the grips, before you tackle the entire gun. Don't forget to mask off any details you do not want polished away. Some of the laser marking on modern Smiths is very light, and could be easily polished away.

Good info in this thread.

I've used Mother's Mag polish with good results on my Smiths.

Another Mother's stainless polisher here. Microfiber works great.

MikeJackmin said:

I love learning stuff like this. Thank you.

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Me too, MikeJackmin!

Another thank you to Driftwood.

I used just scotchbrite (green) on a 4566TSW slide and it came out great!
Wasn't particularly intrested in really shining it up, just getting rid of some surface wear and that goofy "tactical 45" billboard.

Scotchbrite gray will polish or clean up stainless. It's less aggressive than green. You can find it in auto parts stores.

Nice job Driftwood. Thanks!

Hammer059 said:

Glad to hear Mother's has worked well for you, Kodiak.

How did you go about polishing it? Microfiber cloths? Scotchbrite pads then microfiber?

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I just throw in a movie, put a large towel on my lap so I don't get the polish on my furniture, and use a terry cloth towel to rub the polish on.

You just keep rubbing until the stuff turns black, and then wipe clean. It isn't difficult, but it does take some time. If you have the time though, like maybe over winter, it's kind of fun. I have never been able to bring myself to take a Scotchbrite pad to any of my guns though. I like a certain level of shine and then I stop. That way as scratches come up here and there, I can polish them out. I've always worried I'd go too far, too fast using one of those.

As an interesting note on stainless and aluminum, aluminum also instantly forms an invisible protective "film" that prevents the metal from corroding.

One thing to watch out for with stainless or aluminum guns is bead blasting them.
If you bead blast in a blaster that's been used to do carbon steel, the high pressure will carry tiny particles of carbon steel and embed them into the metal.
These carbon particles can rust later, damaging the stainless or aluminum.

I once had a customer who bead blasted an aluminum pistol frame in a garage bead blaster that was used for car parts.
He was astounded when his aluminum frame started rusting.

If you ever have a stainless or aluminum gun part bead blaster, either make SURE the blaster is cleaned out and refilled with all new blast media, or make sure it's a blaster used only for stainless steel.

I'd warn that all too often some gunsmiths will tell you they use a special blaster or promise to use clean media, but too many of them don't and just figure you'll never know, and if you find rust later they won't admit responsibility.

Interesting thread. I found this Model 66 (no dash) not long ago. This image doesn't really show how flat the exterior looked.



I took it home, removed the grips, and did a couple of coats of Flitz (paste) (put it on with a finger, took it off with an old T-shirt). Then a couple of coats of automotive paste wax, applied and removed the same way. Now, I admit the light is a lot better in these pictures.





The pictures don't show it, but it even took the blast rings off the front of the cylinder. It took maybe 30 minutes to do the job.

Another fan of Mother's Mag Polish. Easy to use and all that required is a soft cotton cloth and lots of elbow grease!

So is stainless steel wool stainless? Plain old Wal-Mart bought stuff?

I just had deviated septum surgery yesterday and I intend on cleaning up a GP100 today (ex-Canadian police tradein) and make it shiny and new. It has lots of scratches but is tight and shoots true.

Deaf

I know of no "stainless" steel wool. The Walmart stuff will rust. Scotchbrite avoids the rust issue--or just polish with a soft cloth.

Here is my SP101. This level of shine probably involves about 10 hours of work and ten polishing sessions in front of the tv with Mother's.

460Kodiak

Nice work on the SP101. Like the holster too!

That's the "Celtic Knot" carving from Simply Rugged holsters. I have the same pattern in all my SR's.

I join bannockburn in saying very nice gun/holster combo.

I polished one of mine about 7 or 8 years ago, it came out looking almost like a nickel, wish I hadn't done it. No doubt it brighter and very shiny, but finger prints show up very easily now.

As for being prone to rust, I haven't had any issues, and mine gets carried almost daily, and has often been exposed to rain, nothing has happened so far.

So if this is what you want, go for it, just know that it will look like a nickel finish when you get finished.

GS