Evaporust on Stainless?

[RickinTN]

Hello all,
I have a couple of stainless 1911's which are rusting, yep, I know. That's one reason I bought stainless to begin with. I have never used Evaporust but have read good things about it. When used on stainless are there any problems or issues? Will it stain the steel? or anything unwanted?
Thanks for any help and advice you might be able to offer,
Rick

[DocSavage]

Don't know how evapqorust will react to stainless but I can tell that the SS used in firearms is rust resistent not rust proof. A truly rust proof stainless would be to brittle for use in firearms. Try some bronze wool to remove the rust you can get that a boating supply store,after cleaning use some car polish to protect the metal. Mother's mag polish might work as well.

[RickinTN]

The rust is in a matte part of the slide and also in the serrations. I have bronze wool but haven't tried it. I'm thinking it may work in the serrations, but would be hesitant to use it in the matte section as I don't want to have a spot in the matte finish which would look different. That is the primary reason I'm looking to remove it chemically if I can.
Thanks for your response,
Rick

[M-Tecs]

Most firearms using stainless use a 416/420 or 630 (17-4) stainless steel. It will be magnetic. Non-magnetic stainless steel is far more corrosion resistant but it generally not heat-treatable. As such they are too soft for most firearms applications.

Evaporust works great but you it tends to give a mild color change to the base metal. I am color blind so I could be of on the color change but it appears to me to turn a darker shade of gray. That being said I have never used it on SS.

One of the more common causes of rust on SS is using ferrous steel wool. SS should never be touched with the normal ferrous steel wool. Bronze or stainless steel wool is fine.

Matte finishes tend to be glass bead blasted.

200 and 300 series stainless steel are austenistic, which means they are not magnetic but 400 is

You generally can tell grade by application. 200–300 are used in things that don't need to be hardened and need a high level of corrosion resistance.

400 series are mostly magnetic and heat-treatable. For cutlery 440C is widely used. 416/420 are commonly used in firearms.

630 stainless is 17-4. It's very common is firearms.

[GregLaROCHE]

You can use a solution of HCL. Start slowly without too strong of a solution. Increase it as you see fit. Many rust removal products have additives to convert the surface to protect it from re-oxydation. They tend to turn the surface a blue to dark grey. Use only on affected areas. It could tend to etch a polished surface. Also the metal must be grease and oil free. I like brake cleaner for that.

[john.k]

Not criticising,but I would not put HCl anywhere near a 400 grade stainless.....in fact the chloride ion will attack the chromium in steel very freely,these steels are resistant to oxidation ,not chloride attack.......The method of cleaning up welded food grade stainless uses a mix of nitric and hydroflouric acids in a dip or gel ,but I would not not use this on a 400 grade either.

[JimB..]

Evaporust will leave it gray, you’ll want to clean that off and it’s not hard, but it may affect the finish. I’d be tempted to take a piece of comparable stainless, maybe a muzzle protector for a threaded stainless barrel or even a piece of old barrel, and try soaking it and then ultrasonic cleaning to see if the gray comes off and how it affects the finish.

[Iowa Fox]

I think the only way to do it right is to vapor blast the slide. Anything else will wind up looking look like heck. I'm not sure what brand of 1911s but I would contact the manufacturer if they are in the US and tell them what you have. A slide is mailable. If they won't help you I'd check with one of the well known pistol smiths. Bead blasting is to course to product a nice factory appearance.

[M-Tecs]

Bead blasting is to course to product a nice factory appearance.

As to coarseness of the finish that is a function of glass bead size, distance to work and the pressure used. Vapor blasting and glass bead blasting can and do produce the same finishes. Vapor blasting has several advantages in a production setting but I am not aware of any smaller smaller shops using it.

https://www.raptorblaster.com/glass-bead-size-chart/

https://www.guyson.com/guyson-blast-blogs/blast-media-and-applications/cosmetic-finishing-by-bead-blasting/

[EDG]

Working with stainless steels was part of my engineering duties for many years.

The gun companies may not be very well informed about the different materials or about passivating them.

There are about 3 potential problems when you get a little rust.

1. The material is one that will rust because it is not highly rust resistant - 416 used for rifle barrels is one of those. Those alloys need to be kept clean and oiled.

2. Your material was never passivated. Stainless steels will show staining and light rusting when carbon steel is smeared on the surface of the parts. This smeared on steel can come from high speed steel cutters, milling machine vise jaws or contact with things like fork lift forks.
To get rid of this smeared on steel and make the surface of the stainless inactive you can use a 20% solution of nitric acid (or some concentration of citric acid which I do not recall).

3. Your material was bead blasted in a carbon steel cabinet. The beads fly past your parts and strike the cabinet and pick up steel residue. The next time the beads are shot at and hit your parts they deposit microscopic smears of carbon steel. That residue can rust and stain your gun parts. So they need to be passivated in nitric or citric acid.

4. Some heat treated stainless steels will rust due to mediocre heat treating or poor passivation. The material may be hard enough but it may rust anyway. 440C tends to do this if it is not cleaned well before passivation. To get it clean often requires another process called electropolishing.

Do not try to passivate carbon steel as the acid will turn it black. Small carbon steel parts will dissolve in the acid.

Basically passivation gets rid of the steel on the surface. The acid destroys the free iron but cannot dissolve the alloy of chrome, iron and nickel that makes up stainless steels.

If you can find a copy of the Carpenter Blue Book of Stainless Steels on line it will give you all the gory details of passivation.

[winelover]

If all else fails, Ceracote it.

Winelover

[Greg S]

I would mask and reblast the surfaces with clean abrasives and care for as blued steel.

[GregLaROCHE]

Not criticising,but I would not put HCl anywhere near a 400 grade stainless.....in fact the chloride ion will attack the chromium in steel very freely,these steels are resistant to oxidation ,not chloride attack.......The method of cleaning up welded food grade stainless uses a mix of nitric and hydroflouric acids in a dip or gel ,but I would not not use this on a 400 grade either.

I don’t doubt you know more it than me. I was told about it years ago and used it to clean up SS in a marine environment. Hosed it off with fresh water afterwards. From what you have said, I wouldn’t do it again.

[john.k]

GLR, my comments are for a gun,a marine fitting is sure to be a chloride resistant stainless ,so the acid wont hurt it...For the gun,I would go with the wet bead blasting,but using new beads .