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I am looking to snag a Gold Cup Trophy that has some super light and fine rust in the beaded areas. Short of taping off the brushed/polished areas and reblasting the slide and frame both, which technique do you think would work best on the rougher areas? Pic of damage… View attachment 648701
View attachment 648700
 

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This has been discussed before. Drop the affected parts in a solution of citric acid and water. The rust will fall off in a couple hours w/o damaging the metal.
 

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Removing rust from stainless steel is called passivation. In the machine trades it's a common process. Stainless isn't machined with stainless steel cutting tools. They are machined with High Speed Steel cutting tools which are high carbon steel. It the machined surfaces are not passivated after machining these surfaces will rust.
 

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How does one passivate?
Stainless Steel is still primarily iron, that will rust, except stainless steel contains Chromium and Nickle that creates a Chromium Oxide layer on the surface when exposed to oxygen to prevent rust. That is what is Passivation.

I don't know if machining from Carbon Steel tools, if not passivated, can cause surface rust, I have no reason to doubt that assertion, but depending on the alloy, conditions and circumstances, sooner or later rust will appear on stainless steel. Clearly, cutting away the old oxidized surface to create a fresh one, would remove the original passivation. I don't know if the contact with the carbon steel during the machining might do something to leave carbon behind, or stave off the natural process of passivation.

I've seen stainless steel rust, heck, the O.P. is photos of rust on stainless steel. Usually its exposed to heat, salt or chlorine that I've seen rather rapid rust, but still far slower rust than carbon steel under the same condition. So I don't know if stainless steel always rust, just much slower than other steels, or if its a matter of it only rusts if the passivation is compromised or prevented by the conditions.
 

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Stainless Steel is still primarily iron, that will rust, except stainless steel contains Chromium and Nickle that creates a Chromium Oxide layer on the surface when exposed to oxygen to prevent rust. That is what is Passivation.

I don't know if machining from Carbon Steel tools, if not passivated, can cause surface rust, I have no reason to doubt that assertion, but depending on the alloy, conditions and circumstances, sooner or later rust will appear on stainless steel. Clearly, cutting away the old oxidized surface to create a fresh one, would remove the original passivation. I don't know if the contact with the carbon steel during the machining might do something to leave carbon behind, or stave off the natural process of passivation.

I've seen stainless steel rust, heck, the O.P. is photos of rust on stainless steel. Usually its exposed to heat, salt or chlorine that I've seen rather rapid rust, but still far slower rust than carbon steel under the same condition. So I don't if stainless steel always rust, just much slower than other steels, or if its a matter of it only rusts if the passivation is prevented by the conditions.
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I am looking to snag a Gold Cup Trophy that has some super light and fine rust in the beaded areas. Short of taping off the brushed/polished areas and reblasting the slide and frame both, which technique do you think would work best on the rougher areas? Pic of damage… View attachment 648701
View attachment 648700
Under NO CIRCUMSTANCES use steel wool on stainless steel.
 

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Carbon steel dust can get into the pores of stainless i would imagine and cause rust. Bare steel will rust in 24 hours if left untreated in a hot humid environment. Op's gun was an abused child. No reason for that. Store lubed, no rust.
 

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How does one passivate?
Commercial processes for passivation are more complex, but when I want to play with the mind of a Consulting Engineer who never played in the sandbox, hunted, fished, or gardened. I tell him/her that flat diet Mountain Due will passivate stainless welds. For cleaning off water/wastewater treatment equipment made out of 304 or 316 Stainless, a 10% citric acid solution works great. A lot of 1911 stainless parts are 416 or 416R and citric acid works well. If you don't want to buy any chemicals or Citric acid based Snake Oil, a few drops lime or lemon will do the trick, you can put the rest into your adult beverage, tea, or use it with your food. After you sharpen a stainless steel knife, cut a lime or lemon with it, that will passivate the cutting edge.
 

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Carbon steel dust can get into the pores of stainless i would imagine and cause rust. Bare steel will rust in 24 hours if left untreated in a hot humid environment. Op's gun was an abused child. No reason for that. Store lubed, no rust.
Does that do anything to the stainless steel, other than cosmetic, with the carbon steel rusting on the surface? I imagine it "could", but don't know, rust is an electric process, so something rusting in contact with something else starts a rusting process as the electrons from the chemical reaction flow through it, sometimes it prevents the rust process.
 

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BTW, I have been Cerakoting Stainless Steel in two pistol projects I'm working on. I have blasted the stainless steel with virgin aluminum oxide to prep the surface for Cerakote. DIY'ing it, I have blasted all the parts, but didn't get back to actually cerakoting to several days later. When this happens, I notice those parts the bright silver but rough surface has dulled a bit. I go back and blast it again, and the surface roughness remains the same but the color is a brighter silver again.

So, what I think I am seeing here is the natural passivation happening while the freshly blasted surface is left out exposed to oxygen for several days.
 

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Good quality Stainless should not rust !
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Someone who has not read the above 18-messages, especially #10.
 
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