Guns Rusting in Safe

[Wolf777]

This thread has turned out quite interesting. Slightly different but still to do with corrosion prevention. I am currently testing coating my bullets and barrels with Hex-Boron Nitride and couldn't find a definitive answer with regards to treating your barrel with the HBN and alcohol solution. I stumbled upon this paper which suggests it might actually help with corrosion resistance which I found interesting.

Link to HBN coating:

Link to paper:https://www.nature.com/articles/ncomms3541

[Againstthegrains]

This thread has turned out quite interesting. Slightly different but still to do with corrosion prevention. I am currently testing coating my bullets and barrels with Hex-Boron Nitride and couldn't find a definitive answer with regards to treating your barrel with the HBN and alcohol solution. I stumbled upon this paper which suggests it might actually help with corrosion resistance which I found interesting.

Link to HBN coating:

Link to paper:https://www.nature.com/articles/ncomms3541

I had a brief look through both links, and I think these are almost two different things. The video suggests that the HBN is used as an added lubricant, the same way you would use graphite powder in a lock. The second article uses a high pressure technique to coat (crystalize) a single layer onto a surface. I do not think that the above video/coating kit is able to achieve what the article does as per the quality of the coating.

On a very cynical note, I reckon if you tumble soft copper bullets for that long with stainless steel media, they are bound to erode down a bit so that the smaller diameter bullet will naturally reduce pressure

[DLRX]

What is your take on nitrogen-rich steels, like H1 that Spyderco uses in some of its knives?

Without a H1 material certificate I will base my comments on what I read on the composition of H1.
Corrosion resistance:
H1 basically has a estimated 13 to 15% Cr content. Cr is one of the main contributors to corrosion resistance and compared to the following common grades of SS
304 Cr +- 18% +8% Ni
316 Cr 16 to 18% 10%Ni and 2% Moly
904(Superior in corrosion resistance) 19 to 23% Cr 23 to 28% Ni and 4% Moly
Nitrogen does increase corrosion resitance yet at the cost of resduced amounts of Cr ,Ni and Moly.
Some studies indicate that the the Nitrogen rich steels show increased corrosion resistance compared to 18 Cr grades ( 304 ss) yet others is quite the opposite.
Remember by increasing Nitrogen content on have to reduce other alloying elements to accomodate the increased volume of Nitrogen. By substitution one gain some of the corrosion resistance that increase in Nitrogen offer at the expence of lower Cr, Ni and Moly. As a material used on knives one should consider other factors like hardness and toughness and therefore the H1 is acceptable.
Look I can carry on and discuss work hardening and the ability to sustain its "edge as a cutting tool" but I suspose we discuss corrosion?
As a barrel one would need toughness and increased mechanical properties without being brittle (tough and strong)

[DLRX]

My guess is galvanic corrosion due to a humid environment with copper fouling. I am of the opinion that it could have been prevented by a simple application of proper gun oil.
[/QUOTE]

I am not convinced that it is Galvanic corrosion even if it plausible?
For galvanic corrosion we need the following:
*2 different materials with different corrosion potential - SS and Brass/copper.
*Electrolyte to connect the two matetials in a "conductive path"-moist air.
*Direct metel to metel contact- direct copper contact in the barrrel.
For the galvanic series one material is the anode and the othe the cathode. The one anodic (active) metal will be the anode and the most noble will be the cathode. The driving force for electron flow( galvanic corrosion) comes from the potential between the anode and cathode combined with the potential presented by the suspended electrolyte to conduct ion exchange /electron flow.
Copper and Stainless are very close in galvanic series. In this cases there is zero to almost no difference between the 2.
Staineless seem to be a susceptible cathode compared to 70/30 brass. In other words based on marerials one would expect very low to almost no current flow.
Secondly The electrolyte is also not submerged...air is general an isolator and therofee increasing the resistance against electron flow (ion exchange) Moist air can certainly be an electrolyte yet the rifle was in a safe not in the elements?
Lastly the contact area of copper fouling is over the complete bore of the barrel.This will reduce the corrosion rate of the galavanic cell. If the area of the cathode is large and the anode small the current produced will be likely to be high.
In this case we have large contact areas and therefore o e would not likely see the localised corrosion/pit as shown in the photo...
Oil willdefinitely stop galavanic corrosion...by isolating the material from flow of current to the electrolyte.

[Skaaphaas]

Without a H1 material certificate I will base my comments on what I read on the composition of H1.
Corrosion resistance:
H1 basically has a estimated 13 to 15% Cr content. Cr is one of the main contributors to corrosion resistance and compared to the following common grades of SS
304 Cr +- 18% +8% Ni
316 Cr 16 to 18% 10%Ni and 2% Moly
904(Superior in corrosion resistance) 19 to 23% Cr 23 to 28% Ni and 4% Moly
Nitrogen does increase corrosion resitance yet at the cost of resduced amounts of Cr ,Ni and Moly.
Some studies indicate that the the Nitrogen rich steels show increased corrosion resistance compared to 18 Cr grades ( 304 ss) yet others is quite the opposite.
Remember by increasing Nitrogen content on have to reduce other alloying elements to accomodate the increased volume of Nitrogen. By substitution one gain some of the corrosion resistance that increase in Nitrogen offer at the expence of lower Cr, Ni and Moly. As a material used on knives one should consider other factors like hardness and toughness and therefore the H1 is acceptable.
Look I can carry on and discuss work hardening and the ability to sustain its "edge as a cutting tool" but I suspose we discuss corrosion?
As a barrel one would need toughness and increased mechanical properties without being brittle (tough and strong)

Thanks. From personal experience I can tell you it is incredibly corrosion resistant. To the point where I sometimes think this thing cannot rust!
And it is a tough steel, in the sense that the edge will roll before it chips, but it’s not very hard and wear resistance isn’t great.

As you say, speaking about barrels, I just wondered if it would be suitable. But it’s probably overkill in terms of corrosion resistance while sacrificing other more desirable elements.

[DLRX]

As you say, speaking about barrels, I just wondered if it would be suitable. But it’s probably overkill in terms of corrosion resistance while sacrificing other more desirable elements.[/QUOTE]
H1 is susceptible to work harden and therefore wont be best suited as barrel material.
Consecutively firing rounds with pressure and abrasive wear can contribute to premature failure if the material strain/work hardens. As a blade it actually increase its ability to keep its edge (the more one use it the longer it will keep its edge)

[Skaaphaas]

As you say, speaking about barrels, I just wondered if it would be suitable. But it’s probably overkill in terms of corrosion resistance while sacrificing other more desirable elements.

H1 is susceptible to work harden and therefore wont be best suited as barrel material.
Consecutively firing rounds with pressure and abrasive wear can contribute to premature failure if the material strain/work hardens. As a blade it actually increase its ability to keep its edge (the more one use it the longer it will keep its edge)

Very interesting.
Metallurgy seems to be a dark art!

[SafeAction]

Very interesting. Metallurgy seems to be a dark art!

That’s why it started back in the day with blacksmiths, until science came along.:-D

[Wolf777]

I had a brief look through both links, and I think these are almost two different things. The video suggests that the HBN is used as an added lubricant, the same way you would use graphite powder in a lock. The second article uses a high pressure technique to coat (crystalize) a single layer onto a surface. I do not think that the above video/coating kit is able to achieve what the article does as per the quality of the coating.

On a very cynical note, I reckon if you tumble soft copper bullets for that long with stainless steel media, they are bound to erode down a bit so that the smaller diameter bullet will naturally reduce pressure

Yeah I agree with the fact that the application method is different, but should put a few minds at ease knowing that hbn on its own shouldn't rust your bore up. Hbn seems to be a great dry lube with the heat and pressures it can handle, but your cynicism is welcomed, I hadn't thought about the bb's that way. Although I do know they are not required, other methods just use a tumbler, rotary or vibratory, and bullets alone to impact coat each other.

[lookonimages]

Cape Town.

Another Fluidfilm user.
15 years never had rust.
Will never use anything else.

Bought it years ago direct from importer but I see Safari outdoor stock it.

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