Aluminum, Steel, and Electrolysis

[Monac]

I was reading this article:

http://www.pyramydair.com/blog/2014/11/the-cody-thunderbird-revolver-the-face-of-innovation/

about an inexpensive 22 revolver call the Cody Thunderbird, which was produced for a short time in the late 1950's. This paragraph kind of stopped me:

"But the final flaw is the most serious, because it affected every gun that left the factory. The gun’s frame is aluminum and the action parts are steel, which set up electrolysis in each and every gun! Without fail, all the parts were welded together over time. Every gun will have this problem. The only solution is disassembly, cleaning and protection with something like Ballistol."

There are a lot of aluminum alloy framed revolvers and semi-autos out there, and most of them have steel action parts, but I have never heard of this. Is it a real problem?

I have forgotten WAY too much about basic science to say whether aluminum and steel would react together to create electricity and corrode each other. Also, just to nitpick, I would have thought the proper term was galvanic reaction, and not electrolysis.

 

[Tcruse]

Not sure, but there are a lot of differences between different alloys of aluminum and steel. So, I do not expect to see the problem with my Ruger 1911 light weight ever.

 

[Speedo66]

Old style Land Rovers used to run onto this problem with their steel frame and aluminum bodies. Lots of corroded aluminum due to electrolysis.

 

[Acera]

Lots of homes have developed water leaks when copper pipes touch a steel nail, and electrolysis eats a hole in the copper.



.

 

[RX-79G]

That sort of galvanic reaction usually takes water to complete the 'circuit'.

I wonder if these pistols had un-anodized aluminum frames. That would contribute.

 

[BCRider]

Anodizing helps but only a little. But as mentioned it takes water mixed with something like the salt in hand sweat to complete the connection and provide the electrolyte. If the alloy and steel are kept correctly oiled and in dry enough conditions for the steel to not rust then there won't be any electrolysis.

If this were not the case you'd have an awful lot of unhappy Sig owners crying themselves to sleep at night. And similarly Ruger Lite owners, Ithica and Mossberg shotgun owners and others. Oh yeah, and Ruger 10/22 owners since those all come with alloy receivers as well. The legions of crying gun owners would include me as well as I'd be crying over my seized up S&W 422 if this were an issue.

The person that wrote that article apparently doesn't know as much as one would sort of expect for writing articles about guns.

 

[BobWright]

The only time I ever saw any evidence of that was a shotgun brought to me that had been in a flood. The aluminum magazine follower welded itself to the steel magazine tube. But Ruger Blackhawk revolvers have had aluminum grip frames and ejector rod housings for many years with no ill effects.

Bob Wright

 

[Monac]

The necessity for water, or some other electrolyte, to complete the circuit (and justify the name electrolysis) makes sense to me. Thanks, all!

 

[bannockburn]

Never have seen anything like that having owned quite a few steel slide/aluminum framed semi-auto handguns. But then again none of them have ever been near any water either. I have heard of where some all steel pistols (where both pieces are made of the same steel), can have problems with excessive wear along the slide and frame rails.

 

[45_auto]

Here's a question for you guys, can anyone explain the difference between electrolysis and galvanic corrosion?

 

[200Apples]

...can anyone explain the difference between electrolysis and galvanic corrosion?

Why, yes! Go0gle says:

What is the difference between electrolysis and galvanic corrosion?

Without getting into a chemistry lesson, electrolysis involves only one metal and a major change occurring in an electrolyte, that being a liquid with chemical properties that make it capable of conducting an electrical current. A good example would be when a lead-acid battery discharges and produces a major change in the concentration of the battery acid, which is the electrolyte.

Galvanic corrosion involves two dissimilar metals, where the major change occurs in the metals and not the electrolyte. Here the best example is immersing your boat’s bronze props and stainless steel shafts in sea water, which acts as an excellent electrolyte. With the two metals in direct contact with each other, and the salt water able to conduct electricity, an electrochemical reaction causes the flow of ions to attack and dissolve one of the metals. And as all metals have potential energy in the form of trapped electrons, these electrons migrate from metal to metal. The corrosion takes place because the metals have different electrical potentials. (The Galvanic Series of Metals in Sea Water chart, also known as the Galvanic Scale, lists the most-active to least-active metals.) In our example, the current will flow from the bronze, which has a relatively high electrical potential and is therefore the anode, to the stainless steel, possessing a lower potential and thus taking on the role of cathode. The result is corrosion of the props.

More here: http://www.powerandmotoryacht.com/refit-and-upgrade/there-difference

Additional Go0gle Search Results: https://www.google.com/?gws_rd=ssl#q=electrolysis+vs+galvanic+corrosion

 

[Reloadron]

The gun’s frame is aluminum and the action parts are steel, which set up electrolysis in each and every gun!

While the Wikipedia is not always the best source of information their definition of electrolysis sort of runs with how I remember the process.

In chemistry and manufacturing, electrolysis is a technique that uses a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separationof elements from naturally occurring sources such as ores using an electrolytic cell. The voltage that is needed for electrolysis to occur is called the decomposition potential.

Complete Wiki Link.

So I guess the question becomes what is the source of the Direct Current (electricity) for the electrolysis to take place? Additionally, as was mentioned, there are dozens of alloy frame (aluminum) guns out there with steel parts.

Ron

 

[MachIVshooter]

Galvanic corrosion is a real concern in may applications, but not so much with guns. As mentioned, it requires electrolyte. Generated electrical current through the parts will also exacerbate the reaction. Both are frequently present in things like automobiles and aircraft, so steps need to be taken to prevent it (dielectric barriers). But guns don't tend to be subjected to the kind of moisture vehicles are, and the generation of electrical current through the parts is far less with static electricity only and not that much of it (one of the reasons you'll see ground straps in weird places on vehicles). Guns also tend to be oiled, and most oils are not conductive, so this also limits the effects.

ARs may be the best example, with completely aluminum receivers housing carbon steel bolt carriers, pins and fire control parts, and mated to steel barrels with steel barrel nuts, steel receiver extensions, steel latches in aluminum charging handles, etc. Yet after more than a half century of the AR's existence and tens of millions of units, many having existed in pretty harsh environments, we really don't hear about galvanic corrosion issues.

Lots of homes have developed water leaks when copper pipes touch a steel nail, and electrolysis eats a hole in the copper.

I would bet that has a lot more to do with vibration of the pipe causing the steel nail to wear through the soft copper than electrolysis ;-)

 

[Monac]

I wonder what field the author of the article I quoted works in? He knows that two dissimilar metals can cause an electrical/galvanic/electrolytic reaction, which is not something everyone would think of, but he does NOT know that it has never been a problem in pistols. Strange. Still, except for that glitch, it seems like a very good piece about the pistol.

 

[flightsimmer]

I used to see this a lot in the winter when I serviced semi trailers.
They would be wet with road salt and you could see the foaming and bubbling along the joints between the steel and aluminum, it would literally eat it up.

 

[bobinoregon]

I am going through this with my jet boat right now. Aluminum hull with a bronze water filter bolted to it with a stainless bolt, ate a hole in the aluminum around the bolt. The worst part is I've spent the last 20+ years making a living in the cathodic protection industry so you would think I would be watching for that situation. I'd think having no electrolyte present with a gun there shouldn't be much problem

 

[Monac]

Me too, bobinoregon. Perhaps the author who thought aluminum guns with steel lockwork would have big problems with electrolytic action was familiar with boats rather than firearms.

 

[Gaucho Gringo]

Probably a non issue also but what about the different expansion and contraction rates of dissimilar metals in guns? I would suppose the manufacturers would engineer the tolerances to compensate.

 

[Reloadron]

Probably a non issue also but what about the different expansion and contraction rates of dissimilar metals in guns? I would suppose the manufacturers would engineer the tolerances to compensate.

I would guess it is all figured in and you would have to look up the expansion coefficients of the alloys. All in all in the end I doubt it matters much but obviously it is there. Metallurgy was not my calling but a good metallurgist is worth his or her weight in gold when you need one, like a chemist.

Ron

 

[barnbwt]

Hexavalent chrome for the win. Dissimilar metals corrosion can be delayed with a sacrificial anode (zinc, cadmium, hex-chrome) coating or finish, or blocked with a prophylactic like paint or grease that disrupts the electrical circuit, or reduced by choosing more compatible alloys in the first place. On aircraft (where this is a seriously big issue with aluminum frame elements & stainless/steel/titanium fasteners) the metallic coatings are preferred, though they also have very serious toxicity issues. We're not exposed to it in my industry just yet, but I understand carbon fiber is literally the worst material there is for corroding anything metallic that's put through it as a fastener; perhaps something to consider for all those fancy handguards out there

ARs may be the best example, with completely aluminum receivers housing carbon steel bolt carriers, pins and fire control parts, and mated to steel barrels with steel barrel nuts, steel receiver extensions, steel latches in aluminum charging handles, etc. Yet after more than a half century of the AR's existence and tens of millions of units, many having existed in pretty harsh environments, we really don't hear about galvanic corrosion issues.

What's weird is seeing them still intact even in states of neglect for decades in the middle east. Considering a heavy girder for a lower airframe area will be flaking apart well into its cross section due to corrosion after a couple decades of exposure to condensation at altitude, it's always surprised me this isn't a bigger issue with ARs or autopistols in these areas. At least on aircraft, a big contributing factor is 'stress corrosion,' where flexing of parts opens up microcracks to oxygen infiltration & corrosion; guns aren't kept in a state of flex long enough (at a time, or in total) for this to be a big issue outside of magazine lips, so perhaps that slows the process down more.

Probably a non issue also but what about the different expansion and contraction rates of dissimilar metals in guns? I would suppose the manufacturers would engineer the tolerances to compensate.

Experience with aluminum household wiring would indicate otherwise (that engineers necessarily account for these effects)