SIG Sauer aluminum frames: Corrosion

[kozak6]

When I was a kid, my dad had some scrap aluminum on the side of the house.

It was outside in the rain and weather for years.

Some of the pieces had small speckles of white corrosion. That was about it.

Something weird happened here and we definitely don't have the whole story.

 

[oldengineer]

I don't know if the OP's story is correct as stated, but aluminum isn't corrosion resistant, and corrosion can occur with some combinations of metals. Some aluminum alloys are very susceptible to corrosion. (That's why some aerosol products come in steel cans, while other can come in aluminum.)

When I was in the Navy some years ago they built several classes of ships with aluminum superstructures riveted to steel decks. They were careful to try to minimize galvanic corrosion by inserting a thick layer of mica at the interface but it did not stop the problem from occurring.

 

[Rinspeed]

I emailed the link to a good friend of mine who is very sharp when it comes to most things regarding physics and metallurgy. He also owns a couple classic P series Sigs so I thought he might have some good input. As I stated before I know very little about galvanic corrosion but I have heard about it and have seen a couple instances where aluminum corroded with no clear explanation. I had thought an electrical field, such as a poor ground, was necessary but apparently this is not the case.

Interestingly enough no externally applied field is necessary. In a similar fashion to a thermocouple that sets up a voltage drop by virtue of two dissimilar metallic materials in contact with each other, here you have two very dissimilar metals in an environment that supports the kind of "flow of electrons" that lead to corrosion. Don't know if you are aware, it is common practice on bridges and ships to apply sacrificial strips of a metal, that is more easily corroded, to the structure. This will corrode preferentially over the superstructure as the chemistry is essentially all happening at that material. Once it is gone the structure starts to go.

 

[AxlMyk]

The sig looks like it's full of wood working dust.

 

[tipoc]

Yep there is more to this story than what is being told by the author's "good buddy PogMoThoin ". (Interesting name that, an anagram? Anyone ever see a name like that with three capital letters and no breaks? Not Thai, or Cambodian, well maybe I don't know all names of folks from there, or from Uzbekistan for that matter.). The damage done to both guns is not the result of guns simply stored in a foam lined case for a year in a dry closet in a very dry state.

It does look like the type damage seen in weapons recovered from the damp hold or bilge, of a boat where they are subject to periodic immersion in salt water and exposure to air for an extended period. Extended period, being not a few months but many months or years. If a chemical was involved, that reacts to aluminum, the process will be accelerated. The damage seen here, especially to the Sig where it looks like chunks of metal are missing, are not possible as a result of simply sitting in a "Honeywell Lockbox with foam padding" for 12 months.

The white crust that forms on aluminum after extended lengths of time exposed to the elements and dampness will wipe and buff right off but leaves the aluminum pitted. I've seen it often on stacked aluminum stored outdoors where rain water has seeped in between the stacked bars and been trapped for months or years. Where steel will rust under the same conditions aluminum will produce this crust.

Aluminum does react to salt water...so does steel. No one has figured how to make the slide and barrel of a gun without steel far as I know. This has not deterred the Navies and merchant fleets of the world from having firearms on board ships for generations and keeping them free of corrosion.

I went back and read the whole story again...reads like a piece written by an overactive Glock marketing associate. It take s a big swipe at Sig's customer relations folks. Read this bit...

I called Sig and spoke to their Customer Service department. I explained the backstory to an employee named Ryan and told him that I would like to purchase a replacement frame for the P229. Ryan said he could not sell me a frame since it was considered a firearm. I told him that I do understand it, but could he transfer it through my local Sig Sauer dealer? Nope, Sig does not sell frames he explained. I then asked him if I could send the pistol to Sig for them to fix it. Nope, they will not fix it. By now I was at a loss, it was clear that Sig had no interest in seeing this pistol operational again. I asked him what I should do, and he stated that I should sell the pistol for parts, and use the proceeds to purchase a new Sig Sauer pistol. I thanked Ryan for his help (or lack thereof) and hung up. Based off of my past experiences with Sig Sauer's customer service, I was not exactly surprised by their lack of wanting to do anything. I had called them in the past due to a Sig Mosquito being, well, simply a piece of -CENSORED--CENSORED--CENSORED--CENSORED-. I was told that it was normal, and they did not even want to look at it.

So a fella that does not own the gun calls Sig and gives them a very odd story on how the gun was damaged due to poor storage by their good buddy PullMeGroin and wants them to replace it or fix it and Sig says all they can do is sell them a new one and we should be irritated at Sig? Hmm?

tipoc