Verdigris

[fredk]

22 hours ago, RemingtonSteel said:

So just to be clear, your saying you don't like my pretty verdigris cartridges. I'll have you know that it took me well over a year of sitting on my butt waiting for it develop just to get it to this stage. Geez, either there is just no accounting for art appreciation, or turquois is not your most favorite color. 

That is interesting. I wonder if it has anything to do with the amount of copper in the alloy.

Last year a friend found two boxes of Mauser rifle cartridges. About 26 rounds total The boxes had been hidden in a dis-used chimney in a cottage. Papers with them indicated they had been put there about 1912. No verdigris on the shells, just dull tarnishing

[JamesRiley]

4 hours ago, fredk said:

That is interesting. I wonder if it has anything to do with the amount of copper in the alloy.

Last year a friend found two boxes of Mauser rifle cartridges. About 26 rounds total The boxes had been hidden in a dis-used chimney in a cottage. Papers with them indicated they had been put there about 1912. No verdigris on the shells, just dull tarnishing

I think it has something to do with the leather.  I've seen cartridges' that are more than a hundred years old in a cardboard box with no verdigris.  

[Davm]

I wasn't sure whether the verdigris adversely effected the strength of brass cartridges.  I polished my 45 Colt cases and used them- no problem but I then cut up wood dowels and keep them in the bullet loops. If you don't the loops tend to shrink and make it more difficult to put in cartridges. I have never found a way to stop verdigris so I sew more than rivet on my leather work.

[RemingtonSteel]

6 hours ago, Davm said:

I wasn't sure whether the verdigris adversely effected the strength of brass cartridges.  I polished my 45 Colt cases and used them- no problem but I then cut up wood dowels and keep them in the bullet loops. If you don't the loops tend to shrink and make it more difficult to put in cartridges. I have never found a way to stop verdigris so I sew more than rivet on my leather work.

There is Corrosion and there is Oxidation. 

Corrosion on brass generally happens when brass is exposed to water for long periods of time. It is generally identified by reddish or pink splotches on the surface.  Corrosion can and will weaken brass over time, so brass fittings on boats for an example should be cleaned, polished, and protected with a polyurethane or lacquer to protect them (but more often they are not.)

Oxidation on brass happens over time as the brass is exposed to air. Oxidation can appear as a blackish, green, or blue patina on the surface of the brass. The patina in no way diminishes the strength of the brass, and has the beneficial effect of actually protecting brass from corrosion. Verdigris is (a type of heave duty) oxidation that is accelerated by the brass being also exposed to certain acids. Verdigris can be natural or man made and is often purposefully applied to brass artwork to protect it from the elements. This explains why most boat owners do not worry about keeping their brass clean, polished and protected, as the oxidation does that for them.

So to answer your question, I wouldn't worry about the verdigris effecting the strength of brass cartridges.  They are going to be weakened more by the process of shooting and reloading, which is stretching and then compressing the brass, over and over again. Over time your casings will spit, which is why it is suggested that you only reload them a certain number of times.  The bigger concern as stated by JamesRiley is do you want this gunk in your firearms?  Might be OK in a revolver, but I definitely would not want to run it through my lever action rifle.

Regarding the use of rivets... Not really sure it matters either way... personal preference I think.

I made this shell belt about three years ago.  This particular set of cartridges have been sitting in the loops for just over a year due to covid. As you can see lots of verdigris in just one year, but look at the copper rivets that I used to secure the loop ends to the belt. Almost three year in the same leather, and they are as shinny as the day I put them in.  I am not a chemist or metallurgist, so I can't explain why... maybe something to do with the zinc that is in the brass. Bottom line, there are plenty of old rigs in the book Packing Iron where the makers used rivets in addition to sewing on the billet and buckle straps for extra strength, and they have stood the test of time... so put em in if you like them or leave em out if you don't.

 

[765x53]

Verdigris, also known as "grave mold", is caused by contact with animal fat, mink oil , neets foot oil, tallow, etc.  Dry vegetable tanned leather will not be effected.