"Blood Marks"... How to tell???

[Jean-Loup]

The "blood pitting" is an other collector myth.

In fact I once had cut my finger, and put several drips of blood on a mauser part I had, left it that way for several years, and did not observe any effect.

Having said this, it seems to me that when certain "substances" are left in contact with metal long term, they cause the metal to rust, probably by "capturing" humidity.
A good example of this is helmet covers, that when left on the helmet usualy cause quite a bit of rust to form.
I have observed that other subtances like mud, dust, blood, contact with leather, etc, if left on metal could cause it to rust faster on the long term.

So if you see "blood pitting", maybe it is blood that caused it, but most likely something else.

That is a great japanese machine gun someone posted. But you should put it back in original condition. What is the point of having it partly left as such, and partly with replacement parts?

JL

[Jean-Loup]

" Blood is very corrosive. If it is left on the weapon for a period of time exceeding a day or two you have a chance of a stain forming. It doesn't happen all of the time by any means. It requires a set of circumstances (just like how fossils are formed, everything has to be 'right')"

I am not a chemist, so could be wrong in this as I know chemistry is a very complicated topic. But, fresh blood has a pH slightly above 7, and is virtualy neutral. I doubt that it becomes "highly corrosive" as it dries and decomposes.

Faire enaugh, blood can leave traces, but so can simple fingerprints, and basicaly anything else that can be in contact with the metal as I said before: mud, etc.

JL

[Alan Smith]

Jean-Loup,

I swaped parts out on the Japanese MG so that I could get it up and running. It is now a live, fully-functional (and legally registered) machinegun. While its true value to me is as a collector piece, it is also quite a thrill to shoot live ammunition in a real WWII Japanese machinegun that, as far as I can tell, is an actual combat veteran of the Pacific Theater of Operations. Such shooting events (IMO) literally make history "come alive" in your hands.

I have all of the original parts and could put them back in place in a hour or so of tinkering in the workshop. For now, I leave it in functional condition (for periodic machinegun shoots with friends) and have the bullet and/or schrapnel damaged parts in a display case in my little "war room" at home.

If I get a chance, over the weekend I will take some better close-up photos of the damage to the gun's finish and post them here (if anyone is still interested).

Alan

[Ronnie Fry]

Alan,
Post away, Sir !! I love your MG....

And many, many thanks to you all for your input. Most interesting

We are all learning here...

Hoof Hearted !!

[Jean-Loup]

"If I get a chance, over the weekend I will take some better close-up photos of the damage to the gun's finish and post them here (if anyone is still interested)."

Yes, I would love to see some more photos of the missing pieces, and can you also post some photos of the bullet damage from other angles?

I understand shooting a machine gun must be pretty fun. But I find it a bit sad to use such a seemingly historicaly significant gun for shooting. But maybe that is just me, and many would find a mint gun more valuable then this battle damaged gun.
Anyways, as long as you keep all the pieces, no real harm is done.

JL

[Ronnie Fry]

Yes, Jean, photos PLEASE..

I figure the more photos, the better!!

Sal Hapatica

[Luis22]

I dont think the blood pitting issue is a myth ...I read that several of the WW II guns that have been chrome plated (mostly pistols) were done because of blood stains to the bluing of the gun..

[Gary Cain]

Hello J-L,

Take a look at the care the Japanese take of their swords. Simply touching them will cause rust. I have a 400 year old sword where you can clearly see the stains left by the persons fingers who held it 60 years ago. Whenever weapons are handled they are immediately wiped down by a silicon cloth or similar cleaner. There is a reason why this is done. Now don't you think that blood will cause more damage than your fingers?


Cheers
Gary

" Blood is very corrosive. If it is left on the weapon for a period of time exceeding a day or two you have a chance of a stain forming. It doesn't happen all of the time by any means. It requires a set of circumstances (just like how fossils are formed, everything has to be 'right')"

I am not a chemist, so could be wrong in this as I know chemistry is a very complicated topic. But, fresh blood has a pH slightly above 7, and is virtualy neutral. I doubt that it becomes "highly corrosive" as it dries and decomposes.

Faire enaugh, blood can leave traces, but so can simple fingerprints, and basicaly anything else that can be in contact with the metal as I said before: mud, etc.

JL

[Jean-Loup]

Hi Gary<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o></o>
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I was not challenging you on the fact that blood can leave traces, I was challenging the fact that "blood is very corrosive". <o></o>
Yes, I think blood can leave traces, and so can basicaly any other junk that can be deposited on a weapon. <o></o>
Bird crap is one example of something that could be deposited on a weapon, and that is very corrosive because it contains an acid, uric acid I believe.

Actualy, I would have to check this out, but sweat and blood are quite similar in composition (minus the red blood cells of course). With sweat evaporating, but leaving its salt deposited on the skin, sweat may end up having a higher concentration of salt and other substances in it then blood.<o></o>
<o></o>
<o></o>
JL<o></o>

[Tobysauer]

Blood Marks

In my opinion the blood stain corrosion theory is plausible due to the salt content of blood, salt being hygroscopic (draws moisture from the air) meaning that the blood with its salt content would attract moisture for some time long after it was dry (salt+moisture+air =rust) This is an interesting thread which is making me look at the stains/pitting on the guns in my collection in a different way !!!