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ithacaartist · 02-21-2012, 01:09 PM

Eric,
The marks on a Luger are applied after the gun and its parts are finished, if I am not mistaken. What happens, whether the marks are stamped by hitting a marking die with a hammer to drive its harder tip into the pistol's somewhat softer steel, or rolled on with a lot of pressure, is that the the pistol's steel is displaced by this action. Iron and steel's molecules structural arrangements are changed by this physical influence--basically when the mark is struck or rolled on, the pistol's material is mooshed out of the way by the harder material of the die's face. During this trip, the molecular alignment of the steel (its "grain") is changed in the area affected.
I think what we're seeing in the halos is the different ways the pistol's steel behaves over time. You may have noticed postings about variations in the appearance of rust bluing among all the parts of the Luger--some turn plum color, some are blacker or bluer than their surrounding parts buddies. This varies by hardness and by specific alloy. Lets not worry about differences created by temperature, formulation, and duration of the bluing process, which I think is not relevant here.
Since we've changed the hardness of the area hit, it will behave differently from the same material around it which has not been whomped with a die, when exposed to the air and other elements over time. I'm thinking that there is another aspect that makes the steel around a stamping behave differently. Imagine painting an empty balloon, and blowing it up after the paint has dried. The paint will crack and slough off the surface as the balloon grows. My thought is that, other than changing the grain alignment, the displacement of surrounding material may work in the same way: The top coating of (literally) rust on a blued surface is not very flexible, and I think some of it will be found to have been lost during this movement. At the very least, the die strike will move the struck material is a way that swells the steel around the mark; but it does not move the top coating to cover this swollen area in the same way it is covered when left untouched, thereby leaving thinner rust bluing around the stamped figure. In turn, this exposes the white steel beneath as the rust blue is stretched thin and more translucent.
A halo happens after first stamping the mark, then waiting several decades for the effect to fully establish itself via ambient corrosive elements of the environment in which the gun spends that time. You can't re-stamp a refinished gun and get anything like this effect because 1) you won't be moving virgin, freshly finished material of original hardness--its temper was already changed the first time and 2) it takes time to enhance the effect.

I don't know if forgers can duplicate the halo effect on a gun. It may be possible chemically.

David Parker

02-21-2012, 01:09 PM	#2
ithacaartist Twice a Lifer Lifetime Forum Patron Join Date: Mar 2011 Location: Atop the highest hill in Schuyler County NY Posts: 3,374 Thanks: 7,447 Thanked 2,613 Times in 1,380 Posts	Eric, The marks on a Luger are applied after the gun and its parts are finished, if I am not mistaken. What happens, whether the marks are stamped by hitting a marking die with a hammer to drive its harder tip into the pistol's somewhat softer steel, or rolled on with a lot of pressure, is that the the pistol's steel is displaced by this action. Iron and steel's molecules structural arrangements are changed by this physical influence--basically when the mark is struck or rolled on, the pistol's material is mooshed out of the way by the harder material of the die's face. During this trip, the molecular alignment of the steel (its "grain") is changed in the area affected. I think what we're seeing in the halos is the different ways the pistol's steel behaves over time. You may have noticed postings about variations in the appearance of rust bluing among all the parts of the Luger--some turn plum color, some are blacker or bluer than their surrounding parts buddies. This varies by hardness and by specific alloy. Lets not worry about differences created by temperature, formulation, and duration of the bluing process, which I think is not relevant here. Since we've changed the hardness of the area hit, it will behave differently from the same material around it which has not been whomped with a die, when exposed to the air and other elements over time. I'm thinking that there is another aspect that makes the steel around a stamping behave differently. Imagine painting an empty balloon, and blowing it up after the paint has dried. The paint will crack and slough off the surface as the balloon grows. My thought is that, other than changing the grain alignment, the displacement of surrounding material may work in the same way: The top coating of (literally) rust on a blued surface is not very flexible, and I think some of it will be found to have been lost during this movement. At the very least, the die strike will move the struck material is a way that swells the steel around the mark; but it does not move the top coating to cover this swollen area in the same way it is covered when left untouched, thereby leaving thinner rust bluing around the stamped figure. In turn, this exposes the white steel beneath as the rust blue is stretched thin and more translucent. A halo happens after first stamping the mark, then waiting several decades for the effect to fully establish itself via ambient corrosive elements of the environment in which the gun spends that time. You can't re-stamp a refinished gun and get anything like this effect because 1) you won't be moving virgin, freshly finished material of original hardness--its temper was already changed the first time and 2) it takes time to enhance the effect. I don't know if forgers can duplicate the halo effect on a gun. It may be possible chemically. David Parker