KRIEGHOFF quality vs. age?

wfw · 07-08-2002, 04:23 PM

Lots of thoeries, very few facts on the red/blue question.

I don't buy the theory that the metal hardness has any effect. The metal hardness comes from the crystal configuration of the metal - density of dislocations, size of crystals, has the part been work-hardened (lots of dislocations, small crystals) or annealed (fewer dislocations, larger crystals), how much of it is ferrite/austenite/pearlite/martinsite, has the carbon begun to precipitate out as graphite, etc etc etc. The finish is just a surface oxide - that is, purely chemical - effect, and the underlying crystalline structure shouldn't figure into it, as all of the crystalline formations (except the graphite precipitates, if present) are chemically identical.

I also don't buy the theory that the parts looked reddish when they came out of the bath. But here there's some indirect evidence. I have a Ruger Mk 2 with a bolt which is slowly turning red. It was definitely the normal Ruger blue when I bought it years ago, but the reddish cast is now unmistakeable. However, the change is so slow that I doubt any of us will live long enoough to see exactly how reddish it finally ends up.

Of course this doesn't prove that all reddening is a function of elapsed time, as there could be more than one mechanism for this color change. That is, Lugers and Rugers may have different reasons for going red.

07-08-2002, 04:23 PM	#11
wfw New User Join Date: Jun 2002 Location: Framingham, MA Posts: 2 Thanks: 0 Thanked 1 Time in 1 Post	Lots of thoeries, very few facts on the red/blue question. I don't buy the theory that the metal hardness has any effect. The metal hardness comes from the crystal configuration of the metal - density of dislocations, size of crystals, has the part been work-hardened (lots of dislocations, small crystals) or annealed (fewer dislocations, larger crystals), how much of it is ferrite/austenite/pearlite/martinsite, has the carbon begun to precipitate out as graphite, etc etc etc. The finish is just a surface oxide - that is, purely chemical - effect, and the underlying crystalline structure shouldn't figure into it, as all of the crystalline formations (except the graphite precipitates, if present) are chemically identical. I also don't buy the theory that the parts looked reddish when they came out of the bath. But here there's some indirect evidence. I have a Ruger Mk 2 with a bolt which is slowly turning red. It was definitely the normal Ruger blue when I bought it years ago, but the reddish cast is now unmistakeable. However, the change is so slow that I doubt any of us will live long enoough to see exactly how reddish it finally ends up. Of course this doesn't prove that all reddening is a function of elapsed time, as there could be more than one mechanism for this color change. That is, Lugers and Rugers may have different reasons for going red.