1920 .30 cal DWM Luger?

DonVoigt · 10-02-2017, 04:19 PM

Dave,
I think you meant to say "rust " bluing (not salt bluing) = blue tinge.

Salt blue(hot) and hot blue(black oxide) are the same process using melted "salts" - mostly NaOH and Nitrates. It is done at a temperature well above that of boiling water, due to the higher boiling point of the melted salts.

Rust blue uses a relatively dilute solution of nitric acid with "additives" and requires development of a rust layer which is carded away and the solution re-applied, perhaps 4 or 6 or even more times to achieve the desired finish.

10-02-2017, 04:19 PM	#16
DonVoigt User Join Date: Apr 2015 Location: near Charlotte NC Posts: 4,681 Thanks: 1,443 Thanked 4,356 Times in 2,041 Posts	Dave, I think you meant to say "rust " bluing (not salt bluing) = blue tinge. Salt blue(hot) and hot blue(black oxide) are the same process using melted "salts" - mostly NaOH and Nitrates. It is done at a temperature well above that of boiling water, due to the higher boiling point of the melted salts. Rust blue uses a relatively dilute solution of nitric acid with "additives" and requires development of a rust layer which is carded away and the solution re-applied, perhaps 4 or 6 or even more times to achieve the desired finish. __________________ 03man(Don Voigt); Luger student and collector. Looking for DWM side plate: 69 ; Dreyse 1907 pistol K.S. Gendarmerie