Questioon Regarding Rust Blueing

cirelaw · 11-03-2021, 09:58 AM

What method was used to keep some parts from blueing? Was it pre assembly?

Doubs · 11-03-2021, 01:36 PM

As I understand it, the rust bluing was applied by hand and wiped on only the exterior surfaces. I have seen instances where a bit has dribbled into the inside but that's only been a drop or two that left a small streak.

Mac Cat · 11-03-2021, 02:38 PM

I have never seen or read anything about the Luger bluing technique.

However, I imagined that they slid the frame over a wooden jig that was shaped like the upper receiver, which would allow them to protect the parts left in white while applying the bluing agent to the rest of the frame.

Heinz · 11-03-2021, 05:08 PM

Rust blueing is a multiple step process that involves
1. cleaning and preparing the surface to be rusted. This would include polishing the metal to the desired finish level
2. Applying the rusting agent. Normally a mix of nitric and chloride salts and agents to produce the rusting. The faster acting the agent the coarser the rust and resulting finish
3. Rusting the part. Rusting can be done in air but it production environments some manner of steam cabinet id generally used. The hotter the temperature, and the higher the humidity the faster rusting process with the same comments as in 2.
4. After the rusting the part is Boiled or steamed to convert the red oxide to a darker black oxide.
5. The loose rust is "carded off" to leave the darker iron oxide on the metal. Carding almost always is done with a very fine wire wheel or wire brush. "Carding" is used in the sense that it is in wool or linen manufacuturing
6. Back to step two and repeat until the desired color is reached..

The carding step would be very difficult on interior machined surfaces. It can be done but it it awkward trying to get the loose rust off.

PS, I agree that the P08 may have been mounted on various jigs for this process. But I doubt there was a single wooden jig in the whole DWM factory.

11-03-2021, 09:58 AM	#1
cirelaw Lifer Lifetime Forum Patron Join Date: Dec 2003 Location: PORT ST LUCIE, FLORIDA Posts: 12,216 Thanks: 6,209 Thanked 4,133 Times in 2,173 Posts	Questioon Regarding Rust Blueing What method was used to keep some parts from blueing? Was it pre assembly? Attached Thumbnails

11-03-2021, 01:36 PM	#2
Doubs User Join Date: Jun 2002 Location: Byron, Georgia Posts: 1,698 Thanks: 792 Thanked 1,684 Times in 553 Posts	As I understand it, the rust bluing was applied by hand and wiped on only the exterior surfaces. I have seen instances where a bit has dribbled into the inside but that's only been a drop or two that left a small streak.

11-03-2021, 02:38 PM	#3
Mac Cat Lifer Lifetime Forum Patron Join Date: Apr 2015 Location: Austin, Texas Posts: 729 Thanks: 2,093 Thanked 608 Times in 328 Posts	I have never seen or read anything about the Luger bluing technique. However, I imagined that they slid the frame over a wooden jig that was shaped like the upper receiver, which would allow them to protect the parts left in white while applying the bluing agent to the rest of the frame.

11-03-2021, 05:08 PM	#4
Heinz User Join Date: Jun 2002 Location: Greenville SC Posts: 1,004 Thanks: 377 Thanked 410 Times in 180 Posts	Rust blueing is a multiple step process that involves 1. cleaning and preparing the surface to be rusted. This would include polishing the metal to the desired finish level 2. Applying the rusting agent. Normally a mix of nitric and chloride salts and agents to produce the rusting. The faster acting the agent the coarser the rust and resulting finish 3. Rusting the part. Rusting can be done in air but it production environments some manner of steam cabinet id generally used. The hotter the temperature, and the higher the humidity the faster rusting process with the same comments as in 2. 4. After the rusting the part is Boiled or steamed to convert the red oxide to a darker black oxide. 5. The loose rust is "carded off" to leave the darker iron oxide on the metal. Carding almost always is done with a very fine wire wheel or wire brush. "Carding" is used in the sense that it is in wool or linen manufacuturing 6. Back to step two and repeat until the desired color is reached.. The carding step would be very difficult on interior machined surfaces. It can be done but it it awkward trying to get the loose rust off. PS, I agree that the P08 may have been mounted on various jigs for this process. But I doubt there was a single wooden jig in the whole DWM factory.