Does bluing dull over time?

[terraformer]

Just as the title suggests, I was curious if bluing dulls over time. So your gun may be shiny and blingy today but 30+ years from now, would it be duller?

Answers like "who cares, it's a gun" and "you have better things to worry about" miss the point. I am not worried. I know it's a gun, I just want to know more about the properties of bluing and how it changes over time. I know some pre-WWII era 1911s have turned rust brown while other WW1 era 1911s are dark black and dull. It's odd how different guns, presumably similar construction changed differently over time. I do know that the bluing in those two runs was different, so that is also sort of a question. Why would one bluing turn rust color while another be black and dull (and did it start out dull)?

 

[MisterHappy]

Depends.

What's being done with the gun?

If it's in a box, nice and untouched, in a humidity-controlled environment, likely not much.

If it's being handled, or used, since it's a very thin coating of, essentially, rust, it will wear mechanically, not to mention be "attacked" by oils and salts in the hand, etc.

Also, since the coating is caused by a chemical reaction, if there's a difference in the chemicals in the initail bath between manufacturers or production runs, there is a likelihood that there will be a difference in appearance down the road.

 

[Tim94gt]

I think it has more to do with how the gun is stored. I have a few older guns, some were my Fathers and others were my Uncles. My Uncle took much better care of his guns and the bluing is almost perfect still(over 40 years old) The ones from my Father were not so good. Some had rusted others dulled. He had them in closets, the attic, basement and in insulation. They were all over the place and each one suffered a little differently.

 

[cekim]

Why would one bluing turn rust color while another be black and dull (and did it start out dull)?

From the stand point of chemistry because of the process used. It is a controlled oxidation of the surface of the metal. This oxidation is started and then halted. The exact progression of the surface from Iron to Iron oxide is imperfect. Depending on the depth of oxidation and the chemcial concentrations and temperatures at the time there will be some amount of "defect density" of the desired Iron oxide.

Not only that, you have exposure over time to oils and moisture...

Red is rust, brown is rust (Fe2O3). I suspect you are seeing the color of those Iron atoms which were not sufficiently protected from the elements by the hardened outer layer. Getting darker black would imply a deeper oxidation IIRC - i.e. more atoms at the surface oxidized. Again, its a chemical reaction that is started and then stopped via temperature and soaking in stabilizing solutions, so the depth/reaction is variable.

Shine is generally more a function of surface preparation (and/or application of lacquer).