INTRO
Decided to share some of my experience doing multiple bluing jobs on my own firearms.
It seems that there is no one thread here explaining process in detail start to finish. At leas I wasn't able to find on when I needed it.
While info on the Internet is available it's mostly sparse, incomplete or lacks details. Below is what I've learned and discovered over the course of two years throughpersonal experience and available publications.
And I'm ready to share those valuable tips that only come to you through trial and error experience with my fellows hobbyists.
Introduction to chemical metal refinishing
Phosphating (a.k.a. parkerizing) and bluing are both chemical passivation proccesses aimed at protecting steel against corrosion/oxidation and improving it's visual and (in certain cases) mechanical properties. Phosphating (or parkerizing) is relatively new technology, while bluing has been around for some time in one form or another.
Bluing - Black Iron Oxide
Iron oxide black (a.k.a. gun blue, bluing or 'blueing') is a conversion coating proccess. Meanning - iron in the surface layer of steel is converted to black iron oxide, also know as magnetite. Since magnetite occupies same volume as metallic iron there are no changes in part's dimmension. This is also why there is no destructive 'flaking/scaling' effect as with red iron oxide known as common red/orange rust. Bluing is accomplished by oxidation (or controlled rusting) by meanse of caustic bluing solution. No additional metall is added in this proccess, just converted what's already there into a diferent chemical form. In the sence it's same proccess that protects aluminum from oxidation - thin oxide film formed on the surface of the metal. With aliminium it happens on contact with air and in case of steel takes some caustics.
Parkerizing - Zinc or Manganese Phoshate
Phosphating (a.k.a. Parkerizing), on other hand, is a deposition coating proccess. Meanning - additional material is deposited via chemical reaction onto surface of the part, therefore somewhat increasing dimmensions of the part itself. Phosphating is done by emmersing part into solution of phosphoric acid, zinc and/or manganese with addition of some nitrates, chlorates, copper. When steel goes in contact with the solution chemical reaction takes place on the surface of the part and at this time manganese and/or zinc released out of the solution and deposited onto the surface of the steel. Some might notice that this proccess is simmilar to chrome/nickel plating, although acomplished without help of electric current.
Decided to share some of my experience doing multiple bluing jobs on my own firearms.
It seems that there is no one thread here explaining process in detail start to finish. At leas I wasn't able to find on when I needed it.
While info on the Internet is available it's mostly sparse, incomplete or lacks details. Below is what I've learned and discovered over the course of two years throughpersonal experience and available publications.
And I'm ready to share those valuable tips that only come to you through trial and error experience with my fellows hobbyists.
Introduction to chemical metal refinishing
Phosphating (a.k.a. parkerizing) and bluing are both chemical passivation proccesses aimed at protecting steel against corrosion/oxidation and improving it's visual and (in certain cases) mechanical properties. Phosphating (or parkerizing) is relatively new technology, while bluing has been around for some time in one form or another.
Bluing - Black Iron Oxide
Iron oxide black (a.k.a. gun blue, bluing or 'blueing') is a conversion coating proccess. Meanning - iron in the surface layer of steel is converted to black iron oxide, also know as magnetite. Since magnetite occupies same volume as metallic iron there are no changes in part's dimmension. This is also why there is no destructive 'flaking/scaling' effect as with red iron oxide known as common red/orange rust. Bluing is accomplished by oxidation (or controlled rusting) by meanse of caustic bluing solution. No additional metall is added in this proccess, just converted what's already there into a diferent chemical form. In the sence it's same proccess that protects aluminum from oxidation - thin oxide film formed on the surface of the metal. With aliminium it happens on contact with air and in case of steel takes some caustics.
Parkerizing - Zinc or Manganese Phoshate
Phosphating (a.k.a. Parkerizing), on other hand, is a deposition coating proccess. Meanning - additional material is deposited via chemical reaction onto surface of the part, therefore somewhat increasing dimmensions of the part itself. Phosphating is done by emmersing part into solution of phosphoric acid, zinc and/or manganese with addition of some nitrates, chlorates, copper. When steel goes in contact with the solution chemical reaction takes place on the surface of the part and at this time manganese and/or zinc released out of the solution and deposited onto the surface of the steel. Some might notice that this proccess is simmilar to chrome/nickel plating, although acomplished without help of electric current.
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