Bluing and Parkerizing
Bluing is a chemical process commonly referred to as "hot dip" that is applied to all of the parts of your gun, or golf clubs, decorative swords or knives.
Bluing consists of a multi-stage process wherein the oxidation or rust is removed with chemicals. After the removal the etched surface is removed by polishing with felt and cotton wheels. Extreme care is taken to preserve and protect the engraving and proof marks.
Depending on the final grit used, this depicts the final finish or luster.
Example: A 400 grit final polish is the approximate grit of a factory finish. To proceed above a 400 grit results in a very reflective, high luster blue. These are custom finishes and is only achievable after many hours or hand polishing.
The multi stage process consists of five stages:
A hot degreaser tank followed by rinse.
A mechanical scrubbing.
Back into the hot degreaser tank.
A final clean water rinse.
Bath with molten bluing at approximately 295 degrees.
After these stages to parts are sprayed and cleaned with large quantities of water. The parts are then quenched in water displacing oil. The items are left untouched for 24 hours. After that time the parts are ready for re-assembly.
Gun Parkerizing helps protect a steel surface from corrosion and increases its resistance to nicks and scratches by the submersion of the steel parts into a phosphoric acid solution. The process is also known as bonderizing or phosphating. The key ingredient to a parkerizing solution is often zinc or manganese with the addition of copper or chlorates. The solution is then heated to 190 to 210 degrees.
During the process streams of bubbles will rise from the parts as the reaction takes place. When the conversion process is complete, the bubbles will cease. Depending on the ingredients of the metal, colors can range from light grey to black.
Parkerizing is often associated with military finishes.