At JDM Gunsmithing, we do Hot Bluing, Rust Bluing and Cold Blue for touch-up. Bluing improves both the cosmetic appearance of and provides a certain level of corrosion resistance to steels by either passivation or conversion. Bluing imparts a dark blue to black color on steels. The color can be affected by the alloy of the steel, the hardness of the steel, the bluing method chosen and the salts or rusting agent used. The sheen of your bluing job is determined by the type of bluing requested and the surface preparation prior to bluing.
In our typical hot bluing operation, we use Oxynate No.7©. Oxynate No. 7© is a proprietary bluing salts solution from a national gunsmith supplier. It has become an industry standard. Oxynate No.7© will impart a very dark, lustrous blue finish to your firearm. Stainless steel will not blue with this product. Again the sheen will be based upon the surface preparation prior to bluing. This hot bluing is a passivation process and the dimensions of the part being blued, will not change.