Corrosion Resistance

When it comes to finishes on metal parts of guns or metals out of which firearms can be manufactured, there are none that are corrosion proof. The key words in any description of finishes applied to the metal that firearms are manufactured from are corrosion resistance. The ability of a finish applied to a metal surface to resist wear and corrosion is dependent on its hardness, thickness of the deposit, and the inherent characteristics of the element or alloy being deposited.

There are several challenges faced by the refinisher of firearms. As the president of Accurate Plating & Weaponry, Inc. (APWCogan. com, I’ll describe how we tackle them. The photos area tour of our facility. The first challenge is applying a deposit to the base metal that exhibits all the aforementioned properties and does not have to be applied at a thickness level that creates function problems due to the normally tight tolerances in quality firearms manufacturing.

In addition has a 5,000 square feet facility with 300 acres set up as a full shooting range complex. to being utilitarian, most firearms owners want their weapon to be aesthetically pleasing. The final challenge is maintaining a cost, which will be affordable with a blend of all the qualities mentioned above. While many people think that a firearm refinisher simply dips the parts in the tank and the job is done, this is decidedly not the case. The firearm must be disassembled prior to plat- Far

ing and fully reassembled and checked for functional correctness after plating. The art of polishing firearms is probably the most complicated aspect of producing a quality final product at every level of work in the industry. While there are machines that will produce flat, even surfaces and uniform round surfaces, so far only human beings are capable of producing refined finishing work on a consistent basis. The ability to find people who are interested in working in this field is dwindling.

This is why you see more and more manufacturers and custom gunsmiths turning to dull, black finishes of one type or another. This eliminates the need for skilled craftsmen. Technology is available to almost eliminate the need for human beings in the processes where polymers, Parkerizing, or black oxides are used as the final finish. Plating solutions formulated for application in the firearms industry should duplicate the finish applied to the base metal prior to plating.

If a bright master polish is ordered, the base metal is brightly polished to get the bright finish out of the tanks. If a dull finish is ordered, plating is applied to a bead blasted finish surface after flaws are removed. If flaws are left in the base metal, they will be visible and apparent in the final finish even if a bead blasted finish is applied. The lighter the color of the plated deposit, the more apparent the flaws will be in the final finish.

Chrome is one of the hardest metals that can be deposited in firearms. When dealing with steels or stainless steel, chrome can be deposited to the base metal directly. These deposits exhibit a hardness factor of 65-70 RC. The thickness of the deposit will average approximately 0.0005 to 0.001. The corrosion resistance of chrome is similar to most other plated elements about 40-50 salt spray hours with a 0.0005 thick deposit.

Chrome has above average salt spray and chemical resistance to corrosion from certain types of acids and alkalis as are all other plated deposits. Chrome does not tarnish unless it is exposed to a chemical agent that is actually attacking it. When this happens, you will see a definite change in the color, or the finish or surface rust will become visible. Electrolytic nickel has a salt spray resistant comparable to chrome but Far

only 60% of the hardness factor of chrome (45 RC on the Rockwell C scale). Application can be at thickness levels that allow for reliable functioning of the firearm, excellent rust resistance, and wear resistance greater than the hardness of the base metal. However, all nickel finishes are susceptible to discoloration from oils, solvents, contact with human sweat, and normal exposure to the atmosphere. Cerakote polymer finishes are essentially paints. Their application to the metal is accomplished with spray guns.

Cerakote is a ceramic-based coating which gives it superior wear and corrosion resistance. It creates a hard surface that resists scratching and other abrasion, such as if the pistol is dropped or otherwise impacted by something. Cerakote is a ceramic, polymer-based proprietary coating that offers industry leading durability, hardness, scratch resistance, corrosion resistance, flexibility, heat, and chemical resistance.

The basic problem with polymer finishes is getting a thick enough deposit on the wear areas of the firearm without getting too much build up in the areas where the moving parts function. Too much build up in these areas will cause malfunctions. Bluing is still a popular finish on steel firearms. Bluing does not have good wear or corrosion resistance compared to plated or polymer finishes.

However, it is traditional and can be accomplished on many levels of surface prep from dull matte bead blast to master polish bumper bright. Any of these finishing services are valuable additions to your gunsmith service offerings. We do them all. AG