This Horse is Just About Done For
Early on in this thread, some of us (OK, I was the only one) were intrigued by the idea of the acidity of preservative waxes. I think this was brought about by the Renaissance Wax product information indicating that Ren Wax is neutral and implying that this is good and that other waxes can’t make this claim. I postulated that acid waxes applied as preservatives to firearm surfaces might in contact with condensed moisture release this acidity and thus contribute to a corrosion reaction. I also postulated that, although I was not familiar with a test for acidity of waxes, a useful test might consist of a water extraction of a wax sample, followed by measurement of acidity of the water extract.
DWalt pretty much put this idea to rest, noting that the waxes are insoluble, thus the concept of the importance of their acidity as I was describing it was not valid. Point taken.
Still, I wondered about the meaning and importance of the acidity term described in the Ren Wax brochure. I was intrigued enough to do some Internet searching (remember we used to have to go to the library for this), I bought a PDF copy of ASTM D1386-10, Standard Test Method for Acid Number (Empirical) of Synthetic and Natural Waxes (it disappeared overnight from my iPhone), and I spoke via telephone with Mr. Dennis Blaine, the exclusive US agent for Renaissance Wax. This is what I learned.
First, as background, most pure waxes are chemical compounds known as esters: these are synthesized in nature in many living organisms, and in the laboratory by a reaction to remove water from a mixture of an organic acid (perhaps a long chain fatty acid) and an alcohol (perhaps a long chain fatty alcohol). The natural waxes contain mixtures of esters, organic acids, and other substances. Waxes are insoluble in water and may decompose in time to produce organic acids and other substances. The acid number of a wax, as determined by the ASTM method, involves first a solubilization of a known mass of the wax in an organic solvent mixture, followed by titration of the acid moieties with standardized potassium hydroxide solution. The method determines the free acid content of the wax. Conditions of the test are carefully chosen so as not to allow for cleavage of the ester linkage.
OK, so the acidity of a wax refers to the free organic acid content of the wax, under conditions of the ASTM test. What is the significance of this entity?
The ASTM method was not clear on the value or use of the acid number of a wax, only that it could affect its functionality. I could find nothing on the Internet stating that the acid number of a wax is important in its corrosion prevention. I have requested documentation of the importance of the acid number in this regard from Dennis Blaine and will provide this if it is germane.
So the bottom line is that the acidity of waxes refers to their organic acid content, and there is nothing in the technical literature that I was able to locate that indicates that this acidity in any way influences the ability of the waxes to provide barrier-type protection against corrosion. To quote DWalt, “any wax will be ok on any gun.”
I wanted to make this message brief, but let me pass along that one of the most interesting websites I found in this regard is that of the (German) Transport Information Service (look under corrosion protection). Two points I immediately found important: (1) the website points out that passive corrosion protection methods (this includes films presumably such as waxes) do not provide corrosion protection beyond their barrier properties, and that if these are lost, there is no further protection, whereas anti-corrosion agents provide a “very high quality protective film;” (2) when using dessicant bags to prevent corrosion, care must be taken to avoid the dessicant bags’ touching the metal to be preserved, “as the moist dessicant would promote corrosion.”
Personally, I’m going to do as manderson (post 24) suggests, and use both Eezox and a wax on my firearms in long term storage. And I’m going to make sure the little Dry Pak Mosture Absorbing Bags I’ve been using do not contact the firearms they are supposed to protect.