Gunsmithing Cleaning With Ammonium Hydroxide

[FrankieJames7]

so, i removed the copper from my barrel with a self diluted ammonium hydroxide solution. only about 4 patches were colored blue, and i didn't see very much copper before i cleaned anyways. i was just curious, what is the reaction between iron and nh3 or ammonium hydroxide? i cant see aqueous ammonia "etching" steel away, does it really have a chemical reaction with steel, or does it set it up to rust from just the air

 

[Gene Poole]

In general, iron and iron alloys (steel, stainless, etc) are not affected by the ammonium ion directly. The "hydroxide" part of ammonium hydroxide is water though and with the elevated pH of the ammonium solution, normal water oxidation of iron will be enhanced. Followup with several patches of a good gun cleaning oil to remove any moisture and you should be fine. Better yet, just use Hoppes #9. It has the ammonium ion in an oil-based complex and there is no water to worry about.

 

[NukeMMC]

Please read:
http://schuemann.com/Portals/0/Docum...l_Cleaning.pdf
and
http://benchrest.com/archive/index.php/t-59293.html

Highpower and long range rifle shooters have, for years, been very shy at using ammonia-based copper solvents more than sparingly in their bores, especially chrome-moly (4140) barrels. The effects of pitting are widely known and folks like Jim Borden (long-time M.E. at a HUGE tissue mill in NEPA that uses caustic solutions to break down pulp carried inside stainless piping and National Benchrest champion and gunsmith) is one of the most vocal against its use in 416R barrels. Most folks do not realize that 416R, though called "stainless" has nowhere near the corrosion resistance as austenitic (300-series). 304 or even better, 316 stainless has a 16+% Chromium content and a 10% Nickel content. 416 has 12% Chromium and 0 Nickel. The austenitic stainless typically has .03-.05% Carbon, the 416 has .15% Carbon. The Carbon defects are where the corrosion pittings start. 4140 has about .35% Carbon and about 1% Chromium.

My experience goes back to seeing 416R barrels on NM M14s after a couple strings of prone rapid in a drenching rain at Dam Neck. They all had rust on the external surfaces. YES, "STAINLESS" BARRELS WILL SUFFER FROM CORROSION.

From all this I learned to sparingly use weak ammonia-based solvents like Bore-Tech eliminator and only when cleaning copper. I then follow it with my carbon cleaner (GM Top Engine cleaner) to "normalize" the bore and minimize unwanted basic-induced effects in my bores.

 

[northern50]

I've been using 28% ammonia with a drop or two of dish soap for years, will never change either. No negative effects on barrels. I always use a liberal washing of alcohol after copper removal, then kroil, then a dry patch.