Brasso, really?

[billcarey]

I see this thing about not using Brasso to tumble brass all over gun forums and it's always posted in a blanket statement that ammonia is harmful to brass. To date, I've yet to see anything showing Brasso's harmful ammonia concentration being backed up with lab testing, etc. After looking at MSDS sheets and such I'm curious just how serious of a problem it really is. I don't tumble with anything but dry media and can't say so from personal experience.

I did some searching and took the info from mfg sites, not forums... Alum is in brass to make it harder and pure ammonia is stated (MSDS) as "severely" corrosive to aluminum. The product in Brasso is ammonium hydroxid which is ammonia mixed with water...the highest concentration I could find (using several MSDS) is 44% ammonia and the smallest 15% ammonia...all are stated as "corrosive" (not severely corrosive) to aluminum. The concentration of ammonium hydroxide in Brasso's MSDS is 1% to 3%. Deduct the water by 65ish% and it's less than 1.5% ammonia in Brasso.

So if brass is harmed with Brasso, is that after soaking in Brasso for 10 minutes, 10 hrs or 10 yrs? It seems to me the amount of concentration is so small it most likely takes the alum stains off on the surface (like passivation does to SS) and doesn't penetrate far enough to trash the brass. I'm no expert on Brasso but from reloading over 20 yrs I know brass gets brittle without Brasso.

Does anyone have hard core info on how fast Brasso kills brass?

 

[Unclenick]

Bill,

Google season cracking or look at the Wikipedia article, here. It is good enough. All it takes is the ammonia in air from compost to weaken brass. It is the reason the military started annealing case necks, which reduces bullet grip, but also reduces the stress in the brass where the seated bullet is stretching it. If you aren't doing neck annealing regularly and are letting your case necks work-harden with each reloading cycle, then shooting the ammo before it has time to stress relieve by cracking may get around the risk. I'm not certain.

I don't know how long it takes the ammonia in a polish to attack brass deeply enough to cause a stress cracking problem? Cartridge brass is 70% copper and 30% zinc, both of which react with ammonia. The reaction with zinc produces zinc hydroxide, which is a white precipitate. The reaction with copper produces copper hydroxide which is a deep blue color, and is water soluble. You've no-doubt seen it that on patches of ammonia-based copper solvent coming out of a fouled barrel.

Like you, I can't say I know anyone who specifically traced a split neck or a head separation to the use of Brasso, but then, since those things happen eventually anyway, how would they know whether Brasso had hastened the event or not? You'd have to do an experiment starting with a hundred new cases, polish half in Brasso and half in ammonia-free polish, always fire the same loads in both batches the same number of times and see if there is a statistically significant difference in their life expectancy?

For myself, just knowing ammonia can weaken brass, I figure Murphy's law will show me everything is just fine and no problems until I'm right in the middle of winning a match or on an expensive hunt, only to discover neck cracks that mean I've got less good ammo with me than I need.

In your shoes, I would anneal any necks I had used Brasso on then stop using it. There really is no need to risk losing brass prematurely with all the other cheaper ammonia-free polishes you can buy out there. Soft scrub works, though you'll want to rinse the soap off later. You can make your own tumbler polish by buying a bag of diatomaceous earth and making a slurry of it with mineral spirits and maybe little oil to keep it from dusting. Then you don't need to concern yourself with letting the reloads sit around for a few years if it comes to that.

If you want to see ammonia's effect on brass for yourself, drop some .22 rimfire cases in a jar of ammonia and watch them dissolve. It takes weeks, IIRC, but the brass is weakened long before there is visible etching of them.

 

[Slamfire]

I have one material failure analysis book that shows an example of a brass propeller where the blade broke off due to season cracking caused by bird poop.

Some people can live with increased risk, some can't

"Conehead" took my friend Johnny for a nightime drive well over 100 mph. Johnny later examined Cone's car and found that three tires were bald and one was only being held on by two lug nuts.

I know Cone later went to the hospital due to a motorcycle wreck, don't know if he is still alive.

Risky people have a lot of accidents.

I have my limits and shooting weak brass is one of them.

If you need absolute proof, run a test. Expose a set of cases to varying levels of Brasso. Record the times and concentrations.

Then try to find someone who wants to shoot the stuff.

Do be ethical and tell that person he will be testing the rounds to destruction and that at the conclusion of the test, the tester might consider what type of medical prosthesis to use for his hand, or head.

 

[CrustyFN]

The way I look at it is there are so many good products out there that will do as good a job and you know they won't hurt the brass, so why take the chance.

 

[Mike Irwin]

That nice brass cartridge case is the only thing that keeps the Powder Pressure Gnomes from escaping from your gun and ripping off and consuming chunks of your face.

Ammonia is the Powder Pressure Gnomes' friend in that it can help them escape from their brass prison, and they have a serious hankering for some sweet face flesh.


To me, it's QUITE simple, really.

Ammonia is known brass antagonist.

That brass case is the only thing that stands between you and as much as 60,000 PSI of chamber pressure.

At the very least you could damage your rifle severely.

At worst, you could be severely injured or even killed.

A blown case head is NOT something to screw around with.

 

[wncchester]

"To date, I've yet to see anything showing Brasso's harmful ammonia concentration being backed up with lab testing, etc. After looking at MSDS sheets and such I'm curious just how serious of a problem it really is.."


There is no valid reason for using it on cases anyway, any metal polish without ammonia will do the job just as well. It isn't "Brasso", as such, that causes problems, it's the ammonia. How rapidly ammonia affects brass depends on a lot of things; the alloy, the strength of the ammonia, the temperture and the time of exposure.

Since there is no current data available and you question the validity of the information, perhaps you could do a series of tests with it and tell us much and how long Brasso can be used before experiencing a major case rupture.

 

[Bamashooter]

i have heard the same as most of you that brasso is harmful to the intergrity of the brass case. have i witnessed any issues involving said brasso, negative. i have heard enough to NOT use it to clean my cases. that kinda sux becouse brasso cleans the hell out of brass, very quickly.

 

[P5 Guy]

Ammonia & Copper

I worked in a plating shop for 5 years. In that shop an ammonia solution was used to strip copper from triple plated chrome bumpers. The old way of doing decorative chrome was the plate the base metal with copper then nickel and then chrome.
I always hated the smell of that stripper.
Copper is the major metal in the brass alloy.

 

[Ike666]

Is Dillon Case Polish just Brasso in a different container. It sure smells like its got ammonia in it and its the same Carolina Blue color.

 

[billcarey]

I'm just curious and looking for facts on the real vs imagined risk. I'm not interested in being a guinea pig for the use of Brasso either and I don't use any type of polish on my brass. Just for fun I may soak a couple shells in Brasso and do some destructive bench testing over time to see what happens.

IKE666, Dillion advertises their product not to contain ammonia.

 

[jmorris]

Dillon polish has water, petroleum solvents, silicones, silicon dioxide, abrasives, oleic acid, amine and dye, no ammonia.

 

[kgpcr]

I have used Brasso for many years with not one problem. Just a little glug in the media and you are good to go. I never knew that was a bad thing

 

[Unclenick]

Lets hope you never get the final proof that it is. It will be less of an issue in most common pistol rounds just because the pressures are lower than rifle rounds. But as a guy who likes to keep reloading .45's up until about the 50th go-around or so, I'm still going to stand clear of it.

 

[sonnycrockett]

whats a better alternative ?
I use Brasso,no probs so far but why take a chance

 

[Ole 5 hole group]

Take a little time and read this thread

http://castboolits.gunloads.com/showthread.php?t=83572

 

[F. Guffey]

Belding & Mull hand book 1955 on cleaning and pickling brass for storage and blocking oxidation, it worked and easy to identify, when finished the finish turned black.

The process started with submerging the cases in a 1% solution of sulfuric acid for a maximum of 3 to 5 minutes then rinsed, after rinsing the cases were to be rinsed again in boiling water then dried inside and out, drying? nothing has changed, they did not recommend placing the cases in the oven with the door closed. back then (again) if the case gets too hot to the touch the case is too hot.

Cleaning brass, again, for the worst of it, the cases that would require three days of tumbling I reduce the time factor to 2 hours maximum by cleaning in vinegar FOR A MAXIMUM OF 15 MINUETS, because I took the time to determine the effect 4% vinegar had on the case, in time, the vinegar will dissolve the brass case, it starts with turning the case pink etc., etc.. For the worst of cases there is nothing to be gained by soaking the case beyond 15 minutes AND I have satisfactory results with less time, so time is a factor, Cleaning with vinegar is a one time thing, with vinegar, the case does not turn black.

Tumbling: I use media and nothing.

F. Guffey

 

[44 AMP]

Safety Data

After looking at MSDS sheets and such

MSDSs are wonderful things, containing all the legally required data for worker health and safety.

However, they virtually NEVER adress product use (beyond safety) and the nice to know stuff about where it is suitable and where not. That info has to be found other places.

Always heard that Brasso was bad for your reloading cases. Good for your uniform brass, but not shooting brass.

Probably a small amount in the tumbler willl not cause significant problems (especially if cases are cleaned after, with something to neutralize residue). I think the "Brasso is bad" comes from people hand polishing cases with it, like we did for our uniform brass in the service.

 

[ZeSpectre]

Here's what I know.

A friend gave me two boxes of "new old stock" unfired .223 brass that had been sitting in his workshop since about '88. When I prepped it and started loading box "A" was fine but the other (box "B") I had cases cracking at the mouth as I sized and/or crimped them and a lot of cases in box "B" had little black spots all over that cleaned off when tumbled but left copper spots which I later learned were leeched out weak spots.

We puzzled over this for a while and then my friend remembered that box "B" was stored on a shelf right over his cat litter box (in a small closet) for many years...yup, a constant ammonia cloud.

 

[brickeyee]

Alum is in brass to make it harder

I would suggest you read a lot more.

Alum is a chemcial compound, hydrated potassium aluminum sulfate [Al(SO4)2 * 12H2O].
The class of compounds known as alums have the related stoichiometry AB(SO4)2 * 12H2O.

If you meant aluminum, it is not present in cartridge brass.

Brass is a mixture of copper and zinc (cartridge brass is 70% copper & 30% zinc).

Ammonia attacks brass with residual stress like the tension we use to hold bullets in cases.

The zinc is the main target, and lower zinc brasses are less subject to stress corrosion cracking.

With all the available things to clean and polish brass, using anything with ammonia (or ammonia compounds) is not worth the risk.

65,000 PSI 3,000 F gas in your face, and possibly metal shards from a failed case, are not pleasant.

 

[Unclenick]

ZeSpectre,

Thanks for the validation. I read soldiers would occasionally relieve themselves in the corner of the old ammo storage bunkers. Same effect on nearby ammo.


Ole 5 hole group,

Thanks for the excellent link. I've only read the first page thus far, but it matches the experience I had with putting brass in a stainless passivating solution. Unlike vinegar, which activates the surface, the citric acid does not induce after-tarnish. I'm not sure of the mechanism, though I am pretty sure it is not the same as passivating stainless steel. In that scenario, the acid etches out free iron, usually embedded by tooling or micro inclusions that didn't alloy well. The brass won't have those.

Phosphoric acid, acting on plain steel, leaves a thin iron phosphate layer behind, kind of like micro-Parkerizing, but with iron rather than zinc or molybdenum, that helps protect the metal for a short time. It's not great protection and a couple or three days is the usual limit before moisture tunnels through. There are some commercial phosphoric acid rust treatments that include enough potassium or sodium dichromate to deposit chromium oxide on the steel to inhibit rust further.

As to Citric acid on brass, since it is a chelating agent, I expect it converts the oxides on the surface to citrate complexes and some of these remain bonded to the surface. It may be better to leave your brass in this condition than to tumble it afterward. Hatcher described leaving polished and unpolished brass on the roof of a building in an area that produced chemicals and that had a very corrosive atmosphere. The unpolished brass was oxidized at the neck from flame annealing and also some during working, apparently. A year later the unpolished brass was still intact, while the polished brass had all been eaten away. That is why military brass specs insist the annealing stain be visible. They want to insurance it was not polished as commercial brass is.

What is interesting is that the action on brass is said to be self-limiting. In the case of phosphoric acid, I've seen that in Parkerizing. After a few minutes the bubbles just stop forming. I assume that's because the phosphate layer is protecting the metal at that point? The same is apparently the case with citric, from that post. I did not realize that, as I simply withdrew brass from citric acid when it looked clean. Leaving it for a time would be an interesting experiment.

I don't know whether to like vinegar or not. It clearly activates the brass surface, as it stains heavily over the next several days if not polished. But perhaps that staining adds protection a-la-Hatcher's experience? It may. The problem I have with the vinegar stained brass has simply to do with finding the stuff in the grass after firing it in a self-loader.


Re Brickyee's comments, those who are interested should go to matweb.com and search on cartridge brass. You will get a long list of different tempers to choose from, but the 70/30 composition is correct in any of the UNS C26000 brasses. The technical datasheet includes composition, density, and other properties you may or may not be interested in.