Totally tarnished brass.

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mrawesome22

New member
I got my metal detector out yesterday and found 70 pieces of .40S&W brass that had been laying on the ground for about 5 months.

This stuff was black, super dark brown, whatever you want to call it. Tiny insects had made some of them their home.

So I tossed it in the tumbler last night and wake up to the brass being ultra clean, but still the same color.

Is this some chemical reaction between brass and H2o that turns it brown and can't be corrected unless a substantial amount of surface metal is removed from the brass first?

I'm hoping someone has a chemical explanation for this.
 
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Peter M. Eick

New member
I am not a chemist, but if you consider the rain as being slightly acidic (you know "acid rain") and then the ground conditions can be reducing if more organic or oxidizing if more sandy you can easily see that the brass may have been chemically etched.

I have had poor luck with brass like that when it comes to reloading. I would probably recycle because it is high pressure stuff like 40 vs. say 38 special.

Is 70 pieces really worth it?
 
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Unclenick

Staff
You either just have a very thick oxide layer on the brass, or you have picked up some steel cases. In the latter case, test with a magnet. In the former case, soil composition may indeed play a role in this. You can likely remove it with the Iosso or Lyman liquid brass cleaners, if you really want to try. Just don't use an ammoniated polish for the soak. It will weaken the brass.

You didn't say what you tumbled it with? Did your media have a polish in it, or was it just plain corncob or walnut? You might find a more aggressive medium, like the green Lyman corncob, would have cleaned it?

Unfortunately, if the soil or length of stay were really significant, once cleaned, you may find pitting in the brass. As Mr. Eick says, such cases will not be as safe in a higher pressure round as they would be with black powder level pressures. I would be inclined only to put mild target loads in them, if your gun will function with such loads?
 
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mrawesome22

New member
These are not steel cases. I refuse to shoot steel cased ammo in any of my guns. They were tumbled in plain walnut (lizard litter) with no polish. I'm gonna get some polish and see what that does.

Thanks guys.
 
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Namerifrats

New member
Theres nothing wrong with shooting steel cased ammo. Also, for just 70 peices of 40 S&W, I'd just throw it away because the brass plentiful at most any range. I picked up 700+ peices of 40 S&W last weekend at my local range.
 
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Linear Thinker

New member
Awesome - brass is non-magnetic.
How did you find it with your metal detector?
Mind you, I don't know much about metal detectors, but I am curious.
LT
 
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donttellthewife

New member
For the worst looking brass I have had some luck doing this. Add Nu Finsh car polish to walnut media and let it run awhile before adding the following. Stick chrome polish ( the type you would use for a cloth buffing wheel, it's white ) I use a cheese grater to make some powder out of it then add that to the media. It worked well for some tarnished brass I had. Another thing that may help is concentrated lemon juice and dawn liquid dish soap let it soak over night in that. Try this site as well http://www.frfrogspad.com/homemade.htm
 
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mrawesome22

New member
Awesome - brass is non-magnetic.
How did you find it with your metal detector?
Mind you, I don't know much about metal detectors, but I am curious.
LT
Click to expand...

http://electronics.howstuffworks.com/metal-detector.htm This link will give you information on how metal detectors work.

Metal detectors will find any kind of metal. Magnetic or not. Aluminum is non-magnetic, but when you first start to use one, you will find many, many, many aluminum cans and old pop tops.

To find brass, just go to a place where you know you've lost some empties and turn the sensitivity all the way up. With the sensitivity all the way up, it will detect metal that is very deep in the ground, or stuff that's right on the surface. It will also detect while you are sweeping the head very fast. So, with the sensitivity turned all the way up, you can cover a lot of ground quickly.

Now when you get a good strong beep, try to pinpoint it by sweeping the head back and forth over the beeping area. Now turn the sensitivity to half. Again, sweep until you've got it located. By now if it's still beeping strong, you know it's pretty close to the surface. Now turn the sensitivity to its lowest setting. If the object is on the surface (or an inch or so underground),
you will only get a beep when the center of the head is directly over top of it. Almost forgot, when the sensitivity is at it's lowest, you must sweep the head very slowly.

Anyway, if you are getting strong beeps with the sensitivity at its lowest and can't find anything, then it's underground and not one of your empties.

Then again it could be a gold coin from the 1600's! LOL

I beg you not to look for metal around your house as it may cause a divorce! LOL "Honey! I found the 14th piece of angle iron you were asking for! So don't break your ankle in that 1 foot hole I dug." LOL
 
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Peter M. Eick

New member
Depending on the type of metal detector, you can get different variations. Some just measure the magnetic field using a saturated flux gate (rare) and compare it too the opposite cycle of the pilot wave. I don't think this technique has been used since the 50's.

Another technique is to measure the magnetic susceptibility and/or conductivity (very common). This technique uses a coil loop that has a driven sine wave going through it. Passing a magnetically susceptible material in or around it will change the phase angle and the frequency of the resonance of an LRC circuit that can then be measured and reported back as either a tone or a number in terms of susceptibility. Conductive material will also impact this tool in a very similar way.

Thus properly done you can measure the susceptibility of the earth which would vary with magnetic material or the conductivity of the earth which would vary with metallic bodies.

If you are wondering, I did my Master's on Magnetic susceptibility as a function of Frequency and had to build a bunch of different tools to measure it. As a result I accidentally made a bunch of metal detectors before I realized my error in lab technique.
 
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TWB

New member
This solution works pretty well for bringing dark brass back.

Take 1 gallon of white vinegar, add 2 tbsp salt and 1 tbsp liquid laundry detergent.

This can be mixed up to 50/50 with hot water, if desired. I use it straight.

Pour it over the brass, and let it soak for several minutes. I like to put it in a jar with a lid and shake it up intermittently. After 10 or 15 minutes, remove the brass and wash it off with clean water. Save the sol'n, because it can be used several times....it turns blue green as it is used up.

The brass will look terrible - mottled/streaked/discolored. Throw it in your vibrator with your favorite additive....I like NuShine car polish, and when I'm using the machine outdoors, I pour in a glug or two of 70 or 91% (preferred) rubbing alcohol. Your brass will polish up like shiny brass should look. If it does not, it may have been damaged by soil chemicals or whatever.

(The alcohol puts a bright shine on brass in excess of new brass shine, and then evaporates, leaving your medium unchanged.)

I can't tell you all the reactions causing the darkening, but the copper will form sulfides that are dark, and most soils (Vidalia, Ga. being an exception) have sulfur compounds present. Oxidized copper is darker than the clean/pure metal also. (Used to work in a copper mine and smelter, and the anodes darkened in the weather without soil exposure.)

twb
 
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Powderman

New member
I found a simple and very effective solution by accident.

For cleaning and mirror polishing, I use 1/2 corncob, 1/2 walnut, and about 1/4 to 1/2 small tube of Simichrome polish.

Mix your media to get a tumbler full. Start it up, now just squeeze in the polish. Cover it up and let it run for about two hours; now it's ready.

This mix will take absolutely horrible brass and put a mirror shine on it within 3 hours, guaranteed!
 
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Ignatz

New member
I think brass laying around for months picks up a beautiful dark patina(like marbling). Some almost gets a glass like finish to it after it gets tumbled. I'm only reloading 45's and 38's at low to mid velocities. Never a problem with reloading.
 
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Unclenick

Staff
Looking at all the above suggestions, I'll mention that vinegar and salt and later detergent were all part of the old NRA liquid cleaner. The only problem I have with it is the acetic acid in the vinegar activates the brass and allows it to re-tarnish very easily. The lemon juice has citric acid in it which tends to passivate the metal, so it should not induce the tarnishing. You can also get citric acid in powder form from wine making suppliers, if you want to experiment with it without getting the sticky sugar in lemon juice involved in the process.

Nick
 
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Slamfire

New member
Yesterday I was shooting demilled US Military surplus .223 brass from 1987 or so. When I purchased the stuff, it was as brown as a hazel nut. Now that it is on its fifth reload, and sixth firing, some of the brown is worn, a bit.

I shot a 199-8X at 200 RF with the stuff, so I don't think brown is bad. Just hard to find the stuff during the brass and trash period.

I also used five time fired S&B at 300 yards, only shot a 195-7X. That stuff was shiny, so I guess brown brass shoots better than shiny brass.

My 600 yard score is proof that shiny brass won't shoot straight. Next time I am going for brown brass across the course.
 
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Trapper L

New member
I don't know why ya'll are making this difficult. Go buy some Iosso, cut it in half with water and dip them. They come out like new.
 
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mrawesome22

New member
Well I bought some Lyman's Turbo Case Cleaner and let this brown brass sit in it for 5 minutes. Then tumbled for 3 hours.

It now is the best looking brass I've seen. It's like looking into a golden mirror LOL.

+1 for Lyman's Turbo Case Cleaner!
 
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