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What is that red "rust" on my brass?

Discussion in 'Handloading and Reloading' started by IMtheNRA, Nov 27, 2007.

  1. IMtheNRA

    IMtheNRA Well-Known Member

    I was reading the "clever discoveries" thread that is tacked at the top of this forum, and I came across a method of cleaning brass in a mixture of water, vinegar, salt, and laundry detergent. Tonight, I soaked a test batch of used brass in this mixture to see if it really works.

    After about 45 minutes, I rinsed it off very well and even soaked it for a few minutes in water with baking soda to minimize any residual acid from the vinegar.

    Much of the .44 brass developed red areas that look just like rust. For some reason, the Winchester brass seems to be affected the most, with other brands developing the least amount of red.

    Coincidentally, a few days ago, when I was sorting some of my own once-fired brass that I accumulated over the years, I noticed a handful of .45 cases with the same red "rust".

    Does anyone know what this red stuff is and what, if any, implication it has on case life and reuse safety?
  2. The Bushmaster

    The Bushmaster Well-Known Member

    The pinkish or redish spots on the cases are a reaction of the tarnish to the cleaning solution. After rinsing and drying, tumble them. If you don't see any pitting, reload them. By the way...45 minutes is a bit much. All you need to do is soak them for 15 to 20 minutes stirring or shaking them every few minutes. Rinse them thoroughly, dry and tumble. Baking soda? haven't seen the need for that if you rinse them well...
  3. 50 Shooter

    50 Shooter member

  4. rcmodel

    rcmodel Member in memoriam

    It's not good whatever it is.
    You often see it on range pick-ups that have laid outside for a long time.

    Once it gets a foothold, even aggressive tumbling sometimes won't remove it. The next stage is green corrosion often seen on old mil-sup ammo that will eventually weaken & ruin the cases.

    I agree with 50shooter that something sinister is taking place with the makeup of the brass alloy.

    And that's why I use a tumbler instead of water, soap, vinegar, salt, pepper, and celery salt to clean my brass.

  5. IMtheNRA

    IMtheNRA Well-Known Member

    Thanks guys, I'll toss this lot in the recycling bucket. I'll stick with dry tumbling and leave the spices in the kitchen...

    The brass did not get much cleaner, but it sure smells fresh...
  6. Jim M

    Jim M Active Member

    IMtheNRA, I agree with the previous posters that the red spots are not good -- 50 Shooter probably nailed it. The dezincification (chelation) is not only unsightly, it weakens the brass. Consider that as an early indication that your brass cleaning routine is not effective, and possibly damaging to your brass.

    The active ingredient in vinegar is acetic acid. That's not what you want to use for cleaning brass. There was a brief article in The American Rifleman more than 40 years ago that discussed their study of cleaning methods, and methods of removing tarnish from brass. They recommended citric acid. Now, the citric acid that you normally encounter is no stronger than lemon juice. It is safe to use, and will not damage your brass.

    I recently ran across a product that contains enough citric acid, and is also a good cleaning agent. It is "AJAX Lemon Liquid dish detergent." It is available at most supermarkets, and is quite cheap. One cartridge case full of the AJAX (hold your finger on the primer hole to keep it from leaking out, if you have already deprimed the brass) and fill your container up with hot water from the tap. If you don't have a tumbler that works with liquids, use a bucket and stir or shake the container every few minutes.

    Skip the laundry detergent -- the AJAX is a detergent. Also, skip the salt.

    The dish liquid is not only safe to use, it is safe to dispose of down the drain.

    If you have seriously cruddy cases (usually dried, carbonized or burned oil deposits) on your brass, it might take more drastic measures. Tri Sodium Phosphate is a good cleaner that will remove that oil deposit. It is available at hardware stores, and is very cheap. It is usually sold as a driveway cleaner. Just follow the directions on the package to mix up a batch, then let your brass sit in that for about a half hour. Again, stir or shake every few minutes.

    Some commercial reloading shops mix the Trisodium Phosphate and citric acid in one mixture and put the brass in that. Citric acid is available in the canning section of many large supermarkets (it is used in canning tomatoes). I don't like to mix them because the sodium in the Trisodium Phosphate will react with the citric acid, forming a salt and effectively diminishing the cleaning action of both. I prefer the AJAX because it is simpler to measure, and one less separate ingredient that I have to worry about.

    I only use the Trisodium Phosphate for really cruddy old brass that I get from outside sources, or range pickups. I use it just mixed in hot water. Trisodium Phosphate is a fairly common chemical that was widely used in laundry detergents in years past. Unfortunately, the phosphate is a fertilizer, and in large quantities such as happened when every housewife was using laundry detergent that contained it, it causes algal blooms in lakes where the sewage is discharged. That's the reason it is no longer used in laundry detergents. Your use of it isn't going to be enough to cause any problems, but I make it a practice to keep my usage to a minimum.

    Jim M.
    Last edited: Nov 27, 2007
  7. 50 Shooter

    50 Shooter member

  8. IMtheNRA

    IMtheNRA Well-Known Member

    This is from the Wikipedia article posted by 50 Shooter:

    It is believed that both copper and zinc dissolve simultaneously and copper precipitates back from the solution. The material remaining is a copper-rich sponge with poor mechanical properties, and color changed from yellow to red.

    Yikes! This red "rust" on the Winchester cases I asked about looks just like pure copper!!! :eek:
  9. Caimlas

    Caimlas Well-Known Member

    $10 on "zinc corrosion". Zinc does not, IIRC, react well with salts. The use of a detergent (or the specific kind of detergent) may have catalyzed a chemical reaction.

    Zinc is soluble in acid - it's something we regularly take in through food - and the addition of the surfactant (soap) may have had an impact on alloy separation - I don't know enough about alloys or surficants/acids to make a determinant answer on that. :p

    I know I would not use salt in such a mixture, if I were to ever attempt such a thing as a homemade brass cleaner.
  10. Caimlas

    Caimlas Well-Known Member

    Damn it! I somehow missed 50 shooter's post. Sorry for the duplicate response/partially-informed musing. :p
  11. The Bushmaster

    The Bushmaster Well-Known Member

    Well shoot (that's s**t with two "o"'s)...I've been cleaning extremely dirty brass with that solution for 20 years. I have not seen any deteriation of the brass over the 8 to 15 reloads or when it gets lost like in the case of 9mmX19 and .45 ACP. 15 to 20 minutes with regular stirring and a good rinse then tumble. The "pink" or "red" comes off in the tumbler. If you see any pitting, toss it, but I have taken a magnifying glass and have not seen any pitting. I will continue to use this method...
  12. 243winxb

    243winxb Well-Known Member

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