Cleaning brass, the good, the bad, and the ugly – my tips for great reloadable brass
Category : Reloading
One of the most common questions I get during my reloading classes relates to the need for cleaning brass prior to the reloading.
“Do I really need to clean the brass?”
The answer is always YES! And, here’s why. When you fire cartridges at the range, and the brass hits the ground (or even if you have one of those nifty brass catcher things attached to your semi auto rifle), it has the strong potential to pick up small granules of sand and grit. That sand and grit is much harder than the tool steel that your reloading dies are made from. If you don’t clean those abrasives from your brass, the grit will no doubt SCRATCH the dies. And, the dies, once scratched, will forever TRANSFER those scratches to every piece of brass that the die comes in contact with. In other words, any brief moment of laziness will result in ruined dies. So, the purpose in cleaning the brass is to really remove the potential for die damage.
The second question then arises, “How clean do I have to make the brass?” The fast answer is, “Just clean enough so that the grit is gone from the brass.”. Don’t confuse clean with POLISHED. It’s possible to have clean brass that is somewhat dull visually. However, it’s also possible to make your brass as clean AND POLISHED as you might like. So, that’s the purpose of this discussion.
Three ways to clean brass
1) The Vibratory Tumbler
The common and easiest way to clean brass is with the use of dry media, and a vibratory tumbler type brass system.
Let’s first talk about the vibratory tumbler. These tumblers are plastic bowls, supported on springs, and have an activation system that consists of a spinning motor, which has an offset weight attached to it’s arbor. That offset weight is what causes the orbital vibration.
The orbiting vibration can cause a short life issue for the motor in the cheap tumblers. In the cheap versions, the arbor (axle) of the motor spins in a bronze bushing. With extended use, this bronze bushing starts to wear into an egg shape. When that happens, the spinning laminate part of the insides of the motor (rotor) will come in contact with the inner coils of the motor (stator), and the motor will just sit there and hum. The motors are never easily replaceable, and buying another tumbler is a pain. My suggestion is to buy a GOOD tumbler in the first place. The good tumblers, Dillon, for example, use roller or ball bearings for their motors, instead of the cheap bushings. They will virtually never wear out.
There are two basic types of dry media for these tumblers. Which one you choose might depend on whether you have a “nut allergy”. My preferred media is crushed walnut shells.The granules are harder than the alternative, crushed corn cobs. The two types come in fine and medium granules. Choose the medium size.
Here’s my method for perfect cleaning and polishing of brass, in record time.
1st: Prepare the dry media for polishing.
The media, by itself, will do a so-so job of cleaning and polishing the brass. However, treating the media with a couple of simple additives will make the job go faster, and will provide a better result. With the dry media in the vibratory bowl, but NO BRASS, add a couple of capfuls of NuFinish car polish. This is a non-abrasive, non alkaline synthetis polish that will coat your cleaned and polished brass with a coating that ill keep it shiny for long time. Also add a couple of “splashes” of Mineral Spirits (paint thinner). The mineral spirits will help dissolve the soot and other hard to remove residue from the brass. It will also make the media slightly damp, helping to keep the dust down. You certainly don’t want to breathe any of the dust. Turn on the tumbler with NO BRASS, and allow the two additives to mix well with the media. About 20 minutes to 1/2 hour is enough. The media should not be clumpy. There should be an aroma of mineral spirits, and the media should not look wet. Don’t add too much of the additives, and it should be fine.
2nd: Load the brass
Tumble only one brass size at a time. 9mm Lugers will nest inside .40 S&W, etc.. So, to make sure the brass gets properly cleaned, do one size at a time. Empty out the treated media from the bowl. Fill the bowl 1/2 full of brass. It doesn’t matter how big/small the bowl is. Filling it half full of brass insures that there’s enough brass to be effective. Remember that it’s not the weight of the media pressing against the brass that does the job. It’s the weight of the brass, pressing the media into the rest of the brass , that makes the job of cleaning and polishing go faster, and come out looking better. If you don’t have enough dirty brass to fill the bowl 1/2 way, use some already clean brass, and use that to achieve the 1/2 volume. Once you have the bowl loaded with brass to be cleaned, re-add the treated media in on top. Remember that the brass is hollow, and some manual shaking of the bowl will allow all the media to fit. Don’t over fill with media, however. You need to leave some room for the vortex action of the bowl, with the brass and media, to happen easily.
3rd: Tumble and enjoy the results
How long to run the tumbler will depend on your desired results. If you want clean and somewhat polished brass, an hour or so will suffice. However, if you want bright and shiny/polished brass, a couple to three hours is all it takes. By comparison, if you don’t add the two additives, and if you don’t load the bowl right, 8-10 hours of vibrating will only yield so-so results. I personally take great pride in what my loaded ammo looks like at the range. So, about three hours is what I do. Remember, the primary purpose is to only knock off the abrasive grit so that you don’t scratch the die sets. Beyond that, the look of the brass is up to you.
4th: Separate the brass from the media
In the beginning, I used to use an old spaghetti colander, with drilled out holes (you can get plastic one at the Dollar store for a buck) to separate the media from the cleaned brass. Today, I use a Dillon media separator to do that job. I found it to be the strongest and fastest way (I tested all of the other offerings on the market, and the Dillon was the best, by far. And, well worth the money) . Dillon makes two sizes, each one suited for their two sizes of vibratory tumbler/polishers. Honestly, the small separator will handle the job of either size tumbler easily, just use smaller batches. The media treatment, if done properly, should result in clean and dry brass. If you see media dust stuck to the brass, you overloaded the media with NuFinish and mineral spirits.
5th: How long will the media last?
Two factors affect the life expectancy of the media. The corn cob media breaks down into dust faster than the crushed walnut shell. So, unless you have a nut allergy, the walnut shell option is the best. Also, as the media does its job, the media will start to get contaminated with grit, and the residues from the brass. It will start to get black in color. Some on-line comments suggest that use of a “dryer sheet” will help clean the media. If you contemplate how little surface area a dryer sheet has, you will quickly understand why the dryer sheet suggestion is pure Horse Puckies. Don’t waste your time or effort. I keep adding NuFinish and mineral spirits until I’m happy with tossing out the media. It lasts a long, long, long time. However, I always keep an older batch of contaminated media on hand for what I call “Rainy Day Range Brass.” When I bring home brass that is all caked with mud, etc, I have a quick solution. First, I rinse off as much of the mud as I can, outside with a garden hose. Then, I add some NuFinish and mineral spirits to the old media, and run that nasty brass for 1/2 hour or so. That will get rid of 90+ % of the nasty muddy grit. I then swap out the old media for new, clean (treated) media, and tumble as normal. When the “clean” media is ready for retirement, it then becomes the older batch, and I put the oldest media in a sealed plastic bag, out for the trash. Most trash collection companies send everything, after sorting out glass, plastic, etc, through an incineration system. The environment is safe.
2) Ultrasonic Cleaner
Ultrasonic jewelry type cleaner machines can be used for cleaning cartridge brass. However, there are some downsides to this choice of cleaning.
First the cleaning volume on these cleaners is very small. That’s fine if you only have a few dozen pieces to clean. However, if you are working on cleaning a few thousand 9mm cases, the ultrasonic cleaner capacity is much too small for effectiveness. Secondly, many of the ultrasonic cleaners suggest the use of a cleaning liquid. Many of those cleaning agents contain alkaline agents, which will attack and weaken the zinc (sacrificial metal) component of the brass. Using plain water (most suggest the use of distilled water, an extra expense) might work, but it will take longer. Thirdly, while the surfaces (inside and out) will be factory like new clean, this is a wet process, and the brass has to get dried quickly. There won’t be any protection on the brass, and it will likely start to tarnish quickly. If you insist on using an ultrasonic cleaner, I suggest distilled water, and a quick run through the vibratory tumbler, with the treated media. That will protect the brass. It might be just as simple to avoid the cost of the ultrasonic cleaner, and just use the vibratory media cleaning system.
3) Stainless Steel Pin Tumbling
Stainless steel pins and a rotary tumbling system can be used for cleaning brass. It has advantages over the ultrasonic systems, but also has the same shortcomings of any WET system, accelerated brass oxidation after cleaning. I do clean some of my brass using a stainless steel pin tumbling system. However, because it’s a wet system, I use it in conjunction with my media vibratory system. Here are my suggestions for this cleaning system.
First, there are a few choices for the rotary pin tumblers. Harbor Freight sells a small tumbler primary used for hobby rock tumbling. In small batches, this inexpensive device can be a good savings over a larger machine. They come in single and dual drum sizes.
If you are wanting a larger capacity, then there are a couple of companies offering good quality machines. Thumbler’s Tumbler is one, although somewhat over priced by my standards. The BEST CHOICE choice, by far, is the Extreme Tumbler’s Rebel 17 model. The Rebel 17 has a great price, and uses ball bearings in the shaft supports (pillow blocks) instead of bronze bushings that you would get in the Thumbler’s. It’s quiet, and trouble free. After millions of brass cases cleaned, only the drive belt and rubber roller have had to get replaced ( less than $20, total). The unit will come with stainless steel pins, enough to handle a full load (about 15 pounds) of brass. The pins are 400 series stainless steel. While resistant to rust, they can be picked up with a magnet (a good feature when the pins tend to scatter everywhere after cleaning is done.) Other than losing some pins through use, you won’t likely need to buy any additional pins. They will last forever.
Loading the tumbler is important for efficient cleaning. I load the tumbler about 2/3 to 3/4 full of brass. I add in a small amount (about 1 teaspoon) of citric acid (Lemishine or equivalent. I have a lemon tree in my back yard, and if I’m out of Lemishine, I add the juice of 1/2 lemon). And, also I add a couple of drops of Dawn brand dish detergent. For some reason, the Dawn brand works best, and you really only need a couple of drops. Then, add plain tap water, but do not fill to the top. You want the brass to TUMBLE and not float around in the drum. That requires that you leave some room for the brass to move freely. Even the toughest dirty brass will come out factory clean after about an hour in the stainless steel pin tumbling system. Rinse completely with clean tap water (I use my Dillon media separator and the sink sprayer) to remove all trace of soap and citric acid. The next step is very important to success.
DRY the brass thoroughly. I had tried everything, including setting the brass out in the driveway under the hot summer sun. That wasn’t effective at all. And, worse when it’s winter time. The best solution for dry brass was the use of an inexpensive food dehydrator. Place the brass in single layers on the trays, and set the heat control for the highest setting. In about an hour, the brass will be “bone dry”. Needless to say, do not use this dehydrator, after drying brass, for any food processing. Once dry, the brass then goes through my media tumbler system, to get the coating of Nu Finish on the brass. Because of the extra steps involved, I only clean the fussiest of brass this way. It has enough volume capacity to make it efficient for shooting volumes.
So, cleaning your reloading brass is a matter of volumes, budget, and efficiency. The best choice, normally, is the media type vibratory tumbling. The purpose is to remove the grit that can damage the reloading dies.