Summary: This article shows how to clean brass inside and out using small stainless steel pins from STM, Stainless Tumbling Media. This does not harm the cartridge brass and the results are excellent. A water-tight, rotary tumbler is required along with the stainless media.
I have been reloading for ten years. In that time, I have cleaned many, many, pieces of brass. The method I used for brass cleaning is familiar to many reloaders. I had a vibratory tumbler that I used with ground corn cob or walnut media. There were many days where I would leave the brass cleaning tumbler on for 8 hours to get my brass clean, or at least smooth. I had grown accustomed to my brass, even after 8 hours, being smooth on the outside but dirty inside. Plus, if the brass was tarnished at all, the corn cob media, even the green-treated stuff, would not bring back the luster to the brass after cleaning. Basically, if I wanted pretty shiny brass, I had to start with pretty shiny brass. I simply accepted that the inside would never be clean.
Trying Something New
Recently, while visiting AccurateShooter.com on the web, I saw an ad for Stainless Tumbling Media (STM). I visited the STM website, www.stainlesstumblingmedia.com, and was impressed with the before and after pictures. I had just finished cleaning some range brass and had used up the last of my corncob. As usual, the corncob had not done a great job. The brass was clean on the outside and dirty on the inside. Plus, any cases that were tarnished were smooth but still tarnished.
I decided to give to give the stainless media a shot. It would require an investment, not only in media ($49.99 for 5 lbs.), but a new rotary tumbler ($179.99). The stainless media does not work in conventional vibratory tumblers. But I figured, “What have I got to lose? The rotary tumbler probably works better than my vibratory tumbler, and if it really sucks, I can ask for my money back!” Also the web site said the stainless media “does not work harden, or damage your brass in any way” and the little pins will not remove any measurable amount of metal.
I called Cory, STM’s owner, the next day and purchased a Thumblers Rotary Tumbler, 5 lbs. of media and the deluxe separator. Everything arrived a few days later. I opened the box and set it all up.
Impressions of Hardware and Media
The Thumler’s Tumbler is a very stout, well-built piece of equipment. It only took minutes to set up. The paint is hardy and thick.The parts are all simple and strong. It should last a very long time. I should note that if the motor ever does die, it takes all of a minute or two to swap in a new one.
The interior of the tumbler is a thick rubber liner. The metal lid has a thick rubber liner too. The rubber does two things. First, it does the obvious, it seals the unit. Its second function was not as obvious, it cuts the noise. This tumbler is much quieter than my old vibratory unit was. You can hardly hear the tumbler, or the shells inside, tumbling away.
The media comes in a surprisingly small pack. Five pounds of stainless pins doesn't take up a lot of room. I was used to having big jugs of corn cob around for the last ten years.
Tumbling Procedure with Water and Stainless Steel Media
1. Setting up the Thumler’s Tumbler takes about 10 minutes. It comes mostly assembled, so no engineering skills are required, but you should read the instructions. There isn’t a lot to do, but there are a few important set-up details you shouldn’t overlook.
2. Pour the media in the tumbler, add brass, add 1 gallon of water, a small amount of liquid soap and a little bit of Lemi-Shine. Watch Cory’s video below for the amounts of soap and Lemi-Shine.
Do you have to use Lemi-Shine? Cory says: "Not necessarily. Lemi-Shine is the key to get your brass shiny. If you don’t care too much about the shine, then no. It can also help soften the water, which allows the soap to work a little better."
How much brass should you add? Cory suggests putting about two pounds of brass in the Thumbler’s Tumbler, which has a 15-lb overall capacity (including water). Here is how that works out for different cartridge types (small to large).
3. Shut the lid tight and start tumbling. Cory recommends one to four hours of continuous tumbling depending on the condition of the brass. After you’ve done a few batches you can figure out how long it will take for your brass.
4. After tumbling the brass, drain as much of the used, dirty water as possible out of the drum without losing any brass or pins.
5. Next, separate the brass from the steel media, and then rinse off the brass with warm water. (The rinsing stage is important to avoid spots on your now shiny brass).
6. As the final stage, dump the brass on a towel and let it dry.
SAFETY TIP: For safety's sake, always carefully inspect your brass after tumbling to ensure there are no left-over stainless pins inside any cases. Normally all the pins will drop right out, but in the very rare instance, a pin can wedge in a small-caliber rifle cartridge neck. If that happens just take a small dowel (a chopstick works well), and dislodge the pin.