My Stainless Steel Media Thumbler Brass Case Cleaning Findings

I think there have been HUGE advances in the discussion of SS media brass cleaning.  I know my learning curve was logarithmic.  Lots of people have submitted some very good […]

4cb4909dI think there have been HUGE advances in the discussion of SS media brass cleaning.  I know my learning curve was logarithmic.  Lots of people have submitted some very good data and findings.  Really got me thinking.

There have been a lot of threads on the internet about SS media tumbling and various finding, problems, and solutions.  Here is what I have found personally.  I think this is the coolest tool for cleaning just about anything metal.  I not only use mine for brass but it works great for vintage guitar parts too!!

I have a Thumbler tumbler and I use pins I purchased from these guys.

I love my pins.  They are perfect and appear to be very high quality.  I started with 5 lbs.

My goal has been to be able to clean brass to two levels.

1.  Clean range brass for processing- This is when I load up the unit with a lot of cases.  I never really tumble long enough to damage the brass.  The cases get very clean inside and out…  especially compared to walnut or corn tumbling.

2.  Clean brass to “like new”- this includes the primer pocket being completely clean.  That lead or whatever is in that pocket from the primer is stubborn…

That’s why I started playing with the pin ratio.  The case mouth peening is real (although I am making 223 from de milled Lake City 223 right now and every mouth is peened…  yes that’s right…  they clean after trimming at Lake City…)  I am convinced the damage comes from the case on case collisions, not the pins at all…

I did add abrasive tape to my drum where the drum rides on the pads. Now I don’t have to worry about getting soap on the drum and it slipping.

I promise I will do some work and post the results.

Anyway…  This is what I found.  I use water, Dawn, and about a half a teaspoon of Lemishine.  You don’t need Lemishine but the cases come out noticeably prettier and shinier with it.  I have recently started playing with ratios of brass to pins and tumbling time based on reviews and feedback from other users on the forums.  People had complained about the necks getting peening at the mouth.  I too had witnessed this myself.  I have had it so bad on my 6Br cases it wouldn’t let the bullet seat.  That was back when I was doing long cycles with lots of brass.  Those cases had a VLD inside ream so the mouths were very thin.  I think it is far less evident on say LC cases that are cut at a 90 in trim and never really champferred.  It like makes the mouth look like a trumpet or flared.

Many theorized that the brass colliding with itself was causing the peening.  I think I am going to agree.  I think that people are trying to do too many cases at once.  I did a test recently and using my 5 lbs of pins I cleaned 50 308 cases.  I only had to tumble for about 45 minutes in my 5 lbs of pins to get the cases completely clean inside and out.  I saw no real peening that concerned me at all.  Nothing like I had seen when I was doing 200 6BR cases at a time and tumbling for 3 hours and the cases were just as clean.

Long story short…  clean as few cases as possible or buy more pins.  I think the brass has to be swamped by pins and the cases need to be buried and separated as much as possible from the other brass if peening is a concern.

I doubled my pins to 10 pounds. Or you could use 5 lbs of pins and use smaller batches of brass.  It does the same thing.  My point is that most people are using too much brass to pins and the peening is coming from the brass on brass contact not from the pins.  The pins are very, very gentle and work better to more the brass is buried in the pins.  Cleaning the brass inside is better in smaller batches.

I am going to say the ratio that is the most efficient as about 100 223 or 50 308/6br cases per 5 lbs of pins.  Tumble for about an hour or less.

250 Lake City 223 Cases by Weight

250 Lake City 223 Cases by Weight

It is definitely more effective.  Period.  Small batches take less time and the peening is reduced significantly.  Primer pockets clean much faster.

250 Lake City Cases in Tumbler with 10 lbs of Pins

250 Lake City Cases in Tumbler with 10 lbs of Pins

I am cleaning 223 from the ground to like new in one hour.  I fill the Thumbler 2/3 full.  Nearly exactly 250 cases. But the brass is clean is one hour.  Very clean.

Lake City Case Clean

Lake City Case Clean

Rinsing in denatured alcohol fixes all rinse problems and shortens drying time to half an hour.  I dry my cases at 180 degrees in my convection oven  🙂


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