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August 20th, 2015

How to Clean Brass with an Ultrasonic Cleaning Machine

Ultrasonic Cleaning RCBS Ultrasound .308 Winchester 7.62x51 brass casings

Do you have some old, tired brass that needs a thorough cleaning — inside and out? Consider using an ultrasonic cleaning machine. When used with the proper solution, a good ultrasonic cleaning machine can quickly remove remove dust, carbon, oil, and powder residue from your cartridge brass. The ultrasonic process will clean the inside of the cases, and even the primer pockets. Tumbling works well too, but for really dirty brass, ultrasonic cleaning may be a wise choice.

READ FULL UltimateReloader.com Article on Ultrasonic Case Cleaning.

Our friend Gavin Gear recently put an RCBS Ultrasonic cleaning machine through its paces using RCBS Ultrasonic Case Cleaning Solution (RCBS #87058). To provide a real challenge, Gavin used some very dull and greasy milsurp brass: “I bought a huge lot of military once-fired 7.52x51mm brass (fired in a machine gun) that I’ve been slowly prepping for my DPMS LR-308B AR-10 style rifle. Some of this brass was fully prepped (sized/de-primed, trimmed, case mouths chamfered, primer pockets reamed) but it was gunked up with lube and looking dingy.”

UltimateReloader.com Case Cleaning Video (7.5 minutes):

Gavin describes the cleaning exercise step-by-step on UltimateReloader.com. Read Gavin’s Cartridge Cleaning Article to learn how he mixed the solution, activated the heater, and cycled the machine for 30 minutes. As you can see in the video above, the results were impressive. If you have never cleaned brass with ultrasound before, you should definitely watch Gavin’s 7.5-minute video — it provides many useful tips and shows the cleaning operation in progress from start to finish.


The RCBS ultrasonic cleaning machine features a large 3-liter capacity, 60 watt transducer, and 100 watt ceramic heater. The RCBS ultrasonic machine can be found under $140.00, and this unit qualifies for RCBS Rebates ($10 off $50 purchase or $50 off $300.00 purchase). RCBS also sells 32 oz. bottles of cleaning concentrate that will make up to 10 gallons of Ultrasonic Solution.

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September 30th, 2013

Ultrasonic Case Cleaning — What’s the Optimal Dwell Time?

If you’ve read our feature story on Ultrasonic Cleaning by Jason Baney, you’ve seen the remarkable results that can be achieved with this method. Ultrasonic cleaning has many advantages over traditional tumbling methods of case cleaning. There is no dust or media residue to remove from the brass, and when done right, the cases come out clean and shiney, inside and out, even the primer pockets.

In its Benchtalk Archives, Brownell’s has an excellent article discussing Ultrasonic Case Cleaning. Brownell’s staff compares results, with measured dwell times from 5 to 75 minutes, using both Mpro-7 and HCS 200 cleaning solutions. Tests are performed with once-fired and 5X-fired Tactical 20 (Tac20) cases, as well as once-fired .260 Rem Cases. The article also compares the results from ultrasonic cleaning vs. tumbling in walnut media. Below are Brownell’s results for Tac20 cases with the HCS 200 (non-acidic solution). Go to Brownell’s article for MPro7 results and Rem 260 results.

HCS 200 Cleaning Solution Test
Procedure — Solution was de-gassed for 15 minutes, then 63 Tac20 cases were placed in a single layer, in stainless steel mesh basket. The temperature of the starting solution was 102° F. When the cases were removed the temperature was 110° F.

Once-Fired Tactical Twenty Cases (HCS 200) — Observations
5 minutes: The exterior of the cases are not significantly brighter/cleaner. The primer pockets and case interiors are still dirty.
10 minutes: Exterior of the cases are brighter. 70% of the cases show some degree of cleaning of the primer pockets. Little difference seen inside the case, but case mouths are cleaner.
15 minutes: Case brightness is about the same. Still only 70% of the primer pockets are clean, but a larger portion of each is cleaner. A Q-tip swabbed inside the cases shows that carbon/powder residues are loosening up.
20 minutes: Case exteriors are brightening up. 80-85% of the primer pockets are about 90% clean. The insides of the cases and case mouths are cleaner.
25 minutes: Cases are brighter/cleaner than even new brass. 80-85% of the cases have almost completely clean primer pockets. The inside of the cases are 80-90% clean.
30 minutes: The insides of the cases and case mouths appear to be completely clean. 87% of the primer pockets are virtually 100% clean. 13% of the cases had stubborn primer pocket residue that could not be completely removed.
60 minutes: Eight cases (13%) were placed in the tank for another 30 minutes to try to remove the remaining residue in their primer pockets. Six out of the eight cases were completely clean.

Five-Times Fired Tac20 Cases — Observations
30 minutes: Based on the above observations, I didn’t begin to observe these 5-time fired cases until after 30 minutes: The exterior cases are bright/clean. Brighter than new cases. The primer pockets on 75% of the cases are 75% clean. The remaining cases had primer pockets that were only 25% clean. The inside of the cases appear to be clean.
65 minutes: 25% of the primer pockets were 95% clean, 25% of the primer pockets were 90% clean, 25% of the primer pockets were 85% clean; and 25% were 80% clean.
75 minutes: 75% of the primer pockets were 90% clean.

How Does Ultrasonic Cleaning Work?
The Brownell’s article explains: “Ultrasonic cleaning uses high-frequency sound waves (generally between 20-80 kHz) to remove a variety of contaminants from objects immersed in a liquid. The result of these high-frequency sound waves is a process called cavitation. These high frequency bursts of ultrasonic energy produce a three-dimensional wave of alternating positive and negative pressure areas as the sound wave passes through the solution. During negative pressure, microscopic cavitation bubbles form and will continue to grown until they reach resonant size. As the positive sound wave passes, the pressure rises rapidly and implodes these tiny bubbles. Before these minuscule bubbles implode they store a tremendous amount of energy. These bubbles can be as hot as 10,000 degrees and have as much as 50,000 lbs per square inch of pressure. This sounds alarming, but you have to remember that these bubbles are microscopic in nature and pose no harm to anything, unless you are a carbon /powder residue deposit on a cartridge case!

When this cavitation bubble implodes near your brass case, it transforms the bubble into a jet about 1/10th of its size. This jet of energy can travel as fast as 400 km/hour. At 43 kHz, as is the frequency for our L & R HCS 200 ultrasonic cleaner, this is happening 43,000 times per second. This micro-burst of extreme energy is responsible for removing contaminants from the surface of your cartridge brass. Ultrasonic cleaning can reach into crevices and inaccessible areas and remove surface debris that can’t be cleaned by any other process.”

Photos and quotes © 2007-2010, Brownells®, Inc. All Rights Reserved, Used with Permission.

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November 16th, 2012

New Hot Tub™ Ultra-Sonic Cleaning Machine from Hornady

Hornady has announced new products for 2013. These include a number of new bullets, along with new loaded rifle, pistol, and shotgun ammunition. Perhaps most interesting for precision reloaders is Hornady’s new jumbo Ultrasonic Cleaning machine (MSRP $658.33). Featuring a 9-liter capacity, the new Hornady Hot Tub™ is long enough to accommodate and clean a 16-inch AR-15 upper. Along with its large capacity, the Hot Tub has many advanced features.

Hornady Hot Tub Cleaner

New Large-Size Ultra-Sonic Cleaning Machine — the Hot Tub™
For 2013, Hornady will be offering a new, jumbo-sized ultra-sonic cleaning machine that can handle big parts and accessories. In addition to having four (4) transducers, there is also a heating element that enhances cleaning action. Hornady says that “the microjet action of the Hornady® Hot Tub™ removes carbon residue and other debris from cartridge cases, gun parts and other metal equipment.” We know that ultra-sonic cleaning works well on cartridge cases, provided you have a good machine, a suitable solution, and run the machine for an appropriate time.

Hornady Hot Tub Cleaner

The new Hot Tub is well-equipped out of the box. One 1.7 quart inner tank comes with the unit and can be used in the main tank for cleaning multiple smaller batches or to use separate solutions at the same time. Additional inner tanks can be purchased separately. Hanging cords have been integrated into the design to allow large objects to take full advantage of the ultrasonic energy. Additionally, the Hot Tub® features integrated drain pans in the lids, a small parts basket, a degas function and five (5) temperature settings from 100-140°F.

Hornady Hot Tub Cleaner

Watch Video to See Hornady Hot Tub Ultra-Sonic Cleaning Machine in Action

Hornady Hot Tub Cleaner

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September 27th, 2009

Improved Ultrasonic Cleaning with Citranox

Citranox Case CleanerForum Member Dave B., aka “Gunamonth”, is a chemist/physicist with decades of experience working with the ultrasound process. He has achieved great results cleaning cases via ultrasound. Dave tried a variety of solutions and he favors a mix of water and Citranox®. This achieved the best results, and did not require a separate neutralizing step if you rinse the cases thoroughly after. Citranox, mixed 1:75 or 1:100 with water (distilled H20 is best), is inexpensive to use. Phospate-free Citranox® contains a blend of organic acids, anionic and non-ionic surfactants and alkanolamines. For more information on using Citranox®, check out THIS FORUM THREAD.

Dave notes: “I had a lot of communication with the technical VP of Alconox about trying to clean fired cases with an ultrasonic unit. He sent me a copy of his ultrasonic cleaning manual and recommended a product called Citranox®. So far I’ve been very impressed. With once- or twice-fired brass they clean up very quickly. The worst cases I tried were 6 Dashers that had been fired ten times with Varget and never cleaned. The worst fouling was in the bottom of the case around the flash hole. They took longer and I used a more concentrated cleaning solution but they did come out clean. The price is reasonable. I paid $35 a gallon and for once- or twice-fired cases I dilute the cleaner 100 to 1. There is much less chemical reaction with the brass than there is with vinegar. No weird colors, just shiny bright. I even used it with hot water, which speeds up the cleaning process. No need to neutralize. Just rinse in running water and they’re squeaky clean. The cleaner is mostly detergents with a little citric acid. Even at a 1:75 ratio my $35 worth of cleaner will make 75 gallons of solution. It doesn’t seem to be reusable but 75 gallons is a whole lot of solution when I only use about two cups at a time.”

The price has gone up a bit since Dave acquired his Citranox, but Amazon.com sells Citranox for $40.00 per gallon, or you can buy a gallon of Citranox from LabSafety Supply for $46.40.

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