HOW TO Clean Brass Cases using Ultrasonic Cleaners

As the title says, this thread documents a How-To (and Why-To) clean spent cases prior to reloading using Ultrasonic Cleaning System.

For this exercise, approximately 3,300 spent 9mm casings were accumulated, prepped, and cleaned using a Chicago Electric Ultrasonic Cleaner available from Harbor Freight Tools, using Hornady's Ultrasonic Case Cleaning Solution. This cleaner was selected because it is the one most likely to be purchased by reloaders (for cost considerations).

Time spent for cleaning was a total of two (2) days, following the procedure described in this thread.

Photos below are the raw brass from the range.

 

STEP-1: Wash the dirty brass.

Brass was washed in warm tap water with liquid dishwashing detergent. Do not use detergent with ammonia added, as this can discolor the brass and if allowed to soak (or not dried out quickly) can deteriorate the brass.

While transferring brass to a suitable washing basin, obviously bad brass (pierced or severly dented) was discarded, and aluminum and steel cases were also separated to be discarded.

Mix vigorously to allow soapy water to get inside the cases, eliminate air bubbles, and dissolve any accumulated dirt. Rinse very well.

When done, my procedure is to lay the washed brass on a towel in the sun, and this dries the cases very well and fairly efficiently (and cheaply), since I live in the High Desert and sunlight is my friend.

An alternative method would be to lay the cases out on a metal pan and place them in the oven for no more than 5 minutes at about 100-125*F. Being a cheapskate, I use sunlight.

In all stages of cleaning, case handling is done in batches. It is easier this way, and the small ultrasonic cleaner used can only do about 100-150 cases at a time.

 

STEP-2: Sorting.

Carefully inspect each case, perhaps use a magnet to remove any remaining steel cases.

Remove also all aluminum cases.

I like nickel cases, so I always separate these and handle them separately from brass.

It is important to separate all cases with Berdan Primers. A special primer removing tool is required for these, and they can break the decapping pin in the decapping die with moderate force on the loading ram of the reloading press. Cases using Berdan Primers have a distinctive double flash hole in them, as opposed to the single flash hole of Boxer Primers.

See photo below.

Cases circled in red are Berdan Primered cases.

Also note the filth inside the cases.

 

STEP-3: Decap and size the cases.

Using the instructions provided with your particular loading press, eject the spent primers out of each case. Since the brass is now relatively free of dirt and dust particles big enough to damage the sizing die, using a Tungsten-Carbide sizing die will negate the need to lubricate each case for this step. In the photos below, the primers have been removed and the cases resized using an RCBS TC 9mm sizer die.

Note the burnt filth and residues from the spent primers. If not removed, they will alter the physical dimensions of the primer pocket, making primer seating problematic, irregular, and potentially leading to either a primer detonation when seating (because of the excessive force needed to seat the primer into a dirty pocket), slam-fires (cased by protruding primers), or misfires (failure to detonate due to deformed primers).

The typical method of case prep at this stage would be to use a primer pocket brush inserted into the primer pocket, several quick turns of the case against the brush, and blow the powdery residue (and maybe inhale some of it). However, this repetitive motion gets boring (and dirty), and I do not believe anyone would willingly do this on 3,300 cases without developing carpal tunnel syndrome or going mad, or both. Electric case prep centers (by RCBS, Hornady, Lyman and others) help with this, by providing a rotating primer pocket brush and thus eliminating the twisting motion required. Still, it is boring and is still dirty, and you end up with powdered residues all over the place and in the air. An electric Case Prep Center is still an invaluable tool, especially for removing military primer crimps, bevelling and chamfering case mouths, and lubricating bottlenecked case mouths.

This is where ultrasonic cleaning solutions really shine. Pun intended.

 

STEP-4: Ready the Ultrasonic.

Below is the ultrasonic cleaner used in this How-To, and the cleaning agent used. Do not used just plain water, you may end up wanting to shoot the ultrasonic. It needs some sort of chemical cleaning agent to work well.

The Hornady Case Cleaning Solution recommends a mix of 40:1 of distilled water to cleaning agent. Since my home has a water filtration system built in, I used warm tapwater. The green liquid is the cleaning agent.

When full, turn the heating element of the cleaner ON (if present in your particular cleaner). For the Harbor Freight cleaner, simply pressing the TC button ("Thermal Control") activates a heater. There is a thermal protection circuit built in to prevent it from overheating and burning out, and the ultrasonic cleaning action also warms up the solution as it is being used.

The temperature can reach up to 120*F, so be very very careful with the mixed cleaning solution.

 

STEP-5: CLEAN!

Most ultrasonics (in fact, all the ones I am aware of) do cycles of up to 480 seconds (see the timer display above), or 8 minutes. This is to prevent the ultrasonic transducer from overheating and burning out, rendering the device useless. In this model of cleaner, the default setting is 90 seconds, and each press of the SET button raises it to 180, 280, 380 or 480 seconds.

The mixed case cleaning solution is not caustic nor is it toxic, but it can cause skin irritation to persons sensitve to chemical exposure (not me!). The solution will also be hot enough to cause a scalding injury. With this in mind, add about 100-150 or so cases into the cleaning tub being careful not to splash any of the cleaning agent. I sometimes put up to 300 or more cases in at a time, and just repeat more cycles to achieve the cleaning level I desire.

In between cycles, I agitate the cases (mix them around) in the cleaning tub using a fork or something similar.

When running, the unit will emit a low buzzing sound, this is normal. Bubbles may form and rise to the surface, this is also normal. The cleaning agent will become discolored, and this is also normal...it is the dirt and filth coming off the cases and dissolving into the cleaning solution.

Ultrasonic cleaners are used in dentistry, jewelry work, automotive and marine industries, and a lot of other activities to clean solid objects inside and out. The transducers in the base of the cleaning tub create supersonic sound waves that travel thru the cleaning agent. When these sound waves hit a solid object (like the brass cases shown here), millions of microscopic bubbles form and immediately burst, creating a scrubbing action that removes dirt, filth, grease, oil, and sometimes even paint, from the surfaces of the object being cleaned. The forming and bursting of the bubbles is called "cavitation". These bubbles are not visible to the naked eye.

Now, a word of warning: DO NOT IMMERSE FINGERS OR HANDS INTO THE CLEANING TUB WHILE THE UNIT IS RUNNING. I have read many warnings about this, and my understanding is that the ultrasonic waves transmit thru the flesh and resonate in the blood, causing this cavitation to occur in the tissues, bones, and skin. Presumably, enough exposure will cause the bones to jellify, but I cannot confirm this. I have personally heard of no instances of injury resulting from the immersion of a body part into an operating ultrasonic cleaner, but that just means I have never heard of anyone immersing a body part into an operating ultrasonic cleaner. I value my limbs and my digits, and refuse to experiment on this. I pass along the warnings on the instruction sheet of the ultrasonic cleaner, without endorsement.

Photos below show the start of the first cycle of cleaning, and the end of the 3rd cycle of cleaning. Note how dirty the solution became.

 

STEP-6: INSPECT AND RINSE.

Since the efficiency of any particular ultrasonic cleaner is dependent on the number and power of its transducers, the more the better, the higher the wattage the better. This particular model of ultrasonic cleaner has only one transducer, with a power of 35 watts. The Crest Ultrasonics HG-570 cleaner has two transducers of 55 watts each, and can clean up to 500 cases in a single 8-minute cycle, but costs around 10 times more than this model used here.

For this reason, using a scoop of some sort, inspect the cases in between cycles, to see if the primer pockets and case body are clean. If not, mix them around in the cleaning tub and repeat cycles. I have found that one mix of cleaning agent can clean up to 600 cases before it becomes too dirty to be effective.

If the cases are cleaned to your personal satisfaction (and remember: the point is to clean the primer pockets so you do not need to scrub them with a primer pocket brush), remove the cases into a deep basin of some sort, and rinse thoroughly with running water. It is vital that all remaining cleaning solution is rinsed off of the cases. Using hot tap water helps, as it heats the brass cases, making air-drying (in the sun) a lot easier. Water marks can form if the cases are not dried quickly enough.

Note the condition of the brass being rinsed, and drying out, in the photos below.

 

STEP-7: DRYING.

My preferred method is to lay a towel out in the sun (I have a work table on the back deck), and let the sun do the work of drying the cleaned cases. They can also be dried in an oven. If it is not possible to do either, a heat gun can be used, or a hair blower on HIGH heat.

It is vital to dry them out as quickly as possible, to prevent the formation of water spots that could lead to corrosion of the brass over time. If water spots develop in a batch that has already dried, run them thru a single cycle in the ultrasonic with water only, no cleaning agent, and then dry properly.

 

CASE INSPECTION.

Photos below compare the washed and decapped brass cases with those cleaned in an ultrasonic.

 

And this is the only physical "trash" that needs to be tossed....3,300 spent primers.

No airborne dustlike contaminants that you are likely to inhale, and your hands get "dirty" only when you sort and wash the cases the first time around.

 

And this is what 3,300 cleaned cases looks like....

 

AS A FINAL NOTE:

Ultrasonic cleaners DO NOT polish brass. The brass comes out initially very shiny and clean, this is because everything coating the brass has been removed.

After exposure to air, the brass will darken slightly. This is normal, and is due to reaction of the brass to air (and humidity, pollutants, etc). To achieve shiny brass, it is still necessary to polish using a case tumbler and polishing media or cleaning media with polish added.

This is the method that has worked for me for years, and my case prep and loading process is geared to this method. Users of progressive presses may find that this procedure will interrupt their loading sequence (since it inserts extra steps between decapping/sizing and case expansion).

This method will not work for all users.

Users of this method may achieve different results, depending on the type of ultrasonic cleaner used, the cleaning agent used, the proportion of the mix of cleaning agent used, and even the quality of water used.

This thread is posted as an informational How-To, and is not intended to represent the final word in case preparation.

I hope you have enjoyed reading thru it, and if you learned or discovered something from reading this, then I will be content.

Cheers!

 

You are very welcome, guys.

I hope you enjoyed the read!

Cheers!

 

Yer welcome, JWilli22!