Ultrasonic Aluminum Test - With Photo's

[Bill T]

I conducted this test in an effort to see actual results of what happens to unprotected Aluminum when subjected to Ultrasonic cleaning. The test sample is a piece of T-6 grade Aluminum I got from work, and applied a 500 finish to, then went over it with Happich Simichrome Polish to achieve as smooth of finish as possible. The above photo shows the finished piece before being subjected to any treatments. It's size is approx. 2 1/2" X 1 1/2" X 1/2" thick.



This was after 9-1/2 minutes in warm water with a small amount of Palmolive Dish Soap. There is not much change except for some very light, hard to see speckling.



This was after 21 minutes exposure to the Ultrasonic cleaner. More profound frosting of the metal has occurred, along with some enhanced speckling. The frosting appears to have taken on the circular pattern of the plastic tray it was resting on with multiple speckles occurring at 9, 12, and 3 O'clock positions around it.



This was after a full 30 minutes of Ultrasonic exposure. Much more profound frosting has occurred, along with deeper speckles. This would no doubt effect the finish of an Aluminium framed pistol if it had any degree of polish on it. While this test wasn't very scientific, I would conclude that it would be risky to expose any Aluminum firearm parts to Ultrasonic cleaning. I wish the photos were better, but you can see the Ultrasonic treatment did in fact effect the finish, which is what I was trying to determine.  Bill T.

[Graybeard]

I wonder how sound your conclusions are. Isn't pretty much ALL aluminum in use anodized? Your test used barel uncoated or untreated thus not anodized aluminum which I don't think would compare very well to what guns would be like. Why didn't you use anodized aluminum such as we'd likely have on our guns with aluminum?

[Bill T]

The reason this occurs in Aluminum is because it is not a very dense material. This allows the cavitation process to damage it more easily than steel, brass or other materials. I'm sure Anodizing might help to a degree, but I wouldn't bet a $1,000.00 gun on it. not after seeing what it does in just 30 minutes. They sell Ultrasound units that are large enough to immerse a entire AR-15 upper and lower. I wouldn't do it. Besides, most Aluminum firearm components aren't subjected to anything that is going to get them that dirty. I bought this unit for my AR-15 bolt and carrier assemblies. They get a lot of carbon fouling. Ultrasound cleaning makes them look like new in just a few minutes without making a mess scrubbing the stuff off.  Bill T.

[Bill T]

Another thing to remember is that the coatings the firearm industry uses on Aluminum, (Phosphate and Anodizing), is very shallow in depth. Most are only .0002, (two ten thousands), of an inch thick. The slightest scratch anywhere will expose the unprotected metal beneath it. This would allow for almost immediate pitting if it were exposed to Ultrasonic cleaning.  Bill T.

[SDS-GEN]

With a good ultrasonic detergent it should take no more than 5 minutes to clean.  Aluminum is very soft and the dull finish is most likely abraded by whatever the piece was sitting on.  I am a jeweler and occasionally leave things in the ultrasonic for extended periods (hours).  Most soft metals are not effected (gold, platinum, copper, nickle silver, brass)  brass will tarnish.  Silver and aluminum can get dull spots if left in too long.  This occurs when microscopic pores become filled with grit from polishing then the ultrasonic pulls the grit out and vibrates it around on the surface of the metal.