Could you tell us more about this particular unit
I was thinking about creating a thread detailing (with pictures) what I do and how I do it, today or tomorrow, after the range (so I have both gun and cases to clean!)
Long and short of it: ultrasonics work by creating (from the transducers built into the bottom of the cleaning tank) supersonic sound waves in the cleaning media (usually water, sometimes with cleaning agents added) that make millions of microscopic bubbles form on the water surface in contact with whatever you are cleaning. Called "cavitation" the continuously-forming bubbles form and burst at a fantastic rate, and the water that rushes in to fill the space occupied by the now-burst bubble provide the scrubbing action. The cavitation action is so small and so fast that you cannot see it with the naked eye. All you will notice is that the object being cleaned looks kinda out-of-focus, and in many cases the "filth" coming off of the object will just look like the smear of ink dissolving in the water.
Most manuals call for distilled water. I use tap water, since our house has a filtration system anyway.
Sometimes, cleaning agents are added. Mostly, these agents help break up the waters' surface tension, which enhances the cavitation effect. Other times, cleaning agents help dissolve oils and grease. Don't use anything with ammonia on soft metals like brass, you can dissolve the brass. Don't use anything with overly acidic additives (like a lot of lime/lemon/orange liquid dishwashing cleaners with anything that says "acid" in the ingredients list), it will dissolve metals faster. Personally, I like the Hornady Gun Cleaning Solution, mixed per instructions with water for cleaning guns and components, and the Hornady Brass Cleaning Solution, mixed per instructions with water for cleaning brass as the first step in reloading.
The u/s cleaners I have and use have various warnings about not putting your hands or fingers into the solution while the machine is running. Apparently, the ultrasonic waves conduct thru blood as well (a liquid, right?) and have undesireable effects on bone and tissue. Not wanting to end up with jellified fingers, I have never personally tried it, nor do I know anyone who has, nor do I know of any instance when injury has resulted. Does not mean it hasn't happened before.
I use the 2.5L u/s cleaner from Harbor Freight ($75 available here:
http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html) Yes, I know I know, if WallyWorld is king of made in china, Harbor Freight is queen. But it does the job. Not well, nor as quickly as others, but at about 1/10 the cost of my other gizmo.
I also use the Crest Powersonic ($775 available here:
http://www.sonicsonline.com/cp500-crest-powersonic-ultrasonic-cleaner.html) but for my demo I will use the cheaper one (since not many will be able to afford this monster).
Cleaning is easy as 1-2-3. Detail-stripping is highly recommended, especially for a first-time cleaning or for really dirty handguns, because then the crud comes off, it needs a place to go in order to get it out of the part....gravity pulls it down, but... Anyway, detail-strip, then put water into the cleaning tank, adding whatever cleaning agents you want, plug it in, put the parts in, turn it on (they all have timers, usually an 8-minute max, to prevent the transducers from frying). At the end of the cleaning cycle, turn the parts over, repeat. At the end of that cycle, inspect. If it is still dirty, repeat. With the Harbor Freight unit, you need to repeat a lot. With the Crest unit, one 8-minute cycle per side of say a slide and frame will do the job.
Take the parts out, immediately rinse in hot running tap water (heated parts dry faster). Then blow everything out with an air compressor. I have mine set to 100psi, and blow out structured components (slides, frames, magazine tubes, etc, not needed on springs and things you can immediately wipe dry), just be careful not to drop anythig or blow tiny springs and detent pins you have overlooked!
When done, there is not a single drop of lubrication anywhere on the metal. It is bone-dry. Any added lubricant or anti-rust materials are gone. Rust is your first and immediate enemy. I lube everything down (with Gun Butter) and wipe all the excess off. Then I reassemble and lube as per instructions.
It does not damage polymer frames and parts. It will cause wood grips to expand, warp, and break. It will not loosen screws you did not remove beforehand.
In my experience, it can affect paint markings, like sight dots and the red dot on safeties. I have had all 3 dots on my XD-9 vanish, but has not affected any of my other handguns. I have had a Trituim pellet burst on the nightsights of my Beretta 92G. But that's it.
I do not scrub the bores, I do not need to scrub any other parts for cleaning. For the bores, I run an oiled patch thru and follow-up with clean patches (and a full-diameter jag tip) until the patches come out clean. I do this twice.
And that's it!