HF ultrasonic cleaner report

Good report, I've been wanting to get one of those for my shop.

Pete C.

Dammit, now I want one too........

Don, this is very nice, thanks for the report, keep us posted as to whether in continues to work after a while of use.

If your part has blind holes poke a wire into them to dislodge any air bubbles and allow the solution to get to the bottom. Randy

Wes, if you have crud in eyeglasses, try washing them with soap and bare hands. I do that daily and the rims stay completely crud free.

If you wear eyeglasses see how well it cleans the crud in rims and report back please.

Wes S

I could detect no audible sound at all -- but then, I am somewhat hearing-impaired. Some young folks can hear sound above 20 KHz, but I don't think anybody can hear 42 KHz. That's even above the audible range of dogs and rodents, except perhaps for bats.

There are some small "ultrasonic" cleaners that aren't ultrasonic at all. They just vibrate the juice with 60 Hz. That is not the same at all, not even close.

I couldn't find any specs on Branson's website or anywhere else re power level of those units. 42 KHz does seem to be a fairly standard frequency. There are higher freq units also, presumably for smaller parts.

OK. They're just an electronic power oscillator driving a transducer. If the 'ducer craps out it's history but I'm sure I could repair or replace any failed electronics. I have never had a sonar transducer fail. I've sometimes wondered if one could make a cleaner from one of them, though their frequencies are considerably above 42 KHz, more like 200 KHz.

Geez, Ig, you should be able to find a submarine or Mark 46 torpedo 'ducer in your surplus shopping trips. Gen up a few hundred watts of the right frequency.... if you find some, get two and I'll do the elex! Pass on those requiring a forklift to move, please...

Don, I recall having junked a few transducers... Now you gave me a good idea as to what to do with the next one. Seems easy to build an oscillator circuit and amplify it with transistors. Thank you for a great suggestion.

I've used a Branson unit and it did indeed make some noise, just a modest buzz, presumably some harmonics, certainly nothing audible as a high frequency.

Pete C.

Shame i'm not in the US as I would love one and they don't seem to be that cheap here yet. As regards the longevity of ultrasonic cleaners all the people I have spoken to that have knowledge of them indicated that the main factor wasn't the electronics or transducers, but rather the quality of bond between the transducer and the tank. That was always mentioned as being the prime failure mode, when the transducer became debonded.

Not specific to this unit, another's comments mentioned debonding of the transducer wafers and the tank... This may be caused by placing relatively massive objects on the bottom of the tank, causing mismatched coupling of the wafer to the liquid; more heat is dissipated in the wafer, which either heats up the (very special) epoxy, or causes the wafer to fracture. So, always suspend stuff in the liquid, hung from the top.

Second fail mode comes after long use; the tank becomes perforated like the tinfoil you might want to use for testing. The ultrasonic energy causes cavitation.

Now, for the question I've been meaning to ask here, for a very long time... I have an older and fairly large Branson unit with 4 fractured wafers. I scored some wafers years ago, but an expert tells me that only 3m 214-series epoxy will survive in use, and that's not available in small enough quantities to be economic. Also, wafers have appeared on ebay from time to time. Same problem - the vendor does not sell the epoxy. Pity.

Anyone got any direct experience? thanks, in vibrating anticipation / mark

D> I picked up an ultrasonic cleaner last week. Links don't seem to

Seems easy, but it isn't the best course. Most piezo transducers are fairly high Q resonators with series resonance and parallel resonance very close together, rather like a quartz crystal. The best course is a power oscillator that uses the 'ducer itself to determine operating frequency, unless you want to watch meters and tune it periodically as in peak the grid and dip the final in a ham xmtr.

I have some background in efficient power oscillators, including a couple of patents, and I have quite a few 600-volt 40-amp MOSFETs on hand. Job 1 would be to characterize the 'ducer with it bonded to a suitable tank filled with water. That's easy enough to do in the lab. Then design the circuitry to match the 'ducer. A complete 'ducer will probably already have the necessary rear resonating mass and proper matching layer on the drive end.

Probably the 120-Hz modulation from an unfiltered supply.

Makes sense. A mechanical compression mount is best at higher power levels. The rear mount grabs a node in the resonant reaction mass. A good filled epoxy works well enough at the low power levels used by small cleaners and fishing sonars.

Don, thank you. If I come across a transducer, I will definitely ask you how to make a cleaner. That would be great.

If your expert really is an expert, I'd say that's the best direct experience you're likely to find.

However, Branson now uses a Langevin style 'ducer which I think is bolt-mounted. You can get these on Ebay for $29.50. It's rated for

The HF unit power rating is input power, so the delivered power is probably 40W or less -- which is probably ample for the small 1.25 liter tank.

Ig, note that the Q on this ducer is 1000. That sez your frequency had better be within 40 Hz of bingo -- and that will change with temperature, loading, and some other variables. If you're not spot on frequency then it won't accept any appreciable power.

Hi Iggy,

Are your eyeglasses worn everyday/all day and over 10 years old?

I didn't think so ;-)

I'd like to know the answer to the eyeglasses test too!