ultrasonic cleaners

[garystewart]

With all the ethenol gas and lousy carb cleaners, getting clean carbs has become difficult. We are thinking about trying a $70 Harbor Freight unit. Anybody have any experience with this type of unit

[markkw]

Something you may want to consider is the ultrasonic cleaners are prone to destroying pot metal, aluminum alloys, pearls, certain fracturable substances like stones, gems, ceramics & glass and substances that are susceptible to cavitation erosion. I actually did considerable testing and then a lot of research on ultrasonic and ended up building my own cleaners for the printing industry. One printer purchased an ultrasonic unit costing around $40k and ended up having to clean the print heads by hand. Ultrasonic only works for certain things and whatever you put in it must be capable of withstanding the high frequency vibration and resulting cavitation which is how ultrasonic produces mechanical action.

As stated above, certain materials are more susceptible than others to being damaged by ultrasonic - the same goes for the crud you're trying to get off, some will come off easily, other crud will remain completely unaffected by ultrasonic which is why ultrasonic pushers recommend the use of "special ultrasonic cleaning solutions". The reason these "special ultrasonic solutions" are recommended is because they're using the acid or alkaline in the solution in an attempt to attack those materials that are not affected by the ultrasonic cavitation action. Most of the "ultrasonic cleaning powders" are a combination of abrasives and detergent that will readily destroy critical dimensions such as the brass needle bushings on paste ink injectors and the stainless steel head pressure regulator orifice. These powders are generally mixtures of high-alkaline detergent and sodium bicarbonate which is both mechanically abrasive and increases the alkalinity even further.

What started all this for me was that the printing inks and dyes were alkaline base as were the "special ultrasonic cleaning solutions" and therefore, the "special solutions" were useless because alkaline materials must be attacked with acids and acids must be attacked with alkaline. Ultrasonic is extremely overrated because of its history as it found it niche in the medical industry and as people saw ultrasonic this and that in their doctor's and dentist's offices, it produced the mindset that "if my doctor trusts it, it'll work for me". The jewelry industry was the next target as the majority of crud on jewelry is acid-base from human skin & sweat where the alkaline "special solutions" worked well. It didn't take jewelers long to figure out that not all items are ultrasonic-safe because the cavitation action and/or alkaline solutions readily destroyed some jewelry costing them a whole lot in liability. Seeing the potential market in the print industry, I jumped into this with both feet to the point of ordering special ultrasonic generators and running test after test after test eventually coming to the realization that while ultrasonic works well to de-crud medical & dental devices, it's not worth a hoot for the majority of industrial crud. After designing the special cleaning machine for the printing industry, word of mouth got me commissioned to build a semi-automated cleaning machine for a company that remanufactured gasket cutting machinery. They were also suckered into purchasing a huge ultrasonic machine only to find out that when the ultrasonic generator failed, the work came out of the machine in no different condition than that work run through the machine when the u/s generator was working - they were still wasting as many man-hours manual cleaning after the u/s machine was used as before they used it. That was a somewhat extensive application but the end result was cutting their pre & post cleaning man-hours by 80%; cut their total process time by 50%; cut their cleaning solution costs by 40% and hazardous waste disposal costs by 70%.

Most detergents are alkaline but those with "citrus, D-Limonene, vinegar, ect" are acidic - whether alkaline or acidic, both are detrimental to aluminum, pot metal and plated items. Ethanol is pretty much neutral but readily carries sulfides and acids, the highest acid content comes from the latent and absorbed water that is either intentionally added or is drawn-in by the ethanol. Metal parts, especially aluminum & pot metal, are highly susceptible to the corrosive effects, secondary to the corrosion formation is that ethanol, even in very low concentrations, promotes rapid degradation of the gasoline causing far more rapid dissolution of the waxes that are added to replace lead. End result is having corrosion combined with varnish/wax deposits. Okay, so you know all that but it leads to the point that the wax/varnish deposits are highly flexible and adhesive and therefore not susceptible to the mechanical cavitation action created by ultrasonic waves nor are they water soluble. Wax/varnish deposits can be cut the fastest using strong chemical solvents like lacquer thinner or MEK or somewhat slower but safer using denatured alcohol (solvents can be run through a filter network and re-used many times to reduce cost). The ultrasonic cavitation effect on already corroded aluminum & pot metal parts greatly increases the level of damage well beyond that caused by the corrosion alone.

All is not lost provided the corrosion damaged the parts beyond use, once the wax/varnish deposits are removed, the corrosion is best removed utilizing a mildly alkaline high surfactant water based solution combined with moderate frequency mechanical agitation which helps prevent causing further damage such as that seen by cavitation. Most corrosion, especially that formed on aluminum and pot metal is highly susceptible to aqueous thermal shock treatment as long as such methods remain with the acceptable parameters of the material(s) being treated. Because of the economy I had put my plans to produce smaller cleaning machines on the shelf but now that things are starting to look a little better, as soon as the pending gun work is cleared off the bench in the next couple weeks, I'm going to put some multi-purpose machines together and see what the market looks like. Sent you (Gary) an email concerning your specific application.

Here's what others have posted on various forums about the H-F 2.5L ultrasonic cleaner:
Worked great until a week after the 90-day warranty expired then it quit.
Some rocks in a coffee can would be useful than this POS!
Ran two cycles and stopped working.
Used it for two weeks and it stopped working, found lid drips water into circuitry, shipped it back and HF said it was abused and wouldn't warranty it.
2.5L H-F u/s cleaner sucks! Paid return shipping three times, none of the four units lasted more than 20-30 cycles, finally got a refund but I'm out more than what the unit cost in shipping that was not refunded.
Lasted about three weeks until the water from the cover caused it to short out.
I used it once a week and it stopped working after warranty expired.
Stopped working after about 50 cycles and didn't clean very good anyway.