s: what part needs to be cleaned and what is the main contaminant? Put simply, if you want to clean the diamond in an engagement ring you will use a different cleaner than if you want to remove grease from a gear.
Indeed, there are many different options depending on the parts to be cleaned and the main contaminations. Not all of these involve expensive industrial ultrasonic cleaning solutions. As an example, removing calcium deposits (water stains, scaling) from chrome-plated metals, stainless steel or other corrosion resistant materials can be accomplished by using a weak acid like diluted distilled white vinegar or citric acid in conjunction with the power of an ultrasonic cleaner. But because weak acids can damage certain surfaces, it is best to use a little scrap piece to try it out first or ask the manufacturer of the part whether weak acids are safe to use with it.
For many light greasy contaminations such as the laboratory water bath dirt that accumulates on eyeglasses, jewelry, and SCUBA gear, a dilution of a hand dishwashing liquid will often do the trick. Because machine dishwashing cleaners often contain bleach they can be quite corrosive and could harm many surfaces especially because the corrosiveness is enhanced by cavitation. Further damage could result to an ultrasonic cleaner’s stainless steel tank. Because of the potential for damage machine dish washing detergents are not recommended for use in an ultrasound bath.
For trickier dirt like the grimy mixture of grease, algae, fish scales, etc. on fishing reels or dried paint on paint and air brushes, a stronger solution of an all-purpose household cleaner might be the right cleaning agent. Keep in mind that, fairly strong solutions (dilutions of less than 1:10) of many household cleaners can discolor certain metals, so caution is warranted.
Commercially available specialty cleaning solutions that are optimized for solubility, concentration, reactivity to temperature and materials, and for the ability to enhance washing and rinsing, can be obtained for each of these cleaning tasks. Additionally, commercially available specialty cleaning solutions might be the best solution for industrial cleaning processes that require more cleaning power.
Cleaning solutions to avoid: Flammable substances like gasoline, ether, and alcohol should never be used in an ultrasonic cleaner as the cavitation releases a lot of energy and high temperatures at the microscopic site of the imploding bubble. In a flammable liquid this could lead to an explosion.
Strong acids, bleach and bleach containing detergents like many machine dishwashing detergents can damage not only the stainless steel tank of the ultrasonic cleaner, but also sensitive surfaces of the parts being cleaned. If it is known that the parts will be able to withstand the treatment, however, bleach or acids can be used with the part submerged in a beaker containing the acid or bleach. The beaker is then put into the ultrasonic tank filled with water. Cavitation will occur outside and inside of the beaker, but the harmful chemical will not be in direct contact with the tank of the ultrasonic cleaning equipment.