Ultrasonic cleaning fluids are used for getting rid of all the grime and dirt that settle in the crevices and on the surface of jewelry. So, they always contain a surfactant or a good wetting agent to increase cavitation – a process that creates millions of microscopic imploding bubbles that agitate the liquid and create the cleansing action.
There are several compounds used in the production of the cleaning fluid to enhance the process of ultrasonic cleaning. Their main purpose is for breaking the chemical bonds between the object being cleaned or the surface of the metal and the soil and grime. Several manufacturers sell different formulations depending on the kind of cleaning required and the nature of the material to be cleaned.
The cleaning fluid typically contains application-specific compounds and appropriate wetting agents, reactive components and detergents. Make sure that you select a cleaning fluid that corresponds to your requirement as closely as possible to keep away from any harm due to the fluid’s unsuitable cleaning action. In case of any doubt test a small piece of jewelry first. You can also ask your jeweler and verify that the cleaning solution will not have an adverse reaction with your jewelry. Most ultrasonic cleaning solutions for jewelry are soap based aqueous solutions and are generally non-reactive with most jewelry. Also note that there are certain gemstones that are not compatible with ultrasonic cleaners even with a mild cleaning solution. Know the natural property of your gemstones.
The cleaning fluids employed for jewelry have a pH of around 13 and are strong bases. They are water soluble and are comprised of sodium hydroxide, isopropyl alcohol and disodium cocoamphodiacetate. These aqueous solutions contain 70 to 80 percent water by volume . They also have a detergent-like odor. In general a cleaning fluid with such a composition is safe for use as an ultrasonic cleaning solution.
The ultrasonic cleaning solution should never be made of flammables or liquids with low flash points. The cavitation process during ultrasonic cleaning results to a spike in the temperature. This is due to the fact that it releases energy that is quickly converted into kinetic and heat energy. The by-products of bleach, acids and bleach, oxidizing agents and aluminum should never be used. These agents are hazardous and get readily ignited at the operative temperature of the ultrasonic cleaner. Their usage also results in extensive damage to the most important component of the ultrasonic cleaner, which is the corrosion-resistant stainless steel cleaning tank. So when there’s a need to use these agents, it is best to put them in a suitable cleaning container such as a glass beaker to avoid any harm.
There is also no need to replace the cleaning fluid after each cleaning cycle. A fresh cleaning solution is needed only when there is a a gradual decrease in the cleansing action of the liquid with the increased number of uses or when it appears visibly spent or dirty.
This article was written by Dr. Bob Sandor, a Director at Tovatech, a leading North American supplier of ultrasonic cleaners. When not busy running his company, he explores his fascination with the many aspects of various scientific & industrial devices. For more information on this article visit the Tovatech site from any of the above links.
