Diamonds are forever, so the saying goes. Unfortunately, this is not always the case. Physically, yes; the diamond is reputed to be the hardest substance on earth. But if it’s about its lustre, then we’re talking a different beat here. Dust and dirt can form a thick, ugly covering on the diamond’s surface, drastically reducing the stone’s fire and shine. Sweat and oil excreted from human flesh can also taint the precious jewel. If that grime isn’t cleaned out, it will adhere onto the diamond’s surface, eventually forming a crust that will be virtually impossible to remove with conventional methods.
At this point, it’s time to bring out the big guns of diamond maintenance: the ultrasonic cleaner. This is a device that utilises ultrasound being passed through an appropriate cleaning solvent. An ultrasonic cleaner can get rid of the thickest filth, restoring the life, fire, and shine of a diamond.
How does it work? The dirty jewellery is placed and suspended into the cleaner’s chamber, which is filled with a special aqueous or organic cleaning solution. Ordinary clean water can be used, but cleaning fluids solutions are more effective because they’re “wetter” than water. These solutions also contain ingredients that are designed to reduce surface tension and to make cleaning more effective.
Okay, the jewellery to be cleaned is now neatly suspended in the solution. A transducer is then lowered into the liquid (in some cleaners, the transducer is built into the chamber). Once activated, the transducer generates ultrasonic waves in the fluid, altering in size in sync with a pulsating electrical signal (this process is called oscillation). The oscillating waves “tear” the cleaning solution apart; if it’s just water, the waves wouldn’t be strong enough to “tear” it. This action, called cavitation, leaves behind millions upon millions of partial vacuum bubbles.
When these bubbles the surface of the diamond or jewellery setting, they collapse, releasing vast levels of energy and heat. In fact, the explosive force can sometimes reach 20,000 pounds per square inch; temperatures can reach 5,000 Kelvin! But the bubbles are so tiny that all they do is knock out dirt, contaminants, and particles. You can also increase the frequency to reduce the nodes between cavitation points, which produce even smaller bubbles. These tiny bubbles can get in the tiniest cavities, so cleaning jewellery with very intricate detail won’t be a problem.
Ultrasonic cleaning usually takes six to eight minutes. After that, the jewellery will be thoroughly clean, probably for the first time since it was bought.
Jewellery are not the only objects that can be cleaned through this method. Industrial products such as rods, cables, and wires are also subjected to ultrasonic cleaning before being put on the shelf. Medical instruments may also be cleaned through this method although they are subjected to another process for sterilisation.
Let ultrasonic cleaning breathe life into old, dirty diamond jewellery.