You bought a pair of beautiful, gleaming diamond earrings a few months ago. However, as you put them on today, you notice that the earrings have lost their shine and lustre. Yet, you remember you took very good care of them. You made sure not to get them dirtied. You washed them with mild soap and water regularly.
Well, it turns out that the jewellery is really grungy, but you are unable see the dirt. That’s because it has developed into a thin film that obstructs the light from striking through the diamond or reflecting from the stone. That film coats the metal also, which lessens the jewellery’s reflective qualities. Tiny bits of dust and dirt penetrate to the microscopic pits in the metal setting and the diamond itself. Furthermore, after mixing with moisture, oil, and salts from your skin, the dirt has dried and crusted like cement. With these factors, it is impossible to take away all this gunk even with faithful washing and brushing.
Thankfully, that dirt can be easily removed through a high-tech process called ultrasonic cleaning. Ultrasonic cleaning utilizes high frequency sound waves, usually in the 20 to 400 kilohertz range to make your jewellery neat and tidy. Here’s how ultrasonic cleaning works.
The piece to be treated is immersed in a compartment in an ultrasonic cleaner. The compartment is then filled with a suitable cleaning liquid. Ordinary water can be utilized as a cleaning fluid, but this is not really effective because of the high surface tension of water. Thus, an aqueous or organic solution is instead used. The cleaning solution contains surfactant ingredients that lessen surface tension, essentially making it “wetter” than water. The [correct|appropriate|suitable|recommended|right} cleaning liquid to be used depends on the type of jewellery being cleaned. Most cleaning liquids utilized for ultrasonic cleaning are warm, at around 50 to 65 degrees Celsius. In medical applications, however, the solution used is typically at a cooler temperature, not more than 38 degrees Celsius, to avoid protein molecules from coagulating.
The jewellery is placed in the solution, suspended so it won’t touch the bottom of the container. That’s because the parts of the jewellery that is not in contact with the fluid are not cleaned. Once the item is securely suspended, an ultrasonic transducer which is either built into the cleaner or lowered into the solution is turned on. The transducer then creates ultrasonic sound waves that change in size in coordination with an electrical signal that is oscillating at ultrasonic frequency.
This action creates compression waves in the cleaning solution that agitate, or “tear apart,” the cleaning solution. The agitating action, called cavitation, creates millions upon millions of microscopic voids or partial vacuum bubbles. As the bubbles attach themselves to the} jewellery, they collapse, or explode, with a big amount of pressure. Oftentimes, the energy released from a collapsing bubble can sometimes reach 20,000 pounds per square inch! However, the bubbles are so tiny that it is impossible for the energy to damage the jewellery. That explosive force is enough to strip of and get rid of surface dirt and contaminants such as dust, oil, pigments, rust, grease, algae, polishing compound residue, and others.
The bubbles can also go inside invisible holes, cracks, and recesses that can’t be reached through normal brushing or polishing. In other models of ultrasonic cleaners, you can also regulate the frequency of the sound waves. The higher the frequency, the smaller the cavitation bubbles, which allow you to clean very intricate details.
So if you wish your diamond earrings and engagement rings to be cleaned completely, opt for ultrasonic cleaning.