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Chrome Eyeglasses

February 15th, 2008 | Author: Vision Care

Chrome Eyeglasses

Selecting The Correct Ultrasonic Cleaning Solution

The cleaning process is improved when appropriate cleaning solutions are employed to enhance cavitations by reducing the surface tension of plain water. Aqueous cleaning solutions do this by incorporating wetting agents, also called surfactants. The other important task of cleaning solutions is to disrupt the bond between the surface and the dirt. While water can dissolve many ionic contaminants, with any contamination that involves a fatty substance like oil or grease, water is ineffective as a solvent or cleaning agent.With the right cleaning solution, oils, fat and grease can become soluble in water.

What cleaning solution should I use?

The answer to this question depends basically on two things: 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 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 cavitations. 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 solution.

Cleaning solutions to avoid:

Flammable substances like gasoline, ether, and alcohol should never be used in an ultrasonic cleaner as the cavitations 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. Cavitations 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.

When should I change cleaning solutions?

If different cleaning processes require different cleaning agents, the tank must be drained, cleaned and refilled with the proper solution. This does not mean discarding the solution not being used. It can be stored and re-used several times until it is visibly dirty. If the cleaning capacity has decreased noticeably, it might be due to the cleaning solution being spent, but there are also other reasons why this can happen. One of the most common is an incorrect solution for the cleaning being done. For example, weak acids work great for calcium deposits, but they will not clean grease well.

Another reason for poor cleaning results can be traced to new cleaning solutions that have not been degassed. Gasses that are dissolved in the solution inhibit cavitations. Because cavitations will degas the solution with time, running the unit for 15 minutes before placing objects to be cleaned in the ultrasonic bath will fix this problem. Cleaning solutions also require the right temperature for optimal cleaning. Cavitations are optimal at temperatures between 50 and 65oC. Most ultrasonic cleaning units have a heater which can be turned on before cleaning to preheat the solution. Preheating the solution is also possible by running the unit as ultrasonic energy creates heat. This method, however, will increase the run-time and decrease the life of the unit.

Finally, it could be that the dirt is so stubborn that increasing the cleaning time is necessary. While cleaning jewelry might take only a few minutes, it can take 20-30 minutes to clean a greasy caked up fishing reel. If you suspect that your unit is not operating properly, you can test this by suspending one inch squares of aluminum foil in the solution positioned in the middle and a few inches from each corner of the tank. Filling the unit with water and then running it should perforate and wrinkle each aluminum foil square to a similar extent if cavitations occur evenly throughout the unit.

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