Re: ultra sonic cleaner question
Here is some of the information I found when researching ultrasonic cleaning.
Ultrasonic cleaners use sonic wavers to generate pressure fluctuations on the surface of the part. The pressure waves cause cavitation bubbles and when these bubbles collapse enough energy is released to remove contamination from the surface.
The reasons that the acidic cleaners (vinegar = acetic acid, lemon = citric acid, cream of tarter = tartaric acid half neutralized with potassium hydroxide) do a quicker job of cleaning the brass is because they etch the brass undercutting the carbon and particles.
These acids are weak and should not remove much brass, however, without doing some etch rate studies you cannot determine the amount of brass you are removing. As a conservative precaution, it would be prudent to minimize the amount of time in the acidic solutions.
Normal rinse procedures at work call for a minimum of 3 separate rinses in water after an acid bath. (It may take additional rinses depending on the water quality and temperature.) To save some money the first rinses can use tap water and the last rinses should use distilled water. If you are using vinegar, you can tell when the rinse is complete when you no longer have the vinegar smell. Once you no longer can smell the vinegar, switch to the distilled water for the final rinses. If you want to increase your rinse effectiveness you can use warm water and add some agitation (Ultrasonics would be effective here also).
Baking Soda is Sodium Bicarbonate (a base) and is listed as attacking brass. Because of this trait, it provides no real benefit to use this as a substitute for a good water rinse. The reasoning behind not performing the baking soda step is you will need to remove the baking soda to prevent it from attacking the brass. To remove the baking soda you will have to do a thorough rinse, so basically you are adding a step with little benefit.
