cross-posted from: https://lemmy.dbzer0.com/post/9350839

The manual for an ultrasonic cleaner says:

• “Cold, clean tap water is generally best suited as cleaning fluid. The cleaning effect can be enhanced by the addition of approximately 3 drops of washing-up liquid. Do not use caustic cleaners, ammonia, bleach or heavily perfumed detergents.” (emphasis mine)

I know a professional jeweler with decades experience who cleans jewelry (mostly gold) using “Mr. Clean”¹ and ammonia, diluted, in an ultrasonic tub. The cheap ultrasonic I bought for myself is not for pros - but jewelry cleaning is the advertised purpose and it has a stainless steel tub just like the pro models have.

So the question is, what’s the purpose of the ammonia avoidance guidance, and is the pro jeweler I know making a mistake by using ammonia?

UPDATE: I also have to question why the manual of my cheap domestic ultrasonic says to use cold water. Pro ultrasonics have built-in heating elements. The pro jeweler waits until the solution is hot before using it. So why is manual of the cheap ultrasonic saying to add cold water? Since there is no heating element in my cheap one, I’m tempted to start with hot water.

footnote:

① out of curiosity, is there a brand-neutral name for “Mr. Clean” (aka “Mr. Propre” in French regions)?

^ The above was posted in a chemistry forum to ask the question about ammonia, but I thought I’d try physics for the question about cold water. Normally I would want to fill the ultrasonic tub with boiling water for a better cleaning effect. But the manual says to use cold water, and it also says to give the device a cooling off period if it’s been used continuously. Is some ultrasonic hardware actually sensitive to heat?

I saw a build-your-own ultrasonic video where someone glued a ultrasonic generator to a sink to make a big ultrasonic tub. So I wonder if the cheap home device I bought might have used a glue as well, which perhaps would lose adhesion if the tub heats and cools (expansion/contraction).