Elaine Corwin gave a listing of reasons for not putting things
directly on the bottom of your Ultrasonic cleaner. Like all of
Elaines notes the listing was clear, concise informative and
correct. Their is one additional and EXTREMELY important reason
for not putting a BEAKER on the bottom of the ultrsonic cleaner.
Cemented to the underside of the tank, is the transducer which
converts electrical energy to the vibratory energy which it
transmits thru the metal of the tank to the water. This
transducer in operation gets VERY hot and is cooled by the water
in the tank.( You can prove this to yourself by dipping your
finger into the water at the start of work, and repeating at the
end of the day, You will be surprised at how hot the water gets.
Of course I’m assuming that you are not using a heated tank. ) By
placing a beaker on the bottom of the tank you are reducing the
water thickness under the beaker to at most a thin film, which
provides little or no cooling. Use a beaker by all means…it
makes it so much easier to keep the tank clean. But put something
under it like a wire mesh bracket or even a few marbles.
My own history of woes with an ultrasonic cleaner includes one I
lost when I neglected to turn it off at night. The heated water
evaporated. The tank ran dry and left the transducer uncooled.
The result of my carelessness was a failure of the cement that
mounted the transducer to the tank. Repair cost estimates were so
high that it was easier to buy a new one