Ultrasonic cleaner + highly flammable liquid! To do or not to do?

I do this all the time. My UC is the 2 liter 100 watt version with built in heater.
To save solvent and prevent any nearby sparks to ignite the vapor I always use tightly closed jam jar. The jar submerged in the water tank.

Solvent + UC is my favorite method for deep cleaning. One concept you have to understand: UC only helps you to agitate the dirt deep down to the smallest pores/crevices, solvent (be it hot soapy water, gasoline, IPA, etc…) still do most of the work,

Several guideline:

  • Do it in VERY well ventilated area. Away from any possible sparking or open flame.
  • Never heat it more than 80C. Different liquid has different optimal temp. For kerosene 60C is more than enough.
  • Leave 2/3 of the jar empty to contain the pressure. Liquid is not compressible, the jar will crack and burst otherwise.
  • Closing the jar acts like a pressure cooker, this make the bubbles smaller. Bigger and more visible bubbles eats your UC cleaning power.
  • Only use glass or metal jar, any soft container will dampens the precious sonic waves.
  • I prefer solvent with low flammability such as 95% IPA, kerosene, or diesel fuel.
  • COOL the jar by submerge it in cold water before opening. You don’t have to do this if you chose not to close the lid tightly.

I tried dedoming several LEDs with this method to unsuccessful results. Too aggressive and the phosphor quality is usually damaged. Careful slicing is the better way for more reliable dedomed LED.

[Clemence]