We get asked if Isopropyl alcohol (IPA) can be used safely in an ultrasonic cleaner and the answer is normally no, it cannot. Unless you want to invest in a blast proof cleaner, using this highly flammable chemical in an ultrasonic tank of any size is very dangerous.
Isopropyl alcohol (IPA) is sometimes used for cleaning electrical components such as PCB’s (printed circuit boards) because it evaporates quickly and leaves no residue. It can be used to expel water from mobile phones that have been exposed to varying degrees of moisture.
The main reason not to use it in an ultrasonic cleaner is because IPA can become unstable and has a low flash point. A “flash point” is the temperature at which a particular fluid gives off sufficient vapour to ignite in open air when given an ignition source. Very similar to petrol. A single spark will ignite petrol without actually touching it because the vapours rising from the petrol fumes are flammable.
The very action of ultrasonic cleaning means the temperature of any fluid in the tank will rise just by turning the machine on. Even if there is no heater in the machine, the fluid will start to heat up. IPA will start to evaporate and concentrated fumes build up over the tank. All it takes is a spark of static electricity to ignite those fumes and you will have a fire ball in a split second.