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 ultrasonic tank, 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. Also it is used to remove specific greasy deposits.
Why not use IPA?
The main reason not to use IPA in an ultrasonic cleaner is because it 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 action of ultrasonic cleaning means the temperature of any fluid in the tank will rise by simple by turning the machine on. Even with the heater in the machine turn off, the fluid will start to heat up. IPA will start to evaporate and concentrated fumes will 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.
Some companies who do use the fluid in ultrasonic cleaners have fume extraction systems fitted. These prevent the build up of flammable vapours in the area above and near the machine.