While most of our ultrasonic cleaning posts provide practical advice on how to clean specific items there’s more to the science of the process. In fact effective ultrasonic cleaning is a combination of ultrasonic frequency and power, the temperature of the cleaning solution, the time it takes to complete the job, post-cleaning procedures if required, and cleaning solution chemistry.
Three Cleaning Solution Chemistries
A wide variety of cleaning solution chemistries are on the market but just about all commonly used solutions fall into three categories: alkaline, acidic and neutral. While terms like alkaline and acidic may cause some initial concern we are confining our examples to highly diluted biodegradable solutions in water.
The cleaning solutions mentioned below are but a small part of the products available from Tovatech, where we take pride in matching cleaning chemistries to cleaning challenges.
Alkaline Cleaning Solutions
Alkaline cleaning solutions (sometimes referred to as caustic solutions) are exemplified by the elma tec clean A series of concentrates. Of these we bill elma tec clean A4 as a nearly universally applicable concentrate for just about every need in the lab and workshop. Diluted to 2 to 5 % with water and operated at a bath temperature of 50⁰C to 80⁰C it’s great for glass, ceramics, plastics, rubber and most metals except the lighter alloys. We recommend elma tec clean A4 to clean carburetors, fuel injectors, engine parts, newly machined parts, and similar components to remove smoke, grease, soot, wax, coolant oils, loose metal particles and dust.
A milder alkaline solution, elma tec clean A1, is recommended for glass, optical assemblies, ceramic substrates and electronics. We recommend it for cleaning printed circuit boards used in PDAs and similar devices. It safely removes soldering flux, oil, dust, water damage, coffee, tea, soft drinks, milk and fingerprints when diluted to 3 to 10% with water and operated at 40⁰C to 80⁰C (65⁰C for PCBs).
Ammonia-containing mildly alkaline elma tec A2 is a good selection to remove oil, fat, grease, sweat, oxides, polishing compounds and similar contaminants from ferrous metals and non-ferrous brass, copper, bronze, precious metals and jewelry when diluted to 3% to 5%. Its ammonia content makes it especially useful for brightening brass and copper.
Acidic Cleaning Solutions
Acidic ultrasonic cleaning concentrates are used for tough cleaning jobs and can involve a chemical reaction to remove contaminants. Emulsifying elma tec clean S1 diluted to 1 to 5% removes oxide films, rust, lime, grease, oil, corrosion, and mineral deposits from nonferrous heavy metals, stainless steel, aluminum, light metals, brass, steel, plastics and glass. Stronger acidic solutions are available for these materials along with steel, iron, gray cast iron, hard alloys, nickel, nonferrous heavy metals and precious metals. Remember to remove steel products immediately after de-rusting and rinse with an anticorrosive such as elma-KS for temporary corrosion protection.
Neutral Cleaning Solutions
Elma tec clean N1 is phosphate-free emulsifying neutral cleaning concentrate for gentle cleaning action. It is used for the treatment of highly sensitive pieces to remove oil, grease and other organic particles. While it is safe for all metals, plastics, ceramics, glass, and rubber it should be tested before using on magnesium. When used in an ultrasonic cleaner it is diluted to 2 to 5% with water. Without ultrasound dilute it to 10%.
Contact the ultrasonic cleaning professionals at Tovatech for an in-depth discussion of your cleaning challenges and for sensible recommendations on the correct ultrasonic cleaner in terms of frequency and temperature control, and our recommendation for the best cleaning solution chemistry.