Choosing an Ultrasonic Detergent for Your Application (2024)

An ultrasonic detergent (also called an ultrasonic soap) is added to your ultrasonic bath to aid the cleaning process. While there are some detergents that can be used in a wide range of applications, sometimes a specialized solution (or not solution at all) is necessary.

Ultimately, the goal is to select a detergent that offers the right level of cleaning to remove all contaminants but that doesn’t cause damage to the part being cleaned. To ensure you are using the correct ultrasonic detergents for your application, it’s a good idea to familiarize yourself with the various types.

In this article, we reveal exactly what ultrasonic soaps are and how they work. We also discuss the types of solutions available and their general uses.

Ultrasonic cleaning works through a process called cavitation. You place your object or component to be cleaned inside a bath filled with your cleaning solution. Transducers create ultrasonic waves that travel through the solution, creating cavitation bubbles. These bubbles start out small, but increase in size and eventually collapse. The collapsing of the bubbles releases high-speed jets of liquid that can remove contaminants from the surface of the object. Ultrasonic cleaning is gentle enough to be used with a wide selection of materials including various metals, glass, and plastics. It is safe for use with parts used in a broad range of industries, including pharmaceuticals, medical devices, automotive parts, and more.

The nature of ultrasonic cleaning itself has many advantages, and these benefits can be further enhanced by selecting the right detergent to use with your unit. A detergent is a surfactant (a surface active agent). It is an amphiphilic molecule that has both a hydrophilic and hydrophobic part. This property means that a detergent will lower the surface tension of a liquid it’s added to. In turn, this helps to weaken the adhesion of contaminants to the surface of objects submersed in the liquid. In an ultrasonic cleaner, the lowered surface tension of the bath fluid also serves to increase the force created by the ultrasonic waves, having a further impact on the cleaning power of the unit.

There are a variety of different types of ultrasonic detergents to choose from. The one you select will depend on several factors including what part you’re cleaning, the material it's made from, and the nature of the contaminants you need to remove. The most commonly used detergents are moderately alkaline solutions, but highly caustic cleaners are ideal in some situations.

There are also specialized cleaners that may be used in specific cases, including acidic detergents or enzymatic solutions. In some cases, it may be necessary to forgo the detergent altogether and simply use deionized water.

Within all those types, you'll find a range of formulations. For example, some solutions contain inhibitors that help protect the material they are cleaning.

Here, we’ll go into a bit more detail about all of the above-mentioned detergents and their use cases.

Most general-use detergents have a pH of 10.0–12.5, which means that they are moderately–highly alkaline. Stronger solutions may contain caustic soda which will increase the alkalinity.

These detergents can work well to remove contaminants such as greases and carbon from the surfaces of metals, glass, ceramics, and plastics, although specific applications can vary depending on the formulation.

We recommend Sonic Power Degreaser for general cleaning. This safe, industry-approved formulation is suitable for a broad range of ultrasonic cleaning applications. It’s non-corrosive and can be used on most metals as well as plastics, composites, glass, and painted surfaces to remove carbon, coolants, dirt, grease, oil, and more.

For more aggressive cleaning, we recommend Sonic Power Degreaser HD. This detergent is ideal for automotive rebuilds and other heavy-duty processes. It’s suitable for use with a range of ferrous and non-ferrous metals, plastics, and composites. We’ve used these products for years and can attest that they work very well for their recommended uses.

Sonic Power Degreaser HD

Sonic Power Degreaser HD

Highly caustic detergents have an extremely high pH (typically 14). These cleaners contain hydroxides (which are highly corrosive) and should be used with care. They are effective at removing rust, grease, and other strongly adhered contaminants. However, they are not compatible with as broad a range of materials as general-use cleaners and should be used with caution. They can damage some metals including magnesium and aluminum, but can usually be used with steel, stainless steel, and cast iron.

We recommend Sonic Power Degreaser HD. While many caustic detergents come in powder form, this is a liquid which makes for safe and easy dilution. This highly caustic cleaner is specially formulated to remove scale, carbon, rust, and other stubborn contaminants.

In some industries, such as food and pharmaceuticals, it can help to use solutions that contain enzymes. These can improve the cleaning properties of the solution by helping to remove organic contaminants from the surfaces of objects. The enzymes serve as catalysts, breaking down the organic materials, such as blood or starches.

The type of enzyme cleaner you use will depend on the contaminant you want to remove. For example, amylase enzymes are suitable for removal of starches and carbohydrates whereas proteolytic enzymes work to remove saliva, blood, and other proteins.

Acidic detergents are those with a low pH. They are useful in certain situations but should be used with caution as the acidic solution could damage objects as well as the cleaner itself. Copper, brass, and aluminum are particularly sensitive to acids. That said, acidic cleaners often contain inhibitors that will protect certain materials from damage.

Common uses for acidic detergents include polishing instruments, cleaning electronic parts, and removing oxides or mineral deposits such as limescale from metals.

We recommend UP 132-B, a mild phosphoric acid solution designed to safely clean at low temperatures. This environmentally-friendly detergent is commonly used on brass instruments but is suitable for many other applications. It’s compatible with copper, aluminum, stainless steel, bronze, plastics, glass, and ceramics.

Looking to get an idea of which solution is best for your particular industry? The table below shows some suggestions for the most compatible chemicals for a given use case. You can browse these solutions on our detergents page.

Still trying to decide which detergent is suitable for your application? Ultrasonic Power experts are on hand to help. Get in touch today to find answers to all your ultrasonics questions.

Main image credit: Andrew Martin