Preventing Foaming in your Aqueous Parts Washer

sponge with foam cleaning aqueous washer

Table of Contents

Although it looks fun in movies, bubbles rushing out of your industrial parts washer and onto your manufacturing floor is more of a workday disaster and poses a safety hazard. There are several reasons you may be dealing with a surplus of foam, such as:  

  1. Improper water temperature – an incorrect water temperature can lead to excessive foam buildup. Most aqueous detergents foam if the water temperature is below 120 F.  
  2. Excessive oil and grime – excessive oil and dirt, fats, and natural oils, especially when there’s a lot, can cause foaming. Defoamers cannot combat foaming when your chemistry is over-saturated with oils, soil, fats, and other contaminants. 
  3. The incorrect ratio of detergent to water – it is imperative that your soap-to-water ratio is correct. More soap and less water will leave you with a concentration that will cause foam. Certain aqueous detergents will foam when there is too little detergent in your washer’s tank. 

Why is it a problem? 

Excessive foaming is a problem for a few reasons. Foam is not caused by the mechanics of the parts washer but rather by your run temperature, chemical concentration, or contaminants removing the parts washing. Foam on the floor means less detergent in your wash tank, reducing cleaning power. More importantly, foam on the floor is a hazard, causing injuries.  


Foam is a common problem when using aqueous cleaners, and while defoamers can be added to your cleaning solution, that is only a temporary fix for the problem. Yet, this doesn’t mean you’ll forever have to deal with foam on your floor. Here are some tips to keep your floor foam-free:  

  1. Adjust the temperature. Obtain your chemistry’s SDS and check for the recommended temperature. Run your washer at the lowest temperature. Cold water holds more dissolved gas bubbles. With fewer gas bubbles, soap has less to bind to foam. Finally, titrate your parts washer to ensure your chemical concentrations are in line with SDS. 
  2. Be sure to tell your Application Engineer if you are removing grease or lubricants with animal fat content or vegetable oils. There are several ways to combat foaming. First, tell your Applications Engineer if you are removing grease or lubricants with animal fat content or vegetable oils. These types of contaminants are common in stamping and bearing washing applications. If this is the case, you will need to increase the wash and rinse run temperatures in your parts washer to be above 170-180 F.
  3. Pre-clean your parts. While this may seem like it defeats the purpose of having an industrial washer, it’s an excellent way to prevent foaming. You can pre-clean your parts by wiping excess oils and dirt from them before washing them. Additionally, with modular washers, you can pre-clean by running your parts through a heated rinse cycle before introducing your cleaning agent.

For more information about aqueous parts washer detergent foaming, submit a form on our Contact Us page.



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