Separate and Different Cleaning Baths Bring Best Results

“Why can’t I use the same bath for both soak cleaning and electrocleaning?” is a question that is often asked, but rarely addressed with one definitive answer. To do so, would be putting your plating line in peril.

Sure, sometimes you can employ the same bath for both, but this is seldom an acceptable answer. Other times you can use the same chemistry, but in different concentrations in separate tanks. However, most often dedicated tanks with different soak cleaner and electrocleaner chemistries are required. Here’s why…

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The soak cleaner’s job is to remove excess oils and easy-to-clean dirt and grime. Think of the soak cleaner as the part of your sink where you sit dishes in soapy water before scrubbing. The soak cleaner typically is lower in alkalinity than the electrocleaner, but possesses a higher concentration of surfactants. Higher surfactants allow the soak cleaner to saponify and remove oils and grime from the part’s surface. Much like our dishes at home, it will not remove “stuck on stuff,” but prepares the part surface for subsequent scrubbing.

Consider the electrocleaner the “muscle” of the cleaning operation. Its mandate is to scrub away any remaining stubborn soil and other debris. Typically, an electrocleaner is operated so that the parts act as if they were anodes, whereas oxygen gas is produced when under current. The oxygen bubbles that are generated do a nice job of scrubbing the surface clean as they make their way to the top of the bath, removing the remaining oil and grime along the way. It is important to note that electrocleaners require more alkalinity than soak cleaners. The alkalinity is primarily what allows the electrocleaners to pass current through the solution, which prevents the parts from “burning” (e.g. roughness around the edges).

So…why can’t we do both in the same bath?

  • It is a fact of chemistry that only so much “stuff” can be in a solution at one time. The exact amount is predicated on the temperature of the solution, the solvent (in almost all plating applications this means water), and the solutes (what we wish to retain in the solution).
  • If we attempt to make one bath act as both the soak cleaner and the electrocleaner, we are asking it to tolerate the same soil loading as two baths. As you might imagine, this will result in an extremely short bath life.
  • The soak cleaner needs more surfactants than the electrocleaner and the electrocleaner needs more alkalinity than the soak. To run one bath as both, demands high alkalinity and high surfactant concentrations. Such a combination significantly lowers the amount of soil that can be pulled into the solution and off the part surface.

In closing, it is always best practice to have separate soak and electrocleaner tanks. Doing so will not only provide extended bath life, but will ensure optimum cleaning of parts. The actual chemistry used to perform each cleaning process is typically different, with some exceptions. As always, Asterion is ready to support your cleaner selection and operation.