If you have ever tried plating over leaded brass, you’ve most likely experienced the dreaded lead soap at some point. So, you may be asking…
What is Lead Soap? It’s just what you’d expect it to be — saponified lead.
How can you tell if you have lead soap? Telltale signs of lead soap include either cloudiness in the deposit or a dark appearance in one particular current density area.
Is Lead Soap Difficult to Clean? You betcha! Metallic soaps are typically difficult to remove from a part’s surface, with lead soap being one of the most stubborn.
How is Lead Soap Formed? Metallic soaps can be formed in the cleaners. As noted in prior cleaning posts (here, here, and here), soak cleaners work by both saponifying and removing soils from a part’s surface. Oftentimes a cleaner is able to saponify the lead, but cannot remove it.
How can you remove lead soap? Acid-containing fluorides are most often used. These fluorides are actually what help remove and prevent further lead soap formation. Occasionally, the acid fails to solve the issue and the cloudiness continues. In cases like this, it may be necessary to increase the fluoride concentration of the acid. It’s also important to ensure that there is no other source of the cloudiness or haze.
Is there a way to eliminate or minimize lead soap in the first place? By using a specifically formulated cleaner, you should be able to minimize the formation of lead soap. Most of these are typically low alkalinity formulations.
Need help? As always, Asterion stands ready to answer your cleaning questions and optimize your operations. For further information, contact us today!