Parker Ionics Regional Sales Manager, Mike Nugent, recently responded to a question from a powder coater in Vietnam, that’s having issues with coating in the extreme humidity. Many of us have experience changes or have difficulties coating in the hot, humid summer months. Here’s some great points to address in your powder coating facility during this type of climate condition.
Mike Nugent responding to a questions posed on “The Powder Coating Network” on Linkedin: “The short answer is you need to control the powder storage and application areas for temp and humidity. Recommended temps at 70-80F @ 55% RH. Check with CCAI (Chemical Coaters Association) & PCI (Powder Coating Institute) handbooks or any number of other references. Powder is hygroscopic and will absorb all the moisture you allow. Humidity, both extreme dry and above the recommended 55% will adversely affect the ability to charge powder and the charged particles ability to retain the charge.
High heat and humidity may also adversely affect impact fusion and powder build-up along the walls of the powder passageways through the gun, diminishing the ability to frictionally charge and transfer electrons from the gun tube walls to powder. You may also be experiencing increased gun/pump/injector maintenance issues, impact fusion, surging, etc. Powder handling properties are also affected by temp & humidity, adding to variability of application.
Corona charging applicators are affected by heat & humidity as well, but Tribo is more susceptible to environment and powder formulation.
In order to control these and other variables an environmental room encompassing the powder application, collection, reclaim and storage areas is recommended.
There are no effective post-blend powder additives for high humidity conditions. However, there are known post-blend additives the powder manufacturer adds during production to enhance powders ability to tribo-charge. Did you recently change batches of powder? You might want to check with your powder supplier to assure something didn’t change on the batch ticket.
With the high humidity and increased temps your compressed air dryers, oil removal and particulate filters are getting a work out. Make sure all drains and dryers are operating properly. The compressed air MUST be clean, dry and oil aerosol free.
Another question for you: Do you have excellent earth ground? Do you know where your “earth ground” is located? Can you identify all contact points and know resistance values?”
Great tips for anyone having trouble powder coating in hot humid conditions anywhere in the world. Thanks Mike!
Mike can be contacted at: email@example.com