| 1 MINUTE READ

Pinholes in Powder Finish

Share

Facebook Share Icon LinkedIn Share Icon Twitter Share Icon Share by EMail icon Print Icon

Q. We apply powder coating on aluminum panels, and are facing a problem with pinholes. Our pretreatment is acid etching and chrome-free coating. Please give me a solution for the pinhole problem. D.K.

A. The pinholes could be from several sources:

  • The metal surface: The aluminum could have porosity or fractures that are outgassing.
  • The treatment: The treatment process could be leaving some contamination on the part surface.
  • The powder: The powder may be defective or it may be applied too thickly.
  • People: Someone may have lotion or something on their hands that is getting onto the parts.

To find the problem you will need to work through a process of elimination. Do you bend or weld the aluminum? If so, are the pinholes located around the bend or the weld? If it is around a stressed area in the metal, that could be the source of the problem. Try the same powder on a different source of aluminum and coat those parts on your line. Have some parts treated by another facility and coat them on your line. If the problem goes away, you will know it is your pretreatment. Treat the aluminum at your plant and coat it in a different location. Try a different powder and try applying the powder thinner. You should be able to find the problem by systematically eliminating different sources. 

RELATED CONTENT

  • Understanding Fluidized Bed Powder Coating

    For more than 50 years, fluidized beds have been used to coat parts with powder coatings. In this article, two industry experts tackle some common questions about the fluidized bed process…

  • Anodizing Vs. Powder Coat

    I am an engineer on a large yacht build project and urgently need information and advice on choosing a finish for the aluminum deck plates in the engine room.

  • Understanding Infrared Curing

    Infrared cure is gaining increased attention from coaters as a result of shorter cure cycles and the possibility of smaller floor space requirements when compared to convection oven curing.