Powder Coating Aluminum Extrusions
Q. I am a manager for a company that does liquid painting of aluminum extrusions on a vertical paint line using electrostatic discs and painting with high solids polyesters. I have two questions about powder coating of aluminum extrusions. 1) We have been told by some of our customers that they can buy powder coated products at cheaper prices than our liquid painted products. How do powder coaters paint for less than liquid paint? Is it labor, better transfer efficiency? What? 2) Which is better, at high volume production, a vertical line, or a horizontal line?
We are in the process of making strategic decisions for our future, and this information could be very valuable to us. Thanks for your answers. M.F.
A. First of all, powder is not always less costly than liquid. It depends on what liquid paint you are comparing the powder with and the other details of the process. Powder can be very economical because it is a one-coat process and the overspray can be reclaimed for and used. Many liquid systems use a primer and the overspray is lost. An efficient powder coating line with reclaim capability will often be less costly per applied square foot than liquid paint.
On the second question, it’s hard to say for certain without knowing some details, especially the lengths of the extrusions you run. For very long parts, say around 24 ft long, a vertical system is usually more effective because the parts can be packed together very densely and the overall system footprint is much smaller. The tooling is very simple and the coating quality if very high in a vertical system. For smaller lengths and volumes it may be better to use a horizontal system.
This alternative to TGIC-based polyester powder coatings offers similar performance and enhanced transfer efficiencies.
What is right for the customer?
Question: I’ve been told that a powder coated part cannot be “touched-up.” I have some patio furniture that I had powder coated and the powder coating shop that did the work for me stripped the threads in holes used to rack the part.