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Issue link: https://pf.epubxp.com/i/100758
po wd ercoa tin g C L I N IC n Film Thickness Tolerance Q. I have a customer who is asking for products to be powder coated within a range of 80-90 micron thickness. The best I can get is between 70 and 90 micron. Is the tolerance they are asking for possible? A range of ��5 micron seems too tight for me. R.S. a. You will probably not be able to hold that tight of a flm thickness tolerance. If you have fat parts that are easy to coat, you can probably hold ��12 micron with great care during application, perfect earth ground and a good powder. If the part has geometry that is harder to coat, the tolerance will defnitely be more diffcult and flm thickness variation will be greater. Concentrate on consistent application technique, consistent gun-to-target distance and smooth fow. You should be able to establish a consistent range of 70 to 90, but no tighter. n PreTreaTmenT oPTions Q. Are you aware of any uncomplicated, user-friendly pretreatments that are compatible with powder coating, will inhibit rust on surfaces with deep inset corrosion and will accelerate beneath the coating after the process is complete? J.R. a. Iron phosphate works well with powder but has modest corrosion resistance if the coating is broken. Zirconium oxide products can be modestly better, and some contain other metals such as copper or titanium and are somewhat more resistant to oxidation. Zinc phosphate has very good corrosion resistance, but it also requires waste treatment and would not be considered simple or user-friendly. One of the best options is a primer. Thoroughly clean the surface by chemical or mechanical cleaning, then you can have the parts electrocoated or you can apply a powder primer. The primer provides exceptional resistance to moisture penetration and a thicker flm with better edge coverage. The primer does a great job of stopping the undercoat creep you refer to. pfonline.com/experts n Powder coaTing���s FuTure Q. There for a time, powder coating shops were popping up on every corner. Now it seems everyone has figured out that margins are extremely tight and that powder coating is not as easy as the guys who sell it (at roughly triple the price I paid just a few years ago) might like for you to believe. What do you think the future holds for powder coaters? In an American economy where manufacturing seems to have left or to be leaving, can you offer a little hope for those of us still in the trenches? J.D. a. First of all, I am surprised that you characterize the cost of powder as triple what you paid not long ago. In 2005, the average price for a pound of powder in North America was $2.50. In 2011, the average price per pound was $2.63. Maybe you are using some high-cost products in low volume? Anyway, the price has gone up based on the increases in raw materials, so I understand that is a pressure on your business. As far as manufacturing leaving, that has been an issue for some time now. However, manufacturing in the U.S. is alive, and some sectors are growing. In the past several years, I have worked on several large projects where U.S. manufacturing was adding on or bringing in work from other countries. The demand is there, but there is still pressure on manufacturing from foreign competition and from the trend of investment dollars increasingly being funneled into fnancial instruments instead of building. Still, powder and equipment suppliers are busy, and manufacturing is playing a steady role in the gradual improvement in our economy. The Institute for Supply Management reported that manufacturing grew in October for the second straight month. The previous three months had shown some contraction, but prior to that economic activity in the manufacturing sector had expanded for 34 straight months, and overall economic activity had expanded for 41 straight months. As far as an individual coater is concerned, the overall picture is less critical than some personal experience. I suggest you keep up the good effort. Work with your suppliers if powder cost is too high, or fnd new suppliers if that is possible. Test powders to see what works best by cost per applied square foot, not cost per pound. Work on effciency and look for waste. Look for service too. Selling is only part of the job; you need support to help you be your best. Work on application effciency and get involved with associations and events that help you expand and build connections. Check out the Powder Coating Institute and consider becoming a custom coater member. Look at the Chemical Coaters Association International and see if there are opportunities for edu- RODGER TALBERT, Technical Contributor, powdercoating@pfonline.com 52 JanUaRY 2013