Issue link: https://www.e-digitaleditions.com/i/1014893
in what you can do. If any readers have suggestions, I will be glad to pass them on. However, I suspect that if someone has figured out a method, they will keep it to themselves. —G.T. Testing adhesion on powder coating Q What's the best method for testing adhesion on pow- der coating? M.K., Iron Mountain, Mich. A The best and most accepted method for testing coating adhesion is the crosshatch adhesion method described in Amer- ican Society for Testing and Materi- als (ASTM) D3359. Of course, this is a destructive test, meaning you will ruin your part. So test it on a hidden area or on a test panel on similar substrate processed alongside your actual part. —N.L. Powder coating chrome parts Q Do you have any informa- tion on powder coating over c h r o m e , f o r e x a m p l e , wheels, bike frames, and so on, in refer- ence to adhesion, appearance, and lon- gevity? We have customers calling for it but don't know much about the process of powder coating over chrome. Thanks. A.J., Anaheim, Calif. A Any paint over chrome is ask- ing for problems. Actually, just one big problem: Lack of adhesion. Scuffing the surface of the chrome will give you a chance, but I sure wouldn't want to make any prom- ises to a customer about how long it will last. You don't know how your customer will treat the part. If a break occurs in the powder-coated surface, it will open a huge door for the start of peeling. Some chemicals are available that will enhance adhesion, but I don't know how they react and how much good they really do. You can do this, but don't make any guarantees. —G.T. Turning parts in a rotisserie to prevent sagging powder coating Q We have a customer who wants 40+ mils of PVDF (polyvinylidene fluoride) on his valve bodies. We're having a lot of problems with sagging during the final stages of the operation. I was wondering if anyone makes a rotisserie that will turn these valve bodies while they're in the oven? P.T., Parkersburg, W.Va. A I'm sorry, but I've never seen such a device before. How- ever, I have seen companies design such devices for their own purposes. It probably has a lot to do with the limited market potential of such devices. —N.L. PC Editor's note For further reading on the problems discussed in this column, visit Powder Coating magazine's website at www. pcoating.com and search the Article Archive by subject category. All articles listed in the archive are available for free download to registered users. G e o r g e R . T r i g g i s p r e s i d e n t o f G R T Engineering, Prospect, O h i o . H e h a s b e e n involved in the powder coating industry for more than 40 years. H e h o l d s a B S B A degree from Muskingum College, New Concord, Ohio. Nick Liberto is presi- dent of Powder Coat- i n g C o n s u l t a n t s (PCC), a division of Ninan, Inc., 1529 Lau- rel Ave., Bridgeport, CT 06604. Established in 1988, PCC is an independent engineering firm specializ- ing in the use of powder coating technol- ogy. Nick has more than 3 decades of experience in the powder coating indus- try and is a member of many industry associations, including the Application Equipment Technical Committee of the Powder Coating Institute. A registered professional engineer in Connecticut, he holds a bachelor's of science degree in mechanical engineering with a minor in physics. He can be contacted at 203/366-7244; email pcc@powdercoat. com; website www.powdercc.com. degree from Muskingum College, New (PCC), a division of independent engineering firm specializ- POWDER COATING, August 2018 29