Options for Outdoors
We want to provide more powder coated products for outdoor use, but we do not want to get into zinc phosphate or chrome. Can we achieve good results on steel parts if we use a primer, and if so, how do we need to process the parts?
Q. We want to provide more powder coated products for outdoor use, but we do not want to get into zinc phosphate or chrome. Our powder vendor tells us we can achieve good results on steel parts if we use a primer. Is this true, and how do we need to process the parts? T.G.
A. Outdoor performance is related to a total process, not just one aspect of the process. Zinc phosphate or other metal treatments can add a lot to the corrosion resistance of a metal when combined with the right powder at the right thickness. Without that additional corrosion protection from a metal treatment, it is necessary to increase performance of the powder itself by addition of a corrosion-resistant primer. A steel surface that is blasted makes a good surface for bonding. Blasting should include a grit to make sure that the surface is cut. Blasting the surface with shot only and no cleaning and phosphating after is risky, because the spherical shot will not remove organic soils. A good epoxy primer should be applied and then partially cured before the UV-resistant topcoat is applied. The topcoat will help with moisture and sunlight resistance. The primer also will provide excellent moisture resistance. So the answer to your questions is yes, a powder primer and topcoat can work very well for outdoor applications on steel.
One note, this is not as reliable a process for non-ferrous metals, especially aluminum. Aluminum surfaces that will be exposed to outdoor environments should always have a conversion coating applied to make sure that the surface does not oxidize and de-bond the coating.
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.
Powder coating is one of the most durable finishes that can be applied to industrial manufactured products, and offers excellent corrosion protection and is very safe because of its lack of volatile organic compounds.
Masking is employed in most any metal finishing operation where only a specifically defined area of the surface of a part must be exposed to a process. Conversely, masking may be employed on a surface where treatment is either not required or must be avoided. This article covers the many aspects of masking for metal finishing, including applications, methods and the various types of masking employed.