Powder Coating Info

[Peter Pleitner]

Hi Jim Well said! I've used powder coating for quite some time now, but applied professionally by a gear head ( X - GM proving grounds) not a production shop or "decorator". As I recall there are epoxy, polyester and urethane products. Epoxy breaks down with exposure to UV rays, and urethanes I believe are more brittle than polyesters, but naturally brittleness is also a function of thickness. This gear head is looking at semi retirement and will soon publish a thin manual for consumers. I'll post info on it when its available. And Bob Thomas was right on! - pity though he doesn't sign his opinion. Alan Campbell has a point though about hiding fatigue cracks. I've known experts preparing long distance rally car to use cheap white paint on suspension members and welds for exactly that reason - to reveal cracks ASAP. Cheers, Peter -----Original Message----- From: Chase, Jim [mailto:Jim.Chase@fuelsubsea.com] Sent: Monday, April 30, 2001 7:01 AM To: mg-tabc@yahoogroups.com Subject: [mg-tabc] Powder Coating Can anyone provide a suitable specification for powder coating of chassis components and wire wheels? I am not surprised at the widely differing experiences of people with regard to powder coated or paint finishes. There have been lots of references to powder coating but no one has even mentioned what material they are referring to let alone the procedures used to prepare the surface and apply the material. I don't think the issue is whether powder coating is better than paint coating but which powder coating or which paint finish to use and how should it be prepared and applied. I had a chassis powder coated. In complete ignorance I asked for black gloss powder coating. What I got was the chassis degreased, grit blasted, phosphate treated and polyester powder coated. The result appears similar to a paint finish and is tough, flexible and chip resistant. You can drop a spanner on it without any damage. I then had some other chassis components powder coated at a different contractor because they were a lot closer to home. This time the contractor degreased, grit blasted, chromate treated and powder coated the parts. However I have no idea what type of powder was used. I need to go back and ask so that I can avoid it in future. The results looked very similar to the previous powder coating but the coating chips very easily. Powder coating can be done using a wide range of materials including:- Polyester, nylon and epoxy resins to name but a few. No doubt the resulting coating can vary as widely as the properties of the materials used. Just like with solvent based paints. I am sure that degreasing abrasive blasting and some form of surface conversion treatment (phosphate or chromate) are necessary for successful results with powder coating, just as they are with a solvent based paint finish. As for solvent base paints giving evidence of rusting of the underlying surface. I have experience of a boat trailer painted with hammerite enamel where the metal corroded away under the paint just behind the tow hitch. By the time the paint started to blister there was more paint than metal holding the tow hitch to the trailer. I am reminded of a saying that a good coat of paint can hide a multitude of sins. Regards Jim Chase Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/