Powder coating doesn't prevent rusting?
Powder coating doesn't prevent rusting?
(OP)
Hello guys! I need to know something about powder coating. I have been reading about powder coating for corrosion protection. I had this thought in mind that powder coating basically helps prevents all sorts of corrosion, especially rusting. Recently, I read in an article that powder coating won't prevent rusting and something else is required to do that. Is that true? Is there any method we can try to improve the powder coating to prevent rusting?





RE: Powder coating doesn't prevent rusting?
However- if you have articles made out of hollow sections, there's an interior surface to worry about. Then there's damage of the coating- anywhere bare metal is exposed or the coating comes disbanded from the substrate, the substrate will corrode and the corrosion will mine under the nearby coating causing it to lose adhesion.
Powder coatings tend to go on bare or phosphated steel surfaces. I don't recall if they remain adherent over a zinc plated surface or a hot dipped galvanized surface. Zinc plating or galvanizing can give you additional protection by acting as a sacrificial anode to protect the metal on interior uncoated surfaces or at places where the powder coat is locally damaged.
RE: Powder coating doesn't prevent rusting?
http://www.gattoplaters.com/overcoming-outgassing-...
RE: Powder coating doesn't prevent rusting?
The epoxies offer excellent corrosion and solvent resistance but have comparatively poor gloss retention in sun, tending to go chalky. The polyesters are the opposite.
We use polyester powder coatings on top of phosphate washed new steel for guardrails and find that it gives excellent corrosion resistance and gloss retention in that service.
RE: Powder coating doesn't prevent rusting?
So you have to be able to assemble the product completely with no scars and cuts, or make due with lousy hand-repainting. So a handrail, for example, can be powder coated, shipped back to the site, then bolted in. It will last pretty well if not scarred or broken. And most handrails do pretty well for many years. Not forever though.
A rail near a truck ramp or a forklift area is going to get scarred quickly. If painted, it can be repainted. If powder-coated, it will rust quickly at every scar or cut.
If you have a assembly item, recognize the powder coat is very think, and will vary in thickness considerably like a very thick, very sloppy coat of paint. So it will cause problems shutting lids tightly or bolting on later parts in the assembly.. get it on the wrong surface, and you have rub off or scarf off the powder coat to get the "flat surface" again. Ugly and bad-looking, source for later rust obviously. If you have a assembly part exterior, then you have to either shield the inside from the powder coat and heat somehow.
Obviously, you can't powder coat a watch, a car door, or anything with pieces that can't stand the oven temperature.