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Powder Coating

2002

I have a few questions regarding a powder coated fence:

1. Will a continuous spray from lawn sprinklers with hard water cause a powder coat finish to degrade or the steel underneath to rust?

2. Will a continuous spray from lawn sprinklers with hard water cause welded joints that are powder coated to rust?

3. Is it a correct assumption that the steel and joints will not rust? Is the powder coat a barrier from the water?

Lee J. Andrews
contractors - Phoenix, Arizona, USA

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First of two simultaneous responses --

Lee,

In part your assumption is correct, powder coating will protect the substrate from water ... if .... the cleaning and pre-treatment of the substrate is correct and the application and curing of the powder coating is correct and finally if the right powder coating chemistry is used.

Drew Devlin
- Lincolnshire
2002

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Second of two simultaneous responses -- 2002

Hi Lee,

1. Quite possibly, yes.
2. Quite possibly, yes.
3. No, it is a bad assumption. Yes, powder coatings act as a barrier, but only in limited fashion.

George Gorecki
- Naperville, Illinois

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And, yes, usually the weld area will be attacked first, both because it is a bit harder to pretreat and coat, and because the stresses make the weld area electrochemically anodic to the rest of the metal.

Ted Mooney, P.E.
Striving to live Aloha
(Ted can offer longterm or instant help)
finishing.com - Pine Beach, New Jersey
2002

Your finish is dependent on the pretreatment process. Blasting of the welds and a iron phosphate pretreatment will extend your life product life.

Steve Mossige
- Dallas, Texas
2002

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