Ask the Expert Question-and-Answer Archive

by Ron Joseph

May, 2009

Corrosion Protection

Q. We are painting a Steel Frame using MIL-C-53039 CARC Paint over Powder Coated Primer. This Frame is being used in a Coastal Area, and needs ultimate corrosion protection.

Can you comment on this Procedure above,or recommend a better paint process?

A. I'm not entirely sure this coating system will stand up to the elements for a long period .. 10 years, or so. It depends on many factors; surface preparation, type of powder coating primer, film thickness of MIL-C-53039. The most vulnerable areas where corrosion is most likely to take place are at the edges of the frame. I suggest you pay special attention to these areas. Also, I don't understand why you are applying a powder coating primer and a liquid topcoat. Perhaps you intend to apply the primer in a shop and the topcoat on-site? If so, you will need to be especially careful to prepare properly the primer before applying the topcoat.

Will you be welding the frame after applying the powder coating primer? If so, the welds will be the most vulnerable areas for corrosion. The bulk for the frame might stand up well to the environment, but unless the welds are properly prepared and protected, corrosion will likely take place in these areas.

I don't know how large this project is, but if you would like me to assist you with this project on a consulting basis, please don't hesitate to get back to me.

Regards,

Ron Joseph