Hi,
We built a railing for a customer in Florida near very near the coast. The powder coat is blistering and we worry that Galvanic Corrosion is the culprit. The railing is made from 6061 Alum (solid rect. bars 1/2"x2" and 3/4"x2"). It is a cable railing (I.e> uses horizontal strands of 316 cable for balusters). The powder coating was done by a professional powder coating firm. They used an epoxy primer(not sure if it was Zinc rich or not) and a polyester top coat. I spoke with the powder coat supplier and they said that mill finish aluminum needs to be deoxidized. I am not sure my powder coater does this or if it is contributing to the problem? It is possible/likely that abrasion from the cable has caused the powder coat to wear through to base metal and there is contact between the 1/8" dia cable strands and the edge of the holes going through the post. Does any one feel this contact would be enough to cause the paint to bubble around the cable holes? Its only been there for 1.5 years.

Thanks in advance to anyone who provides feedback.