Help: Targa bar primer adhesion problem

[steve84]

I've removed my Targa bar cover, used a stripper to remove most of the black paint, and wet sanded to remove the rest. Today, I cleaned it with thinner and dried off with paper towels. I then sprayed a thin coat of Wurth self-etching primer in the basement of the pool house (relatively high humidity), and then brought it upstairs to dry (lower humidity). After about half hour, I went to check on it and found that in certain spots, the primer was chipping off with no adhesion of any primer to the bare bar. The location of this chipping is limited to the front vertical surface with the screw holes, but only in a few spots. There is no such chipping on any other surface of the Targa bar. This leads me to believe that the chipping is not due to the humidity present while spraying.

Any thoughts about the cause of this chipping or, more importantly, how to get the primer to stick to the Targa bar at those spots?

Thanks,

Steve

[timmy2]

Usually it's a problem with a layer of dirt or something on the metal that stops adhesion.
Try sanding and really cleaning the problem areas and hit them with primer again.

[Michael T]

It is likely the high humidity when the primer was sprayed. I live in Houston and after two attempts in June and then August, the humidity was just too high. When I waited to October and got a lower humidity and temperature, it looked great. No change in technique.

[Justin@Athens]

Any residue left from the acetone would cause this. Because you mention that is in select locations, along the same surface, this leads me to believe you may have simply neglected to wipe down this area as well as the rest of the piece.

[porwolf]

I never painted a Targa bar but I have some experience with 2 component epoxy. Maybe you could strip the bar again, new paint should come off easily, clean sand paper the front edge thoroughly and brush on regular epoxy. Epoxy really adheres well to stainless steel, especially when it is not a smooth surface. After the epoxy cures you could sand that smooth and apply regular paint. Like I said, I have not done that, just a thought.

[Reiver]

Have you thought about getting a wrap on it? It seems that particular piece would be easy and low maint.

[RSTarga]

powdercoat is the most durable.

[steve84]

All: Thank you for your prompt and helpful responses. This morning, I removed all of the primer by wet sanding. Then I wiped down with thinner and dried and then cleaned again with Clorox wet wipes for stainless steel and dried, and then dried in sun. Applied a coat of primer on back lawn in the sun and then placed in pool house to dry. After two hours, the primer adhered in all locations. Thank you again.

Steve