Painting over anodize?

Is any special preparation require when painting over a newly oxidized steel surface?
Will either fine roughing up with 400 grit work, or using a regular oxide
primer?
Or...?
Thanks.
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Your question is far too vague, but painting steel is not rocket science. However, here are some rules. Don't paint over mill scale or rust. If the steel has not been shot blasted, it still has mill scale on it and that will lift on its own, so it must be removed. Wire brushing and grinding is slow and ineffective for this. Sand and shot blasting to white metal is much better. Purpose rusting helps to lift the mill scale and makes blasting faster. If rust exists and cannot be removed. The use of muratic acid works well. If that cannot be used, then it can be converted with converters. In the case of chemical use, the chemicals need to be washed away with water and neutralized with a soda and then washed again. After all of these processes, you have a short window of time to get the first coat of etching primer applied before corrosion sets in. Depending on prevailing conditions, that window is between 20 minutes and 2 hours. Whatever paint system you elect to use, you must follow the manufacturer's directions verbatim. Do not take short cuts. The first paint applied is critical to the paint scheme being applied and all the other ones which may occur later on. You probably think I'm really anal about this and well over the top. I am not. Take short cuts and you will learn the hard way. Many times these rules are not followed, but only in the cases where the failure will occur on some one else's dime or ignorance is present.. Steve

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Confirmed: sanding these parts 24 hours after spraying 2nd coat and the paint is not dry. Gummed up the sand paper.
Boy, does this Rustoleum paint dry slowly... It says 48 hours, but at this rate it looks like it will be longer.
Is Krylon a better choice? Or...?
Thanks.
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Rustoleum is good paint. There are other heavy-duty enamels, from the majors, but most straight alkyds are going to take a long time to dry hard. That's just enamel. Rustoleum probably is slower to dry than most. In many applications, they don't use a second coat. It's better to use a good primer, and then the top coat will lay on a lot thicker than each coat used without primer. Get a compatible primer made for use with the enamel.
There are a lot of industrial-type paint systems out there today, including several polyurethane systems that are tough and that produce a nice finish. Probably the toughest is two-part polyurethane, which comes in brushable versions. Don't touch the spray-coat versions unless you study it well. It's highly toxic and you can't protect yourself with just a respirator. But the brush-on is safe.
I like plain, old-fashioned enamel. But I use it with primer.
-- Ed Huntress
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On Tue, 1 Sep 2009 19:23:25 -0700, Ed Huntress wrote

It's odd: same series Rustoleum paint, one flat white, one gloss "internationsl" orange.
The flat white dries very quickly. I've applied additional coats as quickly as 1, 3, 4, 6 hours without sanding, with no evidence of wrinkling.
The gloss orange, on the other hand, is 72 hours and counting, with no evidence of complete drying. It is still possible to dig in a thumbnail and see its impression. (This is outdoors in 80 degrees with pretty low humidity.)
I think I'll strip and try Krylon, or an automotive paint supplier's enamel in a Harbor Freight DIY spray can. The Rustoleum is going back to Orchard Supply.
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Yet another thing I've done, on electrical enclosures that had to look real spiffy, is to buy a case of beer for the guy at the local body shop and have him paint it for me. No muss, no fuss, no respirator, and a damned good job.
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