On Sun, 30 Aug 2009 14:29:57 -0700, "Steve Lusardi"
wrote:

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.

Use of a passivating metal treatment will extend the window
considerably and will also aid wetting and adhesion significantly.