What is the best way to prepare a new galvanized metal building to be painted ?
In order to prepare for painting, you first have to use an alkaline cleanser solution to wash the steel. Next, use an even, gentle stroke and some sandpaper to rub the steel down. Get rid of any debris/dust using a clean cloth. Check out http://www.ehow.com/how_4886646_prepare-galvanized-steel-painting.html for details.
Galvanization that is 48hrs- 2 yrs. old is considered "partially weathered galvanized steel"You will need to remove the oxidization for paint adhesion. http://www.galvanizeit.org/about-hot-dip-galvanizing/what-is-hot-dip-galvanizing/the-hdg-coating/enhancements/painting-hot-dip-galvanized-steel/