Roughen up the steel GOOD with some coarse sandpaper to give the paint something to grab onto. Those thin coats build a finish that won't chip or peel like one gloopy mess always does. Let each coat dry completely, even if it takes all day, because rushing ruins everything. That patience makes a finish so durable it feels like part of the metal itself. Purists can complain, but a tough, beautiful chair speaks for itself.