As with any other painting job, preparation is the key to success. Soap, oil, glue or any foreign residue should be cleaned with an appropriate solvent before proceeding. Remove any rust spots with a wire brush before sanding. Use a fine-grade wet/dry sandpaper to scuff the entire surface. New paint will not adhere properly to the smooth finish on a metal bathroom partition.
Any scratches or flaking paint should be removed and the edges feathered. You should be able to run your hand over the entire surface of the panel without feeling any bumps or dips. Paint will highlight rather than cover surface irregularities.
When the surface is smooth, remove all dust with a tack cloth before painting.
If you don't plan to disassemble the panels for painting, mask any hardware that is not already painted. Paint will not adhere well to stainless or galvanized steel connectors. Masking them before you paint will ease cleanup.
The walls should also be masked if you intend to apply the paint with a spray gun or can.
Appliance paint will work well for this application. It is specially formulated to adhere well to steel. Properly applied, it provides a smooth surface that is washable and stain-resistant.
Enamel paints will work well and adhere to a properly prepared surface.
Latex paints should be avoided. Latex paint is more easily removed from a metal surface after drying and lacks the durability of enamel.
A spray application will give the best results. Properly done, it will leave a surface without brush marks, bubbles or other artifacts associated with brushing or rolling.
If other considerations make spraying impractical, a high-quality bristle brush should be used. Always follow the manufacturer's recommendations for thinning, application and cleanup.
Removing and disassembling the partitions before preparation and painting will give the best results. If this is not practical, supply adequate ventilation to the work area and use breathing protection. A particle mask should be worn while sanding and a solvent or VOC mask should be worn while painting.