Stainless steel, with its sleek surface that resists corrosion and wipes spotlessly clean, is a favorite in every kitchen and a vital component in many industries, including the medical supply field. Some metals are paintable with minimum preparation, but stainless steel is not one of them. Manufactured from iron alloy combined with chromium, the surface of stainless steel is impervious and non-porous. Paint won’t stick without sufficient preparation.
Prepping the Surface
For paint to adhere, you must first dull the surface of the stainless steel. The two methods for doing this are:
- physical abrasion
- chemical etching
Physical abrasion, through sanding or blasting, is the safest method for do-it-yourselfers. You can sand by hand or with a power sander, using 400-grit sandpaper. For numerous stainless steel items, such as hardware, it might be worth renting a blaster and using silicon abrasive particulates to abrade the glossy surfaces. Avoid blasting with metallic particulates, which can cause the steel to rust once the protective layer is gone.
Chemical etching involves applying an acidic solution that cuts through the smooth surface of the stainless steel, dulling it to the point where paint will adhere.
Also called “pickling,” the chemicals used to etch the steel surface are highly acidic and produce hazardous waste, making etching unsuitable for most home projects.
Cleaning and Priming
After removing stainless steel’s glossy anodized surface, clean and prime the metal as soon as possible to avoid rust development. Wash the steel surface with a good degreasing detergent or solvent. After the surface dries completely, apply a rust-inhibiting wash primer, which will protect the steel from corrosion.
Depending on your item’s features and the desired surface texture, you can brush, spray or roll on the new paint. Once correctly primed, the surface can accept virtually any type of paint, depending on the look you're going for. If the item will be outdoors, use an exterior paint. The key to a professional-looking finish is to apply multiple thin layers of paint, allowing each layer to dry completely before applying the next. Spraying typically offers a smoother surface than brushing or rolling.
For an ultra-smooth finish coat without spraying, brush on a two-part epoxy paint. Epoxies require careful mixing and application, but they offer high-quality gloss and semi-gloss coatings that stand up to household cleaners and frequent wiping.