Painted furniture, especially pieces that get hard use or are in high-traffic areas where they might get bumped or scraped, can be protected with a topcoat of sealant. Regular latex paint dries to a hard finish you can wipe clean. But delicate painted detail work benefits from an extra protective topcoat to prevent surface scratches, limit signs of wear, and cause spilled liquids to bead on the surface for easy mop-ups. Three commonly used types of sealant could give you the extra protection you need.
Paste wax is the most labor-intensive sealant but gives a rich luster to painted work and works for chalk paint as well as other water- and oil-based paints. Typically, you apply the wax in a thin layer on a fully cured painted surface; let it dry according to directions, and then hand-buff until the piece gleams. Look for clear wax to avoid any yellowing -- you can find tinted wax that works like an antiquing glaze, adding a hint of brown patina that "ages" the finish. Some paste wax is made with traditional beeswax, a green product, but most wax is a mix of solvents and synthetic waxes. Check that the wax you select is compatible with the paint finish on the piece to be sealed.
Polyurethane's Dirty Little Secret
Polyurethane is a solid performer -- easy to apply, works over most painted surfaces, delivers a reliable shine and a hard protective finish that lasts, even under tough use. Polyurethane lets you wipe up coffee rings, causes most liquid to bead so you avoid stains, won't dent or dull easily, and it's hard enough to deflect scratches and nicks. But it can yellow over time -- oil-based polyurethane actually imparts a warm glow to the finish. That makes it a risky choice for light- or white-painted wood. If you want a mellow, aged look, the yellowing might work for your style. Increase your odds for clarity by using polyurethane marked "non-yellowing." Spray polyurethane won't leave brush strokes, but multiple thin layers, brushed or sprayed on and allowed to dry between applications, are always better -- and better-looking -- than a single thick coat.
Glossy, Glassy Polycrylic
Polycrylic is a fortified water-based polyurethane that dries to a hard, glass-like finish and is formulated expressly to stay clear. It comes in a low-gloss and high-gloss so you can control the shine. Polycrylic dries very quickly; you get no second chances to rework it as you apply. Using a synthetic brush helps to avoid brush marks -- a spray, applied in light coats in a well-ventilated, dust-free space, is another choice for a good, clean application. Polycrylic may be used safely over most paints; check both polycrylic and paint labels to be sure you have a compatible match.