Painting a folding stool is a good way to cover scratches and dings. You need spray primer, spray paint, plastic, tape, a sanding sponge, a drop cloth, a dust mask, safety glasses and a brush.
Gather your materials outside
Gather your materials and find a place to work outside. Working outside prevents contaminating your house with fumes.
Prepare the area
Spread the drop cloth on the ground. Place the folding stool on top of the drop cloth. Put on your dust mask and safety glasses. Cover the seat and steps of the stool with plastic, securing the edges with tape.
Sand the stool
Sand all metal portions of the stool. Sand rust spots vigorously.
Coat with primer
Coat the stool with spray primer. Spray in short, even bursts, holding the can 18 inches away from the stool. Allow to dry.
Turn the stool
Turn the stool as necessary to prime different areas. Allow the primer to dry before you turn the stool again. Repeat until all metal portions of the stool are coated with primer.
Paint the stool
Shake the can of paint well. Apply the paint like you applied the primer. Allow to dry and turn the stool as necessary, painting different portions. Apply several coats. Let each coat dry for at least 24 hours between applications.
Remove the plastic
Remove the plastic from the seat and steps, and use your stool as you normally do.