Clean your vintage Schwinn thoroughly before you begin your project. Use warm water with mild dish-washing liquid in a bucket; clean with old rags or a soft sponge. Rinse the bicycle carefully.
Unscrew the bolts to remove the tires, the seat and other areas you do not want to paint. You can also use masking tape to protect the areas you do not want to paint.
Put on a face mask to protect yourself from any old paint dust. Older bikes may have lead paint, and it is better to be on the safe side.
Sand any rusty spots with metal sandpaper. Be gentle in this process and use circular movements with the sandpaper. Brush off any dust with a rag.
Hang your bike frame up onto old chairs or something else you don't mind getting paint on. Hanging the bike with make it easier for you to spray paint.
Spray rusty metal primer on the areas you want to paint. Be sure to wear your mask and give a good even coat. Wait for it to dry 24 hours.
Rub the primed areas with liquid sandpaper to give your bike a good surface for your paint.
Spray in even motions with vintage Schwinn paint or automotive grade acrylic enamel spray paint in your desired color. Unused vintage Schwinn paints are available with a few dealers, but Sherwin-Williams Automotive Spray Paint is considered to be the best, by some vintage Schwinn enthusiasts, to replicate the original Schwinn bike colors. Wait for it to dry and spray another thin coat.
Replace parts, remove the tape and put the bike back together. Apply vintage decals to give it a restored look.