A fresh coat of paint on your old mountain bike can help you give it a new look and keep it looking nice, even if you've had it for years. You also don't need to give it a detailed, intricate design to get it looking like new. All you need are some simple tools, a can of spray paint and you're ready to transform the look of your bike.
Remove all parts of the bike from the frame. This includes wheels, handlebars, water bottle holders, and chains. Also take off any and all stickers and decals on the frame. Look over the bare frame to double check and make sure you've removed every last bolt and screw.
Sand the entire frame of the bike until you've removed all remains of a glossy finish from the previous paint job. You don't need to remove all the paint from the frame, but you do want to make sure the surface of the frame is matt so the new paint will stick well. Sand down all outer surfaces of the frame, including the places where the metal tubes come together that are harder to reach.
Clean off the bike frame with a damp paper towel to remove any paint residue left behind by the sand paper. Use a dry paper towel to dry the frame completely.
Plug up holes in the bike frame with paper towels and duct tape. If the holes are small, you can simply ball up a small piece of paper towel and stuff it inside the hole. For larger holes like the ones the handle bars and pedals go into, you may want to first tape around the inside of the hole and then place a balled up paper towel on the inside. This ensures that the paint doesn't get inside of the holes and cause problems when it's time for you to reassemble the bike.
Position the bike frame to be painted. You can either lay it on one of its sides or hang it from a bar placed through the large hole in the front of the frame. If the frame is on the ground, spray one side of it and allow it to dry at least 30 minutes before flipping it over to spray the other side. If it's hanging, spray around the entire frame.
Apply two to three coats of spray paint, giving the frame time to dry in between each coat.
Spray on one or two coats of glossy finish after your last coat of paint has dried on the bike.
Remove the paper towel and duct tape from the frame, and reassemble your newly painted bicycle.
To remove decals and stickers, you may need to use a grease-busting cleaner to break down the glue holding them to the frame. Keep the nozzle of the paint can at least a foot away from the frame and move it back and forth relatively quickly to avoid paint drips and runs on the frame of your bike.
Do this in a well-ventilated area.