While iron gates are strong, they are not impervious to rust. After a few years of withstanding the weather outdoors, the coppery-brown corrosion slowly begins to overtake your gate. Even when the gate has been covered with paint, it can chip; even tiny parts left unprotected will give rust the room it needs to develop and grow. With a little elbow grease and determination, you can get rid of the rust and make your iron gate look brand new.
Scrub the gate with a stiff wire brush to remove the rust. Move in a back-and-forth or up-and-down motion and work systematically from one side to the other, cleaning off the rust from each slat. If the wire brush bristles wear down as you work, switch to a new brush.
Attach an abrasive metal grinding disc to the grinder and use it very gently on each of the gate's slats to remove large areas of paint. Don’t press down hard or remain in one section for too long; this can grind away the metal. Don't worry about getting every bit of paint off with the grinder, only the large sections. Stay away from inner corners and crevices with the grinder.
Remove the bits of paint remaining on the slats and in the inner corners with a small abrasive pad. Clean off the gate with a rag, making sure you get all of the rust, paint and debris out of the corners and crevices.
Apply a rust neutralizer to prevent future rust. While the neutralizer is not necessary if you’ve removed every bit of rust, if there is a chance any rust remains, use the neutralizer. Hold the can of neutralizer eight to 10 inches away from the gate and spray evenly to coat each slat. Let the neutralizer dry according to the manufacturer's instructions -- usually 15 to 20 minutes -- and then recoat. Let the final coat dry thoroughly; generally you should allow 24 hours.
Spray an alkyd-base primer, holding the can eight to 10 inches away from the gate and coating evenly. Some neutralizers do not require a primer on top before painting. However, many dry to a black finish, making it difficult to cover the neutralizer with a light or metallic-colored paint. Let the primer dry according to the manufacturer's instructions.
Spray on the exterior metal paint color of your choice, holding the can eight to 10 inches away from the gate and spraying evenly. Let the paint dry according to the manufacturer's instructions and then apply a second coat if you like.