Rust involves a process of oxidation on a metal surface, which destroys and propagates inside its molecular structure. Rust wreaks havoc on any metal surface, such as iron, steel or steel alloy. It occurs commonly on automobile body panels that remain exposed to the atmosphere a good percentage of the time. Pinhole-sized rust cavities mark the beginning of rust invasion, and they require immediate attention to stop their spread. Rust pinholes can widen and creep into the depth of the metal if they remain untreated. A do-it-yourself vehicle owner can patch rust pinholes, using some products, tools and a few basic steps.
Instructions
- 1
Place the vehicle in park or neutral and set the emergency brake, if working on a car. Remove and transport a rusted panel to a workbench, if repairing an appliance or component piece. Mix some mild dishwashing soap in a bucket and use a scrub brush to clean the rusted area. Dry it thoroughly with a towel, or use a hairdryer to remove all moisture.
2Probe the rust hole with a scratch awl, penetrating the hole to the other side. Note the resistance you feel while probing. Use the scratch awl tip to scrape away any rust flakes or metal peeling from the center of the hole outward. Delicately pick the metal surface, only in the rusted area until you have removed major flakes. Apply some masking around the perimeter of the hole, leaving about a three-inch margin all around.
3Fit some 60-grit sandpaper to a sanding block and sand the hole from the center outward in a feathering motion. Next sand perpendicular to the previous direction sanded. Sand the backside of the panel if you can reach it. Stay within the masking tape marks and sand down to bare metal on both sides. Switch to 220-grit sandpaper and perform the same sanding motions. Wash the surface with dishwashing soap and thoroughly dry it with a towel or hairdryer.
4Cut a small patch of fine wire-mesh screen with scissors. The patch should be large enough to cover the hole and extend outward for at least two inches over the bare metal in all directions. Circular patches work well for round pinholes. Mix a small amount of body filler into a plastic cup, according to the directions on the container.
5Apply a layer of body putty on the inside of the panel, covering the hole outward for a few inches on all sides. Press the screen patch over the layer of body putty, and then trowel another layer over it with the putty knife. Wait for the body putty to dry and cure according to directions. Use the putty knife to apply a layer of body putty to the outside surface, covering all the bare metal. Let the putty dry and cure according to directions.
6Fit 220-grit sanding paper in a sanding block and sand the outside surface of the panel until nearly level with the surface. Change to 400-grit sandpaper and sand the area until flush with the surface. Examine the area to ensure you have no high or low spots in the putty height. Wipe the area with a damp towel to remove the sanding dust, or wash with soap and water. Use a hairdryer to speed up the drying process.
7Paint the area with a good quality rust-resistant primer. Apply one coat; wait for it to dry at least an hour and then sand with 400-grit sandpaper. Apply a second coat of primer and wait for it to dry. Give it a very light sanding with 400-grit sandpaper. You will now be ready to paint the panel to its original color.
