Metal surfaces all rust over time unless properly prepared and cared for. Truck frames are no different. Truck frames are exposed to dirt, mud, water, snow and other liquids from the road's surface. The frame holds the entire truck together and is how the engine is held in place. The frame should be taken care of and repaired so that it does not rust and become damaged. Rust can penetrate the frame and eventually make holes, which makes the frame unstable and unsafe. Learn how to paint a truck frame to keep your truck and frame in the best shape.
Separate the frame from the truck. This requires unbolting and removing the frame from the truck. Start under the truck and remove everything from the frame. The frame should be bare by the time you are finished.
Set the frame on two sawhorses or two props so that it is not sitting on the ground. Using a sandblaster, sandblast the entire surface of the frame. Make sure to sandblast the sides and underside of the frame. Clean the area and remove all of the sand after you are done.
Spray the frame with self-etching primer. This protects the metal from surface rust if you don't plan on painting it immediately, but it also allows the automotive primer to adhere to the metal.
Prime the entire truck frame with three thin coats of automotive primer. Spray the primer on the underside of the frame first and then the side. Follow with the top of the frame. Allow each coat to dry.
Paint the truck frame with three or four thin coats of paint. Use light, even strokes, starting with the underside of the frame. Make sure to get into all corners and cracks of the frame so that rust can't reach any part of the metal. Allow the paint to dry before handling the frame.
