How to Cut Out Old Rust Spots & Replace Them With New Sheet Metal

Rust on a vehicle's body happens when moisture meets bare metal. Rust is like cancer in a sense, it continues to spread until it's completely removed. Some rust can be sanded away if it's caught early enough. Once the rust begins eating through the rusted metal parts of the body, it must cut away and replaced with new metal.

Instructions

1

Put on fire resistant gloves and safety glasses. Cut out the rusted area of the vehicle body with the plasma cutter. If possible, cut only straight lines so that once the rust is removed, there is a square or rectangular area to be replaced. Pull the rusted panel off the car.

2

Measure the dimensions of the area needing to be replaced with new metal. Cut the new piece of metal to match the area it needs to fit, leaving 1/16 inch on each side to accommodate welding.

3

Put on a welding helmet. Tack weld the short metal rod to the middle of the new metal with the stitch welder to create a handle so that the metal can be held stationary during the welding process. Place the new metal into the spot that was cut out. Hold the metal as even and steady as possible and tack weld all four corners of the new metal to the vehicle with the stitch welder. Place a small weld every 2 inches all the way around the new metal. Allow the entire area to cool.

4

Grind all welded areas with a die grinder until they're flush with the rest of the vehicle body. Allow the area to cool and wipe clean.

5

Mix the body filler according to the directions on the back of the can. Apply body filler all the way around the new metal, filling all holes between the vehicle body and the new metal and covering the welds between the new metal and the vehicle body. Allow the body filler to dry at least 2 hours.

6

Sand down the body filler around the new metal. Start sanding with a low grit sand paper until the body filler is flush with the body of the vehicle. Finish sanding with a high grit, fine sand paper until the body filler is flush with the new metal and the vehicle body. The entire area should be smooth and flush all the way around.