How to Weld Patch Panels

Rusted area on car

Rust can creep up on your car and do plenty of damage before you notice it. It can appear under the he paint of your car, under floor mats, in corners of door jams--just about any place that can be reached by moisture. Watching for rust and taking care of it before it becomes a problem can help you get more miles out of your car.

Things You'll Need

• MIG welder Welding gas Welding wire Air compressor Sheet metal Die grinder with cutting blade 5-inch air grinder with a 40 grit disc Vise grips Welding helmet Safety glasses and heavy-duty gloves

Instructions

1. Find the culprit. You should check your car periodically for signs of rust. While many car owners are careful about tune-ups, changing their oil and filling their washer fluid, they are not so consistent about checking for rust. This is just as important to the maintenance of your car as rotating your tires and oil changes. Examine your car thoroughly. If you see bubbles under the paint, it is probably rust.

2. Determine how bad the rust is. Gently tap the area you suspect is rusted with the pick-end of hammer. If the metal is soft, you know it's rust. Continue tapping around the area until you locate the edges of the rusted area.

3. Outline the area. Using a permanent marker, draw a line two inches around the perimeter of the the rust. This line is your guide for cutting the rusted metal from your car. Be sure before you begin cutting that the line you just drew is in solid metal. It is very difficult to weld onto rust and defeats your purpose.

4. Prepare to cut. Plug your die grinder into the air compressor and begin cutting along the line. Do not cut one whole edge at a time. It is better to cut a little bit at a time, repeating the process until the piece of rust falls from your car.

5. Make the sheet metal patch. Once you have the piece of rusted metal out of your car, lay it on the sheet metal to make a patch. With the permanent marker, draw a line around the rusted piece of metal. With your die grinder, cut the patch out of the sheet metal. To smooth the sharp edges on the patch, use your 5-inch air grinder to lightly sand the edges until they are smooth and safe.

6. 

   Weld the patch. First you need to match the panel to the hole in your car. Keep the patch in place with the vise grips. Once the patch is secure, take your welder and bead weld one inch around the patch. This will keep the patch in place, allowing you to remove the vise grips. MIG welders grow hot quickly, which could result in the warping. To avoid this, finish your weld one edge at a time. Weld the top and then cool the welder with air from the compressor. Move to the bottom and do the same. Alternate welding and cooling until the entire patch has been secured.

7. 

   Flatten the patch. You will need the 5-inch air grinder one more time to smooth the bead welds down. This is important for the look of your car. Bumpy patches of weld look almost as bad as rust does. Prime the patch and order paint so the patch panel matches the rest of your vehicle.

Tips & Warnings

• When handling power tools and sharp metal, always wear appropriate safety gear such as safety glasses, gloves and long sleeves. When welding, always wear a helmet to protect vision.

Resources

• Welding supplies