Rust: an automotive cancer that plagues most all older vehicles.
If you’re like me and have an older car in New England, chances are you have some rust. It’s also likely that you have areas where the rust has become so invasive that entire areas need to be replaced and a chemical rust treatment just won’t hack it. What you need is new sheet metal. This is intended to serve as a simple primer for what to if you ever need to replace an area of the body on your vehicle (in this case, the rear rocker panel and wheel well of an EF Civic).
First, begin by removing any rusty metal. This rust was extensive so using a rotary cutting disk the rusty metal was completely cut away. If you’re starting a new project, check the condition of your cutting disk when you’re putting it on. If it’s getting small, use a new one. It’ll speed up the process and make your life easier. Be sure to put a few drops of lube in your air tools prior to use. Do yourself a favor and wear eye protection, a face shield, and hearing protection.
With the worst of it removed, you can begin to remove additional surface rust and prepare the surface for welding. To avoid getting blasting media inside the rocker panels, a piece of scrap sheet metal was placed behind the surface I was working. The media I chose to use was called “Black Beauty” and it is a course slag. Because it has sharp edges, the vehicle was covered in a tarp to prevent media from settling on the vehicle and scratching the paint. Normally I would recommend something a little easier on the metal, but got the stuff free so I am trying to get rid of it.
Now the surface metal is prepared for the patches to be fit and tweaked, then welded in place. Look at how clean that metal is, no rust! Having a rust free surface is extremely important to getting a good weld.
Here’s another shot of the area that was cleaned, showing the underside better. I removed the under coating with a putty knife and only media blasted where I needed to weld, because there’s no point in blasting where it’s not going to do anything. You can see one of my patch panels stuck in place directly above the jack stand.
The fit of the replacement panel is extremely important to the outcome of the final product. Any corners cut in shaping a body panel will be obvious with a glossy coat of paint.
To make the patches, I first made them using card stock. An old manila folder will do the trick. The patterns were transferred to the sheet metal and cut it out using snips appropriate for the gauge I was working with. To fold the metal, I made place angle iron in a vice clamp, and held the ends closed with vice grips. It works quite well. Always finesse the metal, if you beat on it, it will look beat on. Obviously. Body work hammers, clamps, anything can be useful in shaping your metal. I used my hands quite a bit. If you don’t have callused hands, wear gloves or you will get cut.
Galvanized sheet metal was used here, because I had run out of everything else. I don’t recommend galvanized sheet metal because when you weld it, because zinc, iron and lead fumes are released. Galvanized surfaces aren’t the greatest to paint etc either. More info on welding galvanized steel safely can be found
here
This is the first two panels welded in place. When welding sheet metal, you don’t want to heat the metal too much in one place. So tack your panel in place and then weld beads between your tacks. The white residue you see on the paint is zinc oxide, where the zinc galvanizing vaporized due to the extreme heat of welding. To weld, I used a standard MIG welder. Before welding anything, test weld some scraps together to get the correct speed and amperage setting for the material you are working with. If you neglect to do this, you with get crude welds or burn through the metal.
The inner panel was welded in last. In the middle top you can see where I burned through, oops.
Once all the panels were in place, all of the welds were ground down using a grinding wheel. This throws a lot of sparks, so as with the cutting wheel, wear a face shield and eye protection. You'll want ear plugs again too.
Once the surface was as smooth as glass, I did two things before applying a primer sealer coat. First, in the wheel well I applied silicone calking to the seams where all the welds were. I have no intension of making it pretty in there, but the silicone calking is water proof and spreads smooth with a finger. Afterwards, I moved to the exterior where I mixed a small batch of bondo and skim coated my metal. Why bondo when the patch fits so well? To get a super smooth finish of course. When the bondo is dry, it was sanded using increasingly fine grit sandpaper. Lastly, the site was masked and primer was applied.
I haven’t yet painted it, but when I do I will use truck bed liner on the underside to provide rock protection. If you have any questions, feel free to ask.
macbasq
Rich
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