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Fixing a Dent Like a Pro

Posted in How To: Body Chassis on April 12, 2019
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Photographers: Trenton McGee

Whether it’s on the street or on the trail, we have all heard that sickening thump of sheetmetal hitting an immovable object. Maybe that was just the tire or a wheel, you always think, only to get out and verify that you just put a healthy new dent in a formerly straight body panel. It sucks, but it’s part of being human, and humans make mistakes.

We know that sheetmetal damage is a fact of life on our trail rigs and don’t lose much sleep over it, but we try and keep our daily drivers looking presentable. It was while we were trying to back our trailer around some construction-related obstacles that we temporarily forgot about the stem wall at the end of the driveway, resulting in a fairly substantial eyesore right in the middle of the passenger door. It was way too small a dent to turn into the insurance company, and we tried to live with it for a while, but every time we looked at the truck, our eyes went straight to that dent on and otherwise very straight truck. Something had to be done. We knew we could find a place that would fix it cheap, but they’d probably just slather it with Bondo and do a lousy job of paint matching (silver is a difficult color to match). We wanted it done right but didn’t have a clue how to do it ourselves.

Enter Spencer’s Rods and Restorations. Unlike the high-volume collision shops that will cut every corner imaginable in the name of high turnover, this shop does very little collision work and instead works almost exclusively on street rods, restorations, and older vehicles. The shop has several SEMA builds to its credit, including a few early Broncos. The place started as a body shop school and evolved into a restoration center, so these guys know how to do things the right way. We followed along as technicians Chris Eisenhower and Brian Mazz made our mistake disappear and provided a bunch of tips along the way to assist others wanting to make amends for their sheetmetal transgressions.

Here is the dent we couldn’t not see every time we walked out to the truck. We’ve done far worse damage on the trail and never fixed it, but this dent was an eyesore on an otherwise pretty nice truck. We had the courtesy to restrict the damage to the door skin and not the fender, but we also managed to smack the door right across a prominent body line, which made the dent that much more visible and challenging to fix.
After the paint was sanded off the dented area, the next step was to physically pull the dent out. There are all kinds of obstructions to knock it out from the inside, so Chris Eisenhower at Spencer’s used a stud gun to weld studs to strategic low points in the dents, then used a special puller to gradually work the sheetmetal back into place.
It took a total of nine studs to get the dented sheetmetal roughly back into position. One of the stud got a little hot and put a small hole in the door, so Eisenhower carefully welded it up and then clipped off the remaining studs. The remains of all the studs were then sanded off to reveal roughly straight sheetmetal.
Once everything was pulled back into shape, Eisenhower used a straightedge to verify that the sheetmetal was within 1/16 inch of being straight and also to make sure there were no high points that would cause problems later. There’s no shame in using body filler, but you want that filler to be a thin film and never more than 1/8 inch thick.
We thought we were fairly far along in the process, but it turned out things were just getting started. After hitting the area with a D8 sander, Eisenhower did the first of what would be several very thin applications of body filler. There’s a bit of technique to mixing the right amount of hardener in the filler; you want it to set up fairly quickly, but you also want to have enough time to work it into the area you’re repairing. Ambient temperature has a lot to do with how much hardener and how much time you have before it sets up.
Eisenhower then used a fairly long sanding block equipped with 80-grit paper to bring the body filler even with the rest of the door skin. He first went back and forth horizontally, following the curve of the door, to knock down the high points. Then he transitioned to running the block at 45 degrees to ensure that the surface remained consistent along the area.
Much like reading a pattern on a gearset, sanding body filler will tell you how your fix is coming along. There are some spots here where the filler has been sanded away, indicating high points. Even reading the feathered area at the edge of the filler to the undamaged portion of the panel will tell you how even the filler is with the rest of the door. Eisenhower knocked down the high points with a body hammer, applied more body filler, and repeated the process several times in an effort to get the panel as straight as possible.
Using a guide coat is another way to identify low points in your repair. The dark guide coat will get sanded away on flat surfaces but will leave any low spots dark so you can see and rectify them.
The prominent body line in the middle of the area being repaired proved to be pretty problematic, requiring compound surfaces to be shaped so that they blended perfectly with the undamaged portion of the door. Eisenhower brought in Brian Mazz for a second opinion. Mazz offered several valuable pointers about reading the filler and addressing the problems. Simply running your hand across the repair can tell you a lot about how things are going. It’s tedious, but paying attention to detail now will yield a much better finished product.
After some more sanding with finer and finer grits, and the application of a skim coat to eliminate minor imperfections, the repair was finally ready for primer. As you can see, the area that needs to be painted has gotten much larger than the original dent, but this is the best way to ensure that the repair disappears once the paint is applied.
Once satisfied with the bodywork, the area was masked off and Mazz applied a coat of primer. The primer was only needed for the areas with body filler and/or bare steel. Although the primer sets up fairly quickly, the truck was left to sit overnight to make sure everything was fully cured.
After a little more sanding to ensure that the primer blended with the existing paint on the door, at long last the truck was rolled into the paint booth, where more cleaning and masking took place. You often hear that bodywork is 90 percent prep, and that’s 100 percent right. Skipping and steps or cutting any corners will show up in the finished product.
Spencer’s Rods and Restorations has a sophisticated digital paint matching system, but even with factory colors there can be upwards of eight variants for the same color. As a result, the human eye is best for making an exact match. Mazz chose the closest variant to our truck and then laid down three layers of basecoat, starting light on the door, then removing the masking on the fender and laying down heavier subsequent coats while carefully blending the new paint into the existing paint. After the basecoat had a chance to set up, three layers of clear were laid down.
After the paint was allowed to cure overnight, the final step was some wet sanding to removing any specs of dust or contaminants that might have made their way into the clear during the application process. The finished product is better than new, and it’s impossible to tell that the door had been repaired despite the rest of the truck being subjected to 13 years of Arizona sun. A dent repair is a lot of work to do right, but the payoff is you are left with no indication there was ever a dent in the first place.

Hazy Headlight Repair

While the truck was at Spencer’s, they kindly fixed our hazy, yellowing headlights. The Arizona sun is hard on vehicles in general and headlights in particular, and although our headlights weren’t in terrible shape, they had definitely started showing signs of age. Forget those snake-oil restoration kits you see at the parts store, as most of them don’t work. There’s an easier way.

Start by wet-sanding the headlights with 1,000-grit sandpaper. If they are really bad, start with a slightly more aggressive grit and work your way up to 1,000 grit. Sanding is going to make the headlights look worse, but actually what you’re doing is removing the hazy clearcoat that was applied at the factory and has broken down due to exposure. Clean them thoroughly, mask them (or remove them from the vehicle), and apply a couple coats of clearcoat. Professional-grade clearcoat is best and last the longest, but even the stuff in a spray can will work. The headlights will end up looking brand new and completely change the look of the vehicle.


Spencer’s Rods and Restorations

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