One of the latest chronicles in my Mustang adventure has been to replace a badly dented/damaged B pillar or sail panel, whichever you prefer to call it. The damage was hidden by 1/2-3/4" filler. When it was removed it revealed a panel that could be used as landscaping for a model train set mountain range. After going around and around with a variety of fixes, I finally opted to replace the panel skin.
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We start by showing the damaged B pillar on this 67 coupe. You can see I was quite literal in my model rail road mountain range description.
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This is one of the few body panels that you cannot get reproduction. I called up CJ Pony parts and had them send me a replacement B pillar from a donor car in their salvage yard. I was just expecting the panel itself, but as you can see from what they sent me, they weren't messing around. That chunk of car was $175 shipped.
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I removed the paint with a wire wheel on an angle grinder. There were a few small spots of some deep set rust so I spot blasted these with a panel blaster using aluminum oxide media. The leader filler along the quarter panel seam is melted off onto some foil using a propane torch. After studying the panel carefully, I plan where to make the cuts and exactly what part of the panel I'm going to remove and transfer. I mask off where the cuts are going to be with tape. I will be going about an inch below the body line, and for two reasons: the metal is somewhat reinforced here since it's near the body line, and the body line provides and easy point of reference. I will be cutting the bottom just above the seam where the quarter panel butts in under the B pillar.
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I carefully remove the spots welds along the back glass channel. My preferred method for removing spots welds is making a small pilot indent with a small drill bit then cutting the spot weld with a spot weld cutter. Alternatively, I also grind the spot weld away with a pneumatic cut off wheel. The latter method provides a safer bet at leaving an intact mating surface. I cut the spot welds from the underside of the panel since I want the actual sail panel itself intact. Avoid using an air hammer in steps like these to remove the metal after the welds are cut; it tends to distort the metal too much. Instead, I use my small pry bar (about the size of a flat head screw driver) and carefully pry the metal apart. It leaves a nearly perfect intact surface.
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I make my cuts along my tape, and make a final cut along the inside corner of the rain gutter and the panel is completely removed.
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My cut will be wrapping around the back corner of the panel and running right along this seam near the top of the back glass channel. It provides a good point of reference for removal of both panels and installation of the new panel. The new panel over the old panel shows how both are exactly the same.
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The removal of the damaged panel is going to be nearly the same. I take a DA and sand on the body line to expose it. The old panel too was taped off and the new panel is placed over the old panel for a test fit. I chopped the back edge of the sail panel off so the new panel would fit over it better and more accurately. Then I made my traces as to where my cuts will be.
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The damaged panel is cut out.
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This is the back of the damaged panel showing the creases from the dents and just exactly how difficult/impossible this would have been to repair without panel replacement.
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I remove or neutralize rust and corrosion with a wire wheel/angle grinder followed by zinc phosphate treatment.
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Now I need to replace that section of damaged drip rail molding. I cut the damaged section from the car, and cut the replacement section from the chunk o' car from CJ.
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I shoot the B pillar guts with 2 coats of Eastwood Rust encapsulator.
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Since too much of the original drip rail was gone or cut away, I had to fabricate a patch so I could have something to mount the new drip rail molding too. I punch a series of holes in it with a pneumatic hole punch for plug welds.
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I attach the patch with plug welds and grind them down smooth.
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Second picture: I then weld in the new drip rail molding.
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The replacement panel too then got several coats of Eastwood Rust Encapsulator on the rusty backside. Now the panel is fit. At this point I check everything, then recheck. Then check again. I use panel clamps to help maintain spacing and hold the panel. I begin the welding process with a series of carefully placed and spaced tack welds to avoid warping the panel. It is critical to let these welds cool NATURALLY, otherwise the metal will shrink.
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After lots and lots of time (mostly waiting for welds to cool) the entire panel is welded in with a series of tack welds. All the welds are ground as smooth as possible. I use a flap disk on an angle grinder and do not grind too long in one spot as I want to avoid getting the metal to hot and causing warpage. I also let the panel cool naturally after I've been grinding on it for awhile.
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I finish the process by making my plug welds along the back glass channel. These welds too will be ground down smooth.
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After all the welds are completed, I fill over the welds with Evercoat fiberglass body filler. Fiberglass should always be used over a weld on a body panel as fiberglass filler is waterproof and will seal pinholes. Since I lost part of the body line because it was shrunken where the weld was, I recreated it by shaping the body line in the fiberglass. This actually went considerably easier and better than I had anticipated.
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I feather the filler and smooth the body line to make it match the rest of the line on the panel. I skim over the fiberglass with 3M lightweight filler to fill low spots and create a level surface. This is creamier and easier sanding than fiberglass so it's used to create a better finishing touch. Any small holes, sanding scratches, or other imperfections will be filled in with Evercoat Easy Sand glazing putty.