K1500 cab corner replacement
I've got a '95 K1500 that had typical K1500 cab corners after 17 years. They rot from the inside out. There were actually no holes until I started picking at it and within minutes, I was left with this on both sides.
I know it's not really a good photo. But you can sort of see where I cut out the old corners in this photo. I wanted it so any seam would be concealed by the black plastic trim.
I know I skipped all of the important things like fitting the patch panels, and showing the method I used when I welded them in. But unfortunately, I have a problem where once I get started and moving along with a project I don't like to stop. On the driver's side, I used a backstrip method to weld them in. This method was actually somewhat difficult since these were aftermarket patch panels that don't fit as well as they should. More on that later. This picture is the passenger side, welded and filled. Yes I used fiberglass reinforced filler underneath.
This is it Friday night after I painted it. It's not perfect, but I'm satisfied. I used Glasurit 55-Line and Glasurit clear. The primers are Dupont.
For poor fit on panels the back strip method should have made it much easier.
Looks good from here.
For this repair I used aftermarket cab corners that are commonly available. GM doesn't make a patch panel for this repair. They sell the complete panel but that will set you back about $400/side. It would have been easier to install original replacement parts, but not really in the budget on a truck this age. The patch panels came with a legit e-coat from whatever sweatshop they were stamped in. They are made from 18ga steel which is as thick or thicker than the factory panels. I mentioned previously that I made my cut where I did so I could keep the welded seam hidden behind the trim. I also cut it there because that line just above the seam, where it dips in, is totally wrong on the patch panel. The angles on the patch panel are way too sharp. For me, the best way to deal with that problem was to not deal with it. This opened another can of worms. On the original cab corner, then sharpness of the turn as the panels wraps around to the back stays consistent from top to bottom. On the repro part, it is not. If you use the entire patch panel, this shouldn't be an issue. But if you do what I did, you'll find that the corner doesn't match up at all and the panel seems like it's not long enough from front to back. I rectified this on the driver's side with a lot of hammering, cutting, welding, etc. One other issue I had on the driver's side was that I didn't get the welded surfaces totally clean of any coatings (specifically, the inside of the factory panel on the truck) so this caused the usual problems but I pushed on and got it done.
On the passenger side I took a different approach. Remember I said the panel seemed to be a few millimeters too short from front to back, and the corners didn't match? I had the same problem on the passenger side panel as well. So what I did was pry up the ends of the factory panel at the front and back, along the strips where they're spot welded in. I left a little extra material on the patch panel. Instead of making a straightforward attack, I pushed the panel up into place from below. So the edge of the new panel slipped under the edge of the factory part. It fit very well. I spent 2 1/2 days playing with the driver's side. It took about 6 hours to get the passenger side fitted, welded, and ready for filler. I still had a problem with the corner itself not matching. What I did was cut a relief in the factory corner, which allowed me to hammer the corner down to the corner on the patch panel. Then I welded it back together and let the body filler correct the issue.
I used Bondo/dynatron filler because the place that sells evercoat wasn't open when I was ready to buy filler. Their fiberglass reinforced filler isn't bad to work with, but the regular lightweight stuff still sands like concrete.
I used DuPont primers because the supplier nearest to me sells DuPont. I also don't do paint and bodywork on a regular basis. I do it once every couple of years. I prefer to buy supplies in quantities I need, and DuPont sells primer by the quart and hardener by the half pint.
I hadn't planned to use Glasurit basecoat. I did have almost a gallon of Glasurit clear left over from a project a few years ago. I initially figured I'd buy some new hardener for the clear and use Diamont basecoat. I ordered Diamont, paid for Diamont, the guy went to the back to mix it, and returned a few minutes later saying he made an error and that he was going to mix it in Glasurit. No complaints from me. It was all a little trying at first, but in the end, it came out fine. I did have an issue last night when I started to tape off the roof to paint it. I put some tape down, and then went to move it a few minutes later, and pulled off a bit of my new paint. I'll post more on that in the general section.
I also painted the doors and the back side of the cab below the rear window. Eventually I'll paint the whole truck. I can't stress enough, just how much I hate the tedium of masking, so I wanted to get the "masking intensive" stuff out of the way. My last project was my Porsche 928 about 5 years ago. It has aluminum fenders, hood, and doors. So believe it or not, I actually did a complete repaint on that car without ever picking up a body hammer or dolly because paper thin aluminum doesn't take too kindly to being hammered. But it also doesn't dent much either. It's more prone to cracking. So on this I got to use my hammers, dolly, etc. I even took a crack at shrinking metal to get rid of an oil can in one of the doors which worked out well.