Wednesday, September 15, 2010

Sanding the mirrors and plastic bumpers

In retrospect, I probably should have prepped all of the parts before I started painting the car, but I was so excited to spray that I'm now going back to do some overlooked prep work. Today I sanded down all the "extra" parts of the car: Rear bumper corners, Rear-view mirrors, Sunroof, Rain gutters, Front spoiler, and Bumpers. I already stripped the bumpers when I was doing the rest of the car, and stripped the Sunroof, but never did anything on these other parts, mostly because they are all plastic and I was told not to use Aircraft Paint Stripper on Plastic, as it can soften and weakened the plastic considerably.
I resorted to good old sandpaper. I started sanding by hand on a small spot of one rear-bumper-corner. After 5 minutes of sanding with 150 grit, this is what I got. You can see the bumper is mostly faded Maaco-paint. Then you can see a layer of shiny factory gold paint, then a white substrate (primer or base-coat), then another layer of gold, then another white primer. Then the black which is the plastic itself:
I decided that sanding by hand was going to be too much, and went out and bought a few sanding disks for my 5" round hand sander. (I'm not sure if it is orbital or dual-action. (For plastic parts, I'm not too concerned about overheating and warping.) Assorted sanding disks (80, 220, 400): $10
Here is a picture of the bumper corner, pre-sanding with the faded paint showing. You can see the paint has already started to flake off on the bottom edge where I don't think the paint shop washed the bumper well enough. Sad paint.

Here is a picture of the bumper-corner after being sanded. because of minute variations in the flexible bumper, it didn't sand very uniformly. I feathered as best I could to give everything soft edges, and was OK with the mottled texture here which should sand out in primer. I mostly used the 80 grit which lifted off the paint rather quickly, and then ran back over with the 200 to soften out the scratches.
This is the rear-view mirror as it was on the car. The black spots are not from sanding. That is where rocks have hit the mirror and chipped off the paint leaving the aluminum underneath to oxidize to a near-black color. You can also see lots of white spots where the paint chipped off but the primer held. This was probably the worst looking spot on the car. I am really leaning heavily toward putting something on to protect it better. Definitely looking into a DIY clear-bra like this when all is said and done. For the mirrors, and traditional front and fenders too.

Here is the mirror after sanding. I did most of the sanding with my small 5" electric round sander, with 220 paper, and it cut through the paint pretty fast. I took it down to clean aluminum and kept the sander moving to prevent overheating and warping, which I can't imagine being too bad on such a small part.

Next up is the sun-roof. Earlier in the project, I had tried stripping the paint off of it thinking it was metal like everything else. The more layers I stripped off, the more I was surprised that I hadn't yet reached metal. I tried to gouge into it in a few spots, going down about half and inch seeing no metal. I have no idea what this thing is made of, but I got well past the crappy paint, and down into factory paint. Earlier, I spread some nice thick bondo onto the whole panel. (Too much, in retrospect), and spent several hours sanding it back off. I even had to use the 5" electrical orbital sander for a bit to get down through the top layer of bondo. Today, I block sanded the last bit of bondo to perfection, spending about an hour total. I have been most careful working on the sun-roof and hood, since these are the biggest and flattest panels; Ie, visible. The sunroof, especially, since it is right under your nose when you get in the car. It looks like crap, but it is as smooth as a baby's butt. Here is what it looks like now:

Next up are the rain gutters that run over the tops of the doors. I don't know what they are officially called (I couldn't find them on Pelican Parts anywhere). These are the biggest pain in the history of mankind. If there was any part of this project that really made me want to just give up, it is these things. I tried to strip the paint off them earlier, applying coat after coat of stripper. All the dips and odd angles kept the stripper from soaking in before dripping off. What's more, they are thin aluminum, so they are very light and are at the oddest angle. There isn't any way to put them on a saw horse, or table to get at the whole surface. I probably spent the better part of two hours just working on these things with the edge of my 5" round sander, then with the extension tip of a Mouse-Sander, then sanding the rest by hand. Aaarghh! I wanted to take these things and melt them down to molten aluminum, mold them into an anchor-shape, and throw them into the deepest part of the sea. I was seriously thinking about just tossing them, since they are semi-functional at best, and serve mostly to cover up the ugly weld between the door body panel and roof panel. Instead I patiently sanded them and worked on my zen meditation. Worst part on the car. Here is one before, and one after. Look, they are so long, I can't even fit them in the picture with any great detail. Dumb gutters!

Last up is the Front Spoiler. This thing is a bear of a part. It is one huge piece of molded urethane. I sanded over it once to take off the Maaco paint, which took about 1.5 hours, and got down to a good base for the new primer and paint to sit on. While sanding, I came across some pretty ugly rips in the plastic, and was torn on how to handle them. I half-felt like just painting over the rips, just as they were, being so close to the ground. Then perfectionism got the best of me, and I decided to fix them up the right way. More on that after I buy some epoxy.

Time spent today: 5 hours
Money spent: $10 on sandpaper discs

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