"You don't understand," said Randy, shaking his head. "Rust is your friend!" Randy, a fellow Improved Touring racer, isn't screwed together all that tightly, so his pronouncements are usually dismissed with scant credence...but not in this case. In this case, he has a point. Scrutineers for the Sports Car Club of America, the sanctioning body overseeing construction of our little BMWs, would notice subtle attempts to lighten the car, such as missing hood, trunklid or doors.
Therefore, in our neverending quest to get our cars down to the class minimum, we must avail ourselves of all the tricks of our nefarious trade. Either that, or take the really devious route and, as Randy suggested, let nature's chem lab help us out. Mild steel, in the presence of water and oxygen, tends to render itself into oxide of iron. In turn, in its brown, nasty way, this stuff will scale off, leaving...an 'ole, a bit of nothingness which, allowed to propagate over time, will expand to include the entire car. In our case, Randy and I would prefer to let the bits that don't show evaporate.
BMW, in its all-knowing prescience, has thus constructed the sills and other hidden parts of its '70s-vintage unit-bodies to accommodate us perfectly. They even went to the trouble on my 3.0 CS to make a three-layer rocker panel, providing plenty of nature-ready potential holes. Just add water, and...presto! A BMW 3.0 CSR (Rusted). That's my challenge here, folks. Because much as I admire Randy (one of the great pragmatic thinkers of our time), I hate rust. Hate it! And when I finish with my One Lap Wonder, it won't have so much as a speck of rust on it. It will be well and truly "rust free."
This won't happen overnight. Mitchell Sam Rossi has regaled you with tales of terror referencing removal of noxious substances from the floor and underside of his ride. I'll add a little insight here, acquired at great cost: Let someone else do it. That's right. Farm it out, bubba. Because unless you have enough time on your hands to build that nifty scale model of the Great Wall of China out of sugar cubes, you're doomed if you try to accomplish this daunting task yourself. Oh you can do it, all right. But at the end of several weeks of gut-wrenching labor such as grinding and wire brushing and more grinding and scraping and sanding and God knows what awful stuff, you will be so sick of that damned car that you will want to push it into the nearest rock pit, laughing at the commotion as it sinks. I've done it. I know. And the rock pit is a shallower place for the experience.
So I sent my lovely, fragile coupe to the paint strippers. You might have such a facility in your town. It will be located in a section of town you wouldn't go into after dark. The premises will smell...funny. There will be razor wire on top of the chain-link fence surrounding the place (to keep criminals from stealing, what?). And the people running your local strip-atoreum will be...um, unusual. I think it's the fumes.
You will carefully trailer your pride and joy up to the loading dock. And they will immediately attempt to run the extended forks of the World's Rustiest Forklift in through the front window and out through the rear window of your delicate beauty, thus lifting a 3.0 CS by its most fragile part-the roof. After much screaming-laced-with-the-vilest-profanity on your part, they will allow you to scrounge up some very nasty nylon webbing, run it under the coupe's body, and thus preserve some sort of structural integrity as they swing it to and fro suspended from their wreck of a Hyster. This nerve-wracking process is necessary, folks, believe me, because compared to the alternative it's a weekend at the beach.
But what about those of us who want to feel that warm glow which can only be achieved by doing it our own selves, you say. Can you spell s-c-r-e-a-m-i-n-g m-a-s-o-c-h-i-s-t? Actually, I do have a few words of wisdom for you: Don't mess around. The fine details on this part of the process can consume you. Go after the undercoating and sound-deadening materials with the most powerful weapons in your arsenal. Terminate them with extreme prejudice. For that brittle, tar-like substance coating the floor pans, use a pneumatic chisel. Make sure the chisel is fairly wide, at least an inch. And set the air pressure on your compressor outlet at about 50 psi. Dig the chisel in between sound deadening and floor pan and...pull the trigger. Be careful. Too much air pressure will open up the bottom of your car like a cheap sardine can. But with proper care, this method will make quick work of the tar-from-hell. As for undercoating: Twisted wire brush mounted on mega-horsepower Milwaukee buffer/grinder. You can use insane pressure with this rig without worrying about flying wire brush particles arrowing into your cornea at inopportune moments. It makes a hell of a mess but, dearheart, remember, you asked for it. And it will remove that pesky undercoating.
Und zo! One way or another, I got rid of the crap squirted onto my car's nether parts by the manufacturer in an attempt to make it quieter or (ho, ho!) prevent it from rusting. Now what?
The fun! That's what! I will now render structure where structure ain't. I will undo Ma Nature's heinous efforts to convert my beauty to a pile of brown scale.
Observe if you will the accompanying photos. Note that some parts of the structure...aren't. Yes, stalwart readers, it's up to me to create what has evaporated. Not an impossible task. First: Leave the damn thing alone! Let me explain. Don't get all frisky with that 4-in. grinder and go cutting out every moth-eaten bit of structure. Your beautiful antique will sag like "Miss Nice Personality" at the debutante ball. You want to get this thing aligned before you go cutting and welding. Accordingly, jack and shim all four corners, one at a time, maybe even adding support in the middle of the rocker panel until, with the doors closed, the alignment gaps between door and body of your precious antique are so perfect they bring tears to your solvent-smitten eyes. Then, you've got it straight. Then, you can commence firing with that noisy, destructive grinder.
But wait! Can you remember exactly how all that unit-body sheetmetal went together? If so, quit reading, just go and do. You're one of them "Idjit Savants." For the rest of us, there are templates. Take some white posterboard, and using Marksalot, tape, whatever suits the third-grade artist in you, make a shape resembling that which has departed. Don't fudge. Do your best to get an exact fit, because where posterboard can be warped and casually bent into shape, 20-gauge sheetmetal isn't nearly as pliable a medium.
Once you have a beautiful piece of posterboard resembling the dear departed metal, you need merely convert it to a more substantial medium. I'll use 20-gauge sheetmetal, because in most cases this will be an upgrade, thickness-wise, on the original metal. The stuff is available in 4x8-ft sheets at your local steelyard (another scary place). Take your template, lay it out on the sheetmetal and trace around it. Sounds more and more like third grade, doesn't it?
Never fear, I'm about to get to the grownup stuff. Ah, yes. Big fun next time. Hang in there.