After years of being a daily driver and another couple of years sitting around on and off, I’ve finally gotten serious about doing a complete refresh of my 1990 Nissan 300ZX. I’ve got her stripped down to the unibody (save for the gas tank a few last hard lines) and tilted up on what Catmandont has dubbed the “door-tisserie” (two 36″ x 83″ solid-core door that have been radiused and attached to the bumper mounts):
I’m getting ready to wet blast the entire thing and then do some welding and smoothing where needed. After that, she’s going to need some sort of coating. I got a rough quote from a somewhat local place that said ~$700 to powdercoat the unibody (they have an oven that can handle parts up to 24′ in length and have done race cars before). While the price doesn’t sound that bad (especially compared to the $1400 quote I got from another place for dipping and phosphating just the unibody)(which is why I’m going to blast it myself instead), I have a few concerns:
1) seam sealer. I’m sure there’s going to be some finite amount of this crap stuck somewhere that I won’t be able to get it out. What will happen when it gets baked during cure?
2) inside the frame rails. Obviously it’s going to be hard to get powder in there. I’m probably going to wet blast, flush, and treat/paint inside them the best I can. Will need to be done afterwards if whatever treatment/paint I used won’t stand up to cure temp. Any suggestions for what to use inside the rails? I’d prefer not to do anything oily or waxy that might heat up and run.
3) DIY? Should I try to coat it myself and cure it with an IR lamp or build a modular oven around the car? I’ve done some calculations on the modular oven and it would be doable with a few of those Reddy propane or kerosene heaters to get everything up to temperature. With the modular oven, I’d do the bottom first with the car upside down and then the top/sides with it right side up.
4) some other coating besides PC? Thoughts of smooth or fine texture truck bed liner have crossed my mind. Criteria are that it needs to not be too thick as to interfere with things closing or bolting up right, needs to adhere well to bare metal or some very agressive primer, be durable/flexible enough to withstand any chassis flex and kicked up small gravel that may be on the road, and obviously have some UV inhibitors/stability.