Thank you for this comment. I enjoy hearing about intricacies of engineering processes-- particularly those that sound "easy" on the surface.
This gives me a deeper appreciation for cars with plastic body panels. I also wonder if DeLorean Motor Company took any of this into account when they designed the DMC-12 with stainless steel body panels.
Plastic panels are a whole bucket of issues in themselves. As far as I know, the color matching plastic panels are painted using a different process. That means the the front and rear fascia (bumper) of your vehicle are painted in a different plant (usually) from the rest of the vehicle. The colors have to match to a very high degree.
And yes, that's a big reason why they went with stainless. Stainless steel does corrode, just much less visibly than regular steel. It also has different physical properties like work hardening etc. It's also VERY expensive. Salty napkin math says $10,000 more for the Cybertruck.
> Plastic panels are a whole bucket of issues in themselves. As far as I know, the color matching plastic panels are painted using a different process.
I was thinking about "molded-in color" panels like the old Pontiac Fiero. That makes sense, though, re: painted plastic panels. They'd be a whole different ballgame and there's, I'm sure, interaction between the paint chemistry and the plastic chemistry that's probably pretty hairy.
Color matching seems hard, I almost think it is worth making the distinction clear and not even trying if you have different materials. I've watched my girlfriend hunt down matching dye lots of yarns to finish gifts when she runs out too early.
I bought 2 pairs of the same shorts a couple years ago, one in blue and one in olive. Both were used almost interchangeably in terms of exposure to sun, dirt, washing, and salt water. But on the green ones a section of the waistband is clearly differently colored where on the blue the colors still match.
The DMC-12 had stainless steel body panels, but it had a plain ol' carbon steel frame (designed by Lotus and similar in design to the Esprit) with an epoxy coating, and they have NOT fared well over the years. You can buy a new-build stainless frame for it, it only costs as much as a new regular car.
Same with old Land Rovers, people belive they don't rust being all aluminium. Chassis are steel, and those rot. Plus some other bits and pieces. New galvanised chassis are available, getting the body mounted is the fun bit so.
This gives me a deeper appreciation for cars with plastic body panels. I also wonder if DeLorean Motor Company took any of this into account when they designed the DMC-12 with stainless steel body panels.