Quote Originally Posted by chevynut View Post
Yes I agree that if you take a patch piece from a car from the 50's it's going to be different composition than metal taken from a car built today. Today's cars are made with thinner, stronger steel. I wouldn't think of using metal from a modern car for a simple patch panel.

However, that doesn't mean you can't get metal of the same composition that they used in the 50's, which was probably a mild (low carbon) steel. Plain mild steel sheet you can get today is usually something like 1008 to 1020 steel (.08% to .20% carbon) and it's likely similar to what they used back then. I'm not sure but I doubt the thermal expansion of mild steels differs much.

CN? Do you have some information to back up this statement?? " Today's cars are made with thinner, stronger steel. "

I don't think there's any doubt of today's sheet metal (used in cars) being THINNER, but 'stronger'?? That differs from my understanding. I think today's car bodies likely use 'bends and contours' to make the panel strong enough, in spite of it being thinner (and likely less strong)...' If today's steel used in auto bodies is stronger, I'd really like to see some detailed information so I can modify my opinion...