I have made at least one post, and read a lot of others, about where to get sheet metal for patches. Then somebody mentioned old door skins/hoods/decklids. As usual the old timers had a smart and simple solution. I've poked around old tin and newer stuff and the newer stuff just isn't the same. So for 40's/50's cars what is the appx. cutoff where things changed enough that this tin doesn't make good patches? What exactly is different about late model sheet metal?
Don't forget roof skins, door skins, etc. too. I think up into the mid-70s would be heavy enough to work, but the newer it gets the more the recycled content is.
new steel is just as good as old steel. i'd even say steel made in the last 40 years or so is BETTER than some of the old stuff due to better metalurgy. modern steel may be made largely from scrap, but they have a much better grasp on what is in it now. personally though, i wouldn't use used sheet steel unless it was an emergency or it was an exact or very similar donor, new steel is not that expensive, plus time is money, reuse a rusty and painted old piece of steel and you gotta remove all the old coatings, that takes time and materials.
"new steel is just as good as old steel. i'd even say steel made in the last 40 years or so is BETTER" you missed the question, hes asking why would using 1985 toyota corolla panels not work comparably.
Newer steels are not hard to work because of their recycled content. That is straight up BS. They are harder to work because of their higher carbon ( mainly ) and alloy content, which is put there deliberately to allow a thinner panel to perform the same or better job than its earlier counterpart. These modern panels are definitely a pain to work though. I have found that up to about the mid 70s ( as stated above ) will work. But I prefer to use new cold rolled steel, unless I'm scrounging a particular shape from a used piece.
I know I mentioned using scrap hoods and such when someone asked where they were getting sheetmetal for patch panels. I generally use stuff from the 70's back but I have a ready supply of cars that can donate hoods and doors and such since I part them out. The floorboards in my '73 Mercedes consist of a '57 Chevy trunklid skin on the drivers side front, a '73 Mustang Mach-1 trunklid skin on the passenger side front, and both of the rear toe boards are an NOS 70-something LTD door skin. The two trunklids were rotted away on the lower lips but the majority of the sheetmetal was good, just stuck my pattern on top, traced it out with a marker and cut it. The door skin was brand new but nobody wanted to buy it so I didn't feel bad cutting it up. I much prefer using old stuff like that not just because it's cheap, but also because it already has some paint on it and a lot of times that factory paint is really tough stuff, better than a spray can paint job for a floorboard patch.
Save the car parts and use tin from older 30s-70s appliances. refrigerators and washers they work well and some older fridges will have curves you are looking for.
Ha never thought of fridges. I used my fucked up '94 isuzu metal for some handle shaving and yeah, I bet that didnt help the job.
I've always used pre 72 North American. Think of a 72 Chev pickup as opposed to a 73-74. My brother in-law who's been a 30 year bodyman told me about this years ago. Up here in the rust belt the early Taiwanese patch panel would rust out before the original stuff it replaced.
In 76 the heaviest car GM made was Cadillac Fleetwood. By 79 the heaviest car GM made was Camaro Firebird. They've been Flimzy thin shit metal with chromed plastic ever since. I make most repairs with 18ga. cold roll black sheet metal. You can work the hell out of it.
I always use old body parts because I don't have any real metal shaping tools I like 40-50s stuff the best but mainly because of the nice compound curves of those years. If you need flat metal go buy new and save on the prep work as mentioned. I would probably agree on the 72 cutoff as I have got some good metal from a 72 Ford cab but the 73s are nitcably flimseyer and also tend to have more galvanization. I did also use up a whole hood from a 77 T-bird though, and it was very suitable, had just the crease that I needed. So I guess there is no hard and fast rule, try and stay with the same guage, especially if you are hammer welding.
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