I need to make something and I need to know what gauge our sheet metal is. I am most interested in the body sheet metal. Doors, quarter panels, etc. I tried miking it but the results did not jive with a gauge chart I have.
What gauge is our G-body sheet metal?
- Thread starter Bonnewagon
- Start date
It's thin, maybe 18 gauge. I know it's not as thick as it was on my '72 & just waking past seems to add dings.
It’s not even that thick. It is definitely an odd size, near as I can tell it usually specs out at around 21 gauge which isn’t actually a size.
I usually use 20 gauge, as it’s the easiest to work with, 22 is too thin, and 19 becomes too thick and difficult to get to cooperate.
Thinner than the replacement piece I bought for my 05 sierra bedside.
Gonna agree with that 19 ga suggestion. During a recent grafting session, I tried to use body sheet metal on a vintage bike fender and found that the contemporary metal was significantly thinner than the immediate post war host it was being attached to; something like .030 worth of difference. I do know that for any type of butt weld where it is body metal to body metal, you should plan to have and use a copper backer plate to absorb the heat or blow through will be inevitable. Just went through multiple rounds of that with my Monte project and chasing blow throughs is not my idea of fun with a Mig welder.
Nick
Nick
You want to talk about thin? Whenever I need to repair a door or quarter panel or something, I just roll out a new patch panel. 🙂
Seriously, though, GM designed and developed our cars at the height of the gas crunch. Massive effort to downsize, minimize weight, and increase efficiency to combat the "new" foreign stuff from Japan that got a million miles per gallon was the number 1 goal. Thus, the thinnest metal they could use that would hold its shape until delivery was used to save weight. Recall too, aluminum components pretty much dominated the random showings until around the 1985 model year. I never understood the logic in how the components were selected, though, if there was any logic to it. It seems during 1984, for the Cutlass anyway, they used more aluminum at "random". My dad's 84 Calais with a 307 had an aluminum hood but a steel rad support. wtf? Yet an H/O never got an aluminum hood version or core support that I'm aware of. Maybe 3500 units out of 60 million isn't worth worrying about. By 1985 and after, though, I have never seen a factory aluminum hood or core support on any G47, but there was an increased use (it seems) of aluminum bumper supports by then.
Seriously, though, GM designed and developed our cars at the height of the gas crunch. Massive effort to downsize, minimize weight, and increase efficiency to combat the "new" foreign stuff from Japan that got a million miles per gallon was the number 1 goal. Thus, the thinnest metal they could use that would hold its shape until delivery was used to save weight. Recall too, aluminum components pretty much dominated the random showings until around the 1985 model year. I never understood the logic in how the components were selected, though, if there was any logic to it. It seems during 1984, for the Cutlass anyway, they used more aluminum at "random". My dad's 84 Calais with a 307 had an aluminum hood but a steel rad support. wtf? Yet an H/O never got an aluminum hood version or core support that I'm aware of. Maybe 3500 units out of 60 million isn't worth worrying about. By 1985 and after, though, I have never seen a factory aluminum hood or core support on any G47, but there was an increased use (it seems) of aluminum bumper supports by then.
So it is not just me. I did a lot of patchwork using an old Firebird hood. That hood was almost twice as thick as the Bonnewagon sheet metal. It is hard to get a micrometer reading unless the metal is clean cut and accessible. Pinch welds and seams are doubled up and not reliable. Short of buying some sheet steel I usually try to use an old car door, hood, trunk lid for my metal. Even a junkyard hood is worth ten times what it would cost in sheet steel from a supplier. I guess the only way to get a perfect match would be to use another G-body body part.
Yep, on more than one occasion I’ve put my sheetmetal gauge on a cut through the middle of a G body panel (most recently the Malibu fenders I cut the flares out of) and it always comes back the same: That weird between 20 and 22 gauge. I would say if you have any old G body sheetmetal available, use that. Otherwise my recommendation is to use 20 gauge.
I was using some left over steel from my 78 nova on mine.
Yeah thought it was 18 or thinner .I used an old mustang 64&1/2 year ect rear valace" panel ,and the metal was thicker and better quality makes me wonder about the other panels on vintage ford's !
