I am cutting up a skin from a water heater, it is 24/25 gage sheet steel painted measuring about 0.020" thick. There are 3 big pcs , 3x4, 2x3 and 2x2 , also 2 pces of louvered or vent pcs to let aire pass like for a radiator or combustion chamber air feed , as pictured.
Works nice to cut and hem or seem a lip and tuff enough but light enough for a tin snips.
As pictured.
John in Eagle River by Fred Meyers ak text 242-83two4, take what you need, I am slowly getting rid of it, I always like to have a chunk around for me or for you.
Also I have a bunch of galvanized 6" ductwork box plenems and flat stock. I reclaimed a house ductwork system so I have enough to do a (small) house. I can cut it to your size for an additional 5 bucks if that helps.
Also a tool box/work surface,I just fixed up, 60 bucks.
(Last picture red taskforce) Used but still usable.