As I am outdoor, I ca show you maybe my oldest but most important metal work I have ever done so far, it is my trailer :
I did it maybe 20 years ago now, and it's still as good as on the first day, I use it a lot for the garden, and also for transporting wood or even big pieces of furniture.
I made it upon a salvaged car rear axle (from a Peugoet 205, for the connoisor).
All frames are welded, and hot galvanized.
The floor is a sheet of outdoor plywood.
The front and rear sides can be opened, in order to extend the utility length.