The skill of stacking beads uniformly halfway overlapping a previous bead is fundamental to multipass welding on pipe or structural shapes. This is some of the best concentrated stick welding practice there is.
Tanks, Reservoirs, Pontoons, can usually be repaired using a doubler patch that uses a lap joint
Usually this test is given with a procedure that allows for 1/8" electrodes.
But some welders are being required to use 5/32" 7018 which is more challenging. This video has a few tips that should help
Outside Corner joints on 11ga 6061 aluminum are enjoyable. This This Aluminum cube project is a good way to get some practice on outside corner joints.