I am not being a smart a$$. You weld the bottom like the top, just upside down.
If you weld the top with a side to side weave, do the same on the bottom. If you weld the top with a small U, do the same on the bottom. If you use a circle on the top, then do a circle on the bottom. When you get to the bottom, run a little past 6 o'clock and pause to let the puddle develop, and pull out. You will have a nice round button when you come down the off side, you go a little past the round button, pause and pull out.
You should not have to change the volatge and amperage for the entire cap.
BABRt's