After researching for a few weeks, making sure I understand the safety, I bought a small MIG welder/Flux Core Arc Welder:
http://www.princessauto.com/en/detail/mig-100e-flux-cored-wire-feed-welder/A-p8538886e
Here is my attempt at mounting a tube onto a sheet, both steel at 1/8" thickness:
My technique was basically to come down at a 45deg angle and slowly move across the sides, for about 60 - 90 seconds total. I kept the tip of the gun very close to the metals, kinda just dragged it along. I chose the wire feed speed as recommended for the metal thickness according to the manual.
It felt strong but then to test it I tried stepping on it sideways. After I applied enough force (less than my bodyweight though) the tube broke off =(
What techniques should I use to weld this connection better?
Any useful vids would be great as well. Thanks!