mig welding tips-
grind all surfaces clean with angle grinder prior to welding. this makes a HUGE difference. this includes grinding off all paint, galvanizing (galvanizing fumes are extremely dangerous if inhaled), rust ect.
if you're using flux core wire it works, but i personally find it much easier to weld with co2. (this is true M.I.G.welding Metal-Inert-Gas) i'm sure a master welder could weld equally well with either style, but i found the solid wire with co2 to be much easier to learn on.
wear gloves and don't be afraid to get you head close enough to really see what your doing.
think of your hand movements like a robot. very slow and steady. sometimes ill hold the gun in one hand and rest the tip on top of my other hand, and just by bending your fingers you can get really consistent measured movements.
looks like a fun project!
what type of engine are you wanting to run off this gasifier?
looking good!