I am in needing to do a few small bits of welding on me landy but its on the bottom of the chassis so since i cant really turn it over i need to do abit upside down.
make sure you clean back the areas your going to weld as best you can this way you will get less spit and spatter. set your mig up on some crap of the same thickness to get your wire speed just right .angle your torch so that you dont get stuff falling back on to the contact tip . good luck !
also try to keep the weld pool small, that way it tends to stick to the metal...
if it gets too big then gravity makes it fall and you tend to be laid underneath it!
If you're having problems controlling it then try welding in short bursts of a few seconds each...say, 3 - 4 seconds maximum and keep your hand moving as you count. It's a bit tricky to get used to it but it does come with practice.
After you've been burnt a time or two you'll get to know when the weld's too big and about to drop :-)
And turn the wire speed up a little for overhead. Burnback seems worse on overhead especially on the small migs - tiny motor is fighting against gravity!