Downhand welds on Edges
(Moose Jaw, Canada)
Where I work, we run a lot of downhand welds... more so than vertical up welds. Never on anything thicker tank gauge, unless it has a wicked gap or requires more than 3 fill passes (3/8'' wall plates gapped about 3/8''). On gauge it works well because you can catch the edges and watch it burn in real nice, without warping the material. On the heavier stuff though, don't even bother... I've actually gotten a scraper behind a downhand pass and peeled it out of there. Like you said, the weld puddle gets out of hand and kind of 'floats' away from the penetration point.
Return to mig welding techniques.