Hello Mike, overall I prefer gas to Mig welding every time if I have access to both sides of the panel to planish the weld. The sill section was joined using the Mig for plugs on this occasion because of the location to grind them afterwards. Grinding Mig welds is not one of my favourite tasks. Mig welding is a chaotic affair, flash splatter wallop, then grinding off what you’ve just done with more noise and sparks, there’s something quite serene with the gas option.Super quality work there.
I guess you've gas plug-welded the outer sill bottom to the middle sill? That's how I've done it in the past, albeit with MIG!
Cheers,
Mike.
Ross