When I worked in the rig yards up to 3mm was a metal workers job , anything over was a platers job, there was a demarcation line set in place about it.I thought that as well but googled it to be sure first 3 results
https://en.wikipedia.org/wiki/Sheet_metal 6mm
http://www.castlemetalseurope.com/blog/differences-of-metal-forms-sheet-plate/ 6mm
https://www.quora.com/What-is-the-difference-between-sheet-plate-and-foil 5mm
I'll be grinding it off anyway it's only a bench top so not holding up a building or anything majorId grind that out, looks like youve got insufficient gas there
Mm, much to be said for 0.8 wire on a smaller set. It normally dives a bit deeperI would suggest using 1mm wire as this carries current better than 0.8 wire.
That 3 or 4mm will bug you my friend, checked my bench the other day and it was probably half mm, still try to get over that!
would be a problem if you want to build things flat and square
Breezey If you looking to fabricate any sort of framework etc grind it out and start over again, trust me on this one, if you're adamant on welding the plates together then look at trying to brace them out, maybe alternate stitch welds from front and back aswell.