You can grind away to your hearts content Andrew, however this won't remove the slag inclusions, undercutting, porosity, and lack of penetration.
In short it's absolute rubbish, and I wouldn't recommend anyone turning out work like that, it has been carried out with too much stickout, running backhand with the wire feed set too fast, and the current set too low, and the operator running too fast.
This is the problem, anyone can call themselves a welder, without the actual ability to weld.
Brian
