A finished weld should look clean and pretty (maybe a relative term). I've seen some welds from professional welders, that were blotchy, and uneven. I wouldn't want them welding on anything of mine. I am an ASME coded high pressure pipe welder and a good weld should look like a stack of dimes.. Most welds are of sufficient strength even if they don?t have a beautiful appearance for what most home built subs require. However the real problem will be come evident down the road. As corrosion creeps in to the welds at spots that have porosity the growing rust in the weld will expand seven times. This creates enormous stress on the surrounding structure and will cause catastrophic failure. DJB