A 180-amp MIG welder can weld anywhere between 3/8” – 5/16”.
However, you may also be able to weld mild steel that is 1/2″ in a single pass. The key to doing this is that the root or the initial pass needs to be done very well, then one has to lay the next pass on the bottom then top. This all depends on the material you’re welding and what it will be used for. One doesn’t want to play around with structural welds. This is why it is important to be a welding engineer and to have a welding certification.
One can weld trailers but must keep in mind that since they will be on the road, they must be insured, and drawings may be required with the weld specifications on them. They must also be done by a certified welder.
