AC versus DC is a long held debate. Is it better for a current flow to be unidirectional or alternating from positive to negative? In the end, DC is best for MIG welding and AC is best for TIG welding. AC is also suitable for stick welding. You will have to take some precautions. In any case, electricity is like fire and money; a wonderful servant but a terrible master. Use it wisely and you can be proud of a job well done.