Most knowledgable welders, and the manufacturers of these units, will tell you that these 110v models are great for sheet metal, and light duty bracketry, but are not heavy duty enough for fabricating a frame (such as your previous posts would indicate). At best they will do 3/16th (.187) material, usually meaning flat stock. Trying to weld box tubing correctly would be much more difficult. How you could do it would be to use the 110v unit to tack your frame together, then take it to a certified welder for finish welding where they have equipment for proper penetration.