Q. I am getting back into racing and am starting to build a new chassis(asphalt hobby stock class). I have a two part question. FIRST: What type MIG welder would you recommend for chassis construction ie; mild steel,roll cage etc.? Can I get by with the smaller cheaper models? SECOND: I've heard that MIG welds may be weaker due to cold starts and low visibility of the weld puddle. Is there an easy way of inspecting MIG welds for strength? (Submitted by: Andy Munthe from Elk Mound, WI)
A. First, I would recommend the Millermatic 210 for your chassis work or at least a Millermatic 175. These are the most popular in chassis building. You can't hardly walk 10 feet in any direction at Hendrick, Roush, Childress or DEI without seeing one of these units. If it's good enough for them.... Your second question relating to cold starts is usually an operator setting problem or using too small of a machine or too large of a filler wire for the amperage range you are welding in. If you look at the linear welded area around the tubing, gusseting, and triangulation of bars, you shouldn't have any cracking problems unless you use the wrong filler, take a massive hit on that tube where it passes it's elongation percentage (stretch), or you are force-cooling the weld bead. Use a small weld gun to give you the best reach into a joint. Our M-10 or M-15 gun would be a good choice. I wouldn't be afraid of MIG welding your racer - 98% of Nascar teams are MIG welding chassis together. Thanks for the question. Hope this helps.