It makes no difference. Any welding process will work mig, stick, tig Its all in the filler wire. For example 60 series stick rod 6010 6011. 6o thousand pounds per square inch . 70 series rod 7018, 7011 70 thousands pounds per square inch tensile strength. 7018 would be your best stick rod to use on mild steel(mild carbon steel). If rusty or dirty 6010 would be a better choice( less strength ). Using a series higher then your 70 series wouldnt be recomended. 80 series is getting into a higher chromium 2% preheating may be required . and if you go to a 90 series 5% chrome preheating is required. your third number on stick rod is postion 1 good for all postions 2 flat and horizontal, 3 flat only. Your 4th number is aflux number. the first number is alway e for electrode. On other pocesses like tig your bare wire will have a number on it. example er70s2 this would be for mild steel 70 series. with any process when welding with mild steel 60 or 70 series filler material is your best choice. All iam saying you need to match your filler wire with the base metal. The frame on a truck is just plain old mild steel . They weld on the frames at the factory. Welding on a frame wont distroy it . With proper technic any process will make a nice looking satisfactory weld.
