I have heard that it is not a good idea to weld on car frames unless you know the right process in doing it, if I was to do it, I would be using a miller 225
arc welder; So I need to know the right way to do it. I have already cleaned all surfaces,cut to lenght my peices, I am going to put a frame into the
existing frame to strenghten the front bumper horns. I have 6010 and 7018 rod at home will this work or ?

Welding on frames are very difficult.  the steel on the frame is very hard, high carbon.  Maybe someone will know the number electrode this is.