I was at first disappointed in the way this machine wouldn't weld strong to the metal on my pickup. I made sure the metal was good and clean and shiny, but the welds wouldn't hold very good at all. But after about to give up on it, I found that the metal on the body of my automobile has a galvanized coating on it, so even though I had the paint all off of it, the galvanization was what was preventing a good weld. After sanding through the galvanization the machine worked really good. It is way faster than a stud welder. The only thing is the instruction manual is vague and useless, so you'll need to watch a video on youtube to figure out how to use it.
Tommy 
