Way back when we tried the needle scaler doo-dads at the welding shop. We used them to knock off weld spatter. They weren't worth the hassle and the noise. We had better results with the spatter spray that you spray on the steel before welding.
In the long run we stepped up to bigger, better welders and different wire. After that the needles scalers weren't needed and never used again.


I never tried them on rust or undercoating but I can see how the could be effective.


Bobby

 

I worked underground and we were building an ore pass dump, the guy I was working with bugged our shift boss for months wanting a needle gun to clean his welds. He finally got , hooked it up to the hose, I asked him to give me hand to lift an H-beam so he slung the needle gun over the beam he was welding on and it snagged the quick connect and fired the needle gun down the ore pass which was open for 27 levels. He never got to use it and was never seen again....lol