My neighbor brought me a couple of receiver hitches that came off the fleet of snow machines that are used to groom the Iditarod trail before the sled dog race is run each spring. These machines take a pretty good beating, and the hitches have a couple of common failure points. He wanted me to see if I could add a few additional beads to beef them up. After burning off the powder coating and bead blasting, they were good and clean. Added a fillet around the three un-welded faces of the tubing, starting and ending on the ends of the lone factory weld. Then butt welded the inside end of the tube to the flange. He was very happy, and will be bringing in six brand new ones to receive the same mod, before they install them on the fleet. I chose ER312 filler, as I wasn't sure if it would be 100% clean, and it's supposed to leave a ductile, crack resistant weld. Plus, I just like the way it welds! Turns out the weed burner/bead blast got it plenty clean, so I'm sure plain old ER70S-2 or -6 should be fine for next ones.