I remember once a machinist brought me a coupling and said, "Run me a hot bead on the inside" to joint the coupling to a shaft. He was going to machine it out smooth later. I ran him a Hot 1/8" 6010 root pass at about 175 amps which really gave some penetration. He came back after I gave him the coupling and asked me what I did. I did just like you said, ran a hot bead in it. He said the weld was so hard that it was breaking his cobalt cutting tools on the lathe.
I dont think the weld was that good due to the lack of ductility from running too hot. Since the piece was heavy, the weld cooled quickly and was like super tempered.
Any time you run a rod so hot that you are getting buckshot thrown off, it is too many amps and the weld quality will suffer. Best to reach a balance where you get good easy starts, good penetration and small sparks rather than big buckshot sparks flying everywhere. Since every welder dial is a little different, each person will have to determine where that sweet spot is on their machine. There are guidelines for each size rod, but your machine dial may not be calibrated to the numbers shown. The new machines with digital amp meters,I have found to be pretty accurate when checking with calibrated amp meters that clamp around the lead.
