Arc weld
Veteran Member
You made tanks with lap joint bottoms? I worked in a couple tank shops and never saw any lap joints except on cone tops where you used a come-a-long to form the cone top. You cut a bigger diameter circle than the tank with about a 1" hole in the middle to allow it to overlap when it comes together. Then you cut a straight line from the middle to the edge and welded 2 D rings on either side of the cut. You used a come-a-long to pull it together most of the way, then started tacking it on the tank. Then you pulled it together till the wide part of the cone was the same diameter as the tank. You were left with a lap joint and needed a small plug for the center hole. Sometimes you cut some excess of the over lap off. If you really wanted you could cut it so the 2 ends would butt together.
Did use a self propelled tractor to sub arc bottoms though. With 7024, the slag was usually self peeling except for the last little bit in the crater. Most guys would just use the stinger end of the next rod to pick the slag off before putting the rod in the stinger. With smaller diameter rods like 1/8" or 3/32" some guys would put 2 rods in the stinger when doing root passes on test plates so they didn't have a stop and start.
Did use a self propelled tractor to sub arc bottoms though. With 7024, the slag was usually self peeling except for the last little bit in the crater. Most guys would just use the stinger end of the next rod to pick the slag off before putting the rod in the stinger. With smaller diameter rods like 1/8" or 3/32" some guys would put 2 rods in the stinger when doing root passes on test plates so they didn't have a stop and start.