Choosing the best rod size for an application...
Posted: Sat Sep 03, 2011 3:31 pm
My welding teacher is a MASTER of his art. In his career he's been all over North and South America welding. Welding for Nuke plants, aerospace, countless pipelines, countless structural with all processes. He is always saying how using a bigger rod will make you a better, faster welder. He also says the bare minimum heat he uses with 1/8 7018 is 115 amps and arc force at 40%.
At work I was given this job: Vertical up Tee joint. 4 inch wide channel. 3/16 inch thick.
Now I KNEW I could have welded this EASILY, making it look very nice, even, flat profile. All I had to do was use 3/32, 85 amps, arc force on 50%. But I always look to improve my skills as a welder. So I figure, I've got some good stick welding experience now, I'm pretty good at making a quality weld, and now maybe it's time to become good AND fast.
So going by what my teacher says, I thought I'd try 1/8 rod. I knew from experience before even striking an arc, that it was going to be HOT and very hard to handle.
115 amps. Arc force 40%.
About an inch up the joint I could see the undercut starting to dig in pretty far, and about 3 inches up I blew through one of the channels (the one that was butted up against the other) I pretty much knew it was going to happen as I was welding it. Either that or it would have looked like crap because I would have had to compensate by weaving it wider and wider as it got near the top, possibly causing some big grapes to freeze on top of the bead of the weld also (we all know what that's like).
There were a couple joints like this I had to weld. So I repaired the hole, and did the rest of all the joints my way, with 3/32 rod, and they all came out beautiful.
I know a few things I could have done to make 1/8 a bit easier to handle on such a joint:
1-pause longer on the channel with more heatsink, less on the one I burned through
2-weave wider from the start
3-turn Arc force to zero (Arc force is designed to increase voltage when your arc length gets too tight to prevent the rod from sticking, more voltage=more heat)
4-turn amps down to like 100
Solution 1 would make it a LITTLE easier, but I really doubt it would give me the quality weld I can do with 3/32 with higher welding speed.
Solution 2 would produce a weld that is too wide, and probably just as slow as 3/32 since a wider weld will take more of the rod to fill up.
Solutions 3 and 4 go against what my Master welding teacher has told me.
Now my teacher never SPECIFICALLY said that I should be using a 1/8 rod on a 3/16 vertical up joint. So I'm not saying his bigger rod, better welder theory is bogus. Maybe it just doesn't apply in this application?
I mean there IS a line somewhere you have to draw for what heat is TOO MUCH.
Did I plain and simply cross that line? Or can you actually weld that joint with a 1/8 rod 115 amps, 40% arc force, FASTER than you can with a 3/32 while still keeping the weld bead and profile consistent. I plan on asking my teacher about this next time I see him.
At work I was given this job: Vertical up Tee joint. 4 inch wide channel. 3/16 inch thick.
Now I KNEW I could have welded this EASILY, making it look very nice, even, flat profile. All I had to do was use 3/32, 85 amps, arc force on 50%. But I always look to improve my skills as a welder. So I figure, I've got some good stick welding experience now, I'm pretty good at making a quality weld, and now maybe it's time to become good AND fast.
So going by what my teacher says, I thought I'd try 1/8 rod. I knew from experience before even striking an arc, that it was going to be HOT and very hard to handle.
115 amps. Arc force 40%.
About an inch up the joint I could see the undercut starting to dig in pretty far, and about 3 inches up I blew through one of the channels (the one that was butted up against the other) I pretty much knew it was going to happen as I was welding it. Either that or it would have looked like crap because I would have had to compensate by weaving it wider and wider as it got near the top, possibly causing some big grapes to freeze on top of the bead of the weld also (we all know what that's like).
There were a couple joints like this I had to weld. So I repaired the hole, and did the rest of all the joints my way, with 3/32 rod, and they all came out beautiful.
I know a few things I could have done to make 1/8 a bit easier to handle on such a joint:
1-pause longer on the channel with more heatsink, less on the one I burned through
2-weave wider from the start
3-turn Arc force to zero (Arc force is designed to increase voltage when your arc length gets too tight to prevent the rod from sticking, more voltage=more heat)
4-turn amps down to like 100
Solution 1 would make it a LITTLE easier, but I really doubt it would give me the quality weld I can do with 3/32 with higher welding speed.
Solution 2 would produce a weld that is too wide, and probably just as slow as 3/32 since a wider weld will take more of the rod to fill up.
Solutions 3 and 4 go against what my Master welding teacher has told me.
Now my teacher never SPECIFICALLY said that I should be using a 1/8 rod on a 3/16 vertical up joint. So I'm not saying his bigger rod, better welder theory is bogus. Maybe it just doesn't apply in this application?
I mean there IS a line somewhere you have to draw for what heat is TOO MUCH.
Did I plain and simply cross that line? Or can you actually weld that joint with a 1/8 rod 115 amps, 40% arc force, FASTER than you can with a 3/32 while still keeping the weld bead and profile consistent. I plan on asking my teacher about this next time I see him.
then work in your comfort zone until you feel ready to crank the machine up and move quicker. You may burn that joint out quicker but if you blow a hole and have to repair it, or get undercut and the weld fails, have you really completed the joint faster than taking your time with a smaller electrode and less amps laying in a sound weld???? I think not.