DC arc weld, amp setting for 1/8" steel?

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I'm  using a DC arc welder (Honda EW170).  I'm working on a rear bumper for my van:http://www.airextreme.com/4x4van/rearbumper/bumper.jpgI'm boxing the 3x6 rectangular tubing (.120 wall) with 2" round tubing (.120 wall).  Is it possible to do a *flat weld* (similar to a corner joint, where both pieces are flush), without undercutting the round-tubing portion?I cut the round-tubing to give me some protrusion..so I could do a T-type joint (in case the above didn't work).I hear from someone in this group, that 110-115A is good for 3/16" steel.  What setting is good for what I'm doing? (.120 wall mated to .120 wall).I'm also welding 1/4" receiver tube to the same 3x6 rectangular tubing (.120 wall).  Is multiple passes with 1/8" rod the way to do it?Later on, I will be welding 1/4" to 1/4"..is 1/8" rod OK (multiple passes), or should I go with a bigger rod?  What current setting is recommended for 1/4" to 1/4" plate?
Reply:byen00: I'd use 3/32 lo-hi on the tube stock, amps about 85. On the 1/4 plate, 1/8 lo-hi about 120.   revpol
Reply:I tried 1/8" 7018 & then tried 3/32" 7018 (16 yr old stuff in sealed containers).  The 3/32 welds seem to be better, the 1/8" rod is too big I think.  Does this sound right?  I know 1/8" rod is used for 1/4" & thicker metals.Is a weave motion used?  I kept the arc small & didn't use a weave..I was concentrating on seeing the puddle & following the T-joint.  Some of the welds didn't "grad" onto the vertical part & the welds looked "high" (short arc, not enough penetration).  I just cranked up the amps to like 125A.I'm thinking of going to a longer arc..can you still see the joint & the puddle?  At one point I was using a long arc, & the 125A setting just blew a hole thru the 1/8" base plate.It's really hard to change the orientation of the stick to *follow* the round path of the tube.  (as I got more experience, I could do the entire round path in one fell swoop).  Is it normal to stop (say 1/3" the circumference), change positions, & re-start?I really wonder how it's possible to do a roll-cage using a stick welder.http://www.hnmmotorsports.com/images/wDSCN0001.jpgI would think you would need to use a *short stick*.  How the heck can one control a 12" long stick to do these really accurate welds in a curved path??  Seems impossible.A mig welder would be easier.
Reply:1/8 is probably a bit too large.  Go back to the 3/32 and use 65 to 85 amps.  If you have an arc control setting, set it to the "softer" side of the arc.  The rod control is just something that comes with practice - old pipeline welders are just circus contortionists with helmets...Get it hot and hit it hard...
Reply:Stick with the  3/32rod, 70 to 85 amps,depending on how thick the metal is.it takes practice to weld pipe ,your machine does a great job with 7018 rods,so stick with them.3/32 rods do a great job on 1.4 inch steel ,just turn your heat up a little.you can weave a little or run stringers.either way if you put the weld in right it will be plenty strong.