TIG amperage, tungsten diameter, etc...

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I need to weld .063 & .083 wall 1.25" OD mild steel tubing.  I have the Miller Maxstar 150 STH and could use any help in setting it up.  I could use info on filler wire selection, tungsten diameter, amperage range, pulse frequency etc...
Reply:www.millerwelds.com   click on the link for weld settings calculator.  There is a weld settings calculator and it will promt you to input the tungsten size, the plate size and thickness. and give syou the proper amperage.  Good luck  Otherwise I would recommend 3/32" 2% thoriated Chris
Reply:I'd use ER70S-6 weld wire.  It will weld a bit smoother than ER70S-2 will.  Run with your machine at a higher pulse setting.  I think yours will allow 60pps as an option, and that will be fine.  It will also do fine on the 30, wo whatever it is around that range.  I'd not go down to anything under 10pps.  For a weld like this, you only want the pulse to help control the arc, not to put ripples in the weld.As for amperage...just crank it all the way up and use a foot pedal to adjust on the fly.Tungsten:  3/32" 2% thoriated is the cheapest, and most versatile you can get.
Reply:thats some great info guys...thxI see some filler wire doesn't have the "R" in the part number.  what does that designate?  also, the -6 and -2.  different metal composition?
Reply:The 6 and 2 designate the silicone content.  Not sure about the R.
Reply:ER70S-6 is the designation established by the American Welding Society, http://aws.org/ .E = electrode, as in GMAW (MIG).R = rod, as in GTAW (TIG).70 = 70,000 psi tensile strengthS or T = solid or tubular wire-2 or 6 = chemisty, don't have the details at hand, but Engliod is correct that silicon levels in the -6 are higher for more deoxidizing, also makes -6 more fluid.
Reply:Just found this link explaining filler metal designation and more.http://www.esabna.com/EUWeb/AWTC/Lesson6_1.htm