Originally Posted by
Rambozo
There are two types of DC welding. DCEN (DC Electrode Negative (Straight polarity)) the names have changed over the years but it all means the same thing. DCEN is a lot more descriptive than straight polarity. This is the standard setting for most DC TIG welding.
DCEP (DC Electrode Positive (Reverse polarity)) This is the standard for stick welding, and very rarely used in TIG.
AC actually switches back and forth between these two, very quickly. In theory you could connect the leads either way on AC, but for all the controls to work right you want to connect the torch to negative and the work clamp to positive for AC TIG.
While learning, keep the pulse off. You want to do any pulsing with the pedal so you can see the effects based on foot position. With the pulser turned on, you won't learn the relationship between current and puddle control as quickly if at all. Learn the basics first, then add one feature at a time.
25 CFH is way too much for a #4 cup. try half that or less.
Again without knowing what you are welding it's hard to give settings. You should get in the habit of providing as much info as you can when asking for advice. There is a big difference between welding 24ga. steel and 1/4" steel.
A good place to start is with 1/8" plate. Not too thin, not too thick. Make sure it's clean. If hot rolled, grind off the mill scale, then wipe with acetone. If cold rolled, just do the acetone wipe.
Set your machine to one amp per .001" or 125 amps as a baseline and use the pedal for fine control. You will probably find that for a bead on plate, you will use between 60-90 amps, so about 3/4 pedal. You might start a little higher, but as the metal heats up, you will back off your pedal or bump up your travel speed to keep the same size puddle.
Preflow of .5 is fine, but I would bump up the post flow to 5 or 10. What you want is the post flow last as long as the tungsten is red, plus a little extra.
A 3/32" tungsten is good for that current range. You can use 1/16" if you keep things under 90 amps or so. 2% thoriated or lanthenated is a good choice.
Run in 2T and set up and down slope to minimum and start and end amps to minimum as well. You will control the slopes with the pedal. Use a light pedal to start the arc, then add pedal until you get a good puddle. Make your weld and adjust the pedal as needed to keep the same puddle size. If it gets too big, back off, too small, add a little more. At the end of the weld, add a little extra filler, then slowly back off the pedal until the arc goes out. This will keep from leaving a crater and possibly starting a crack. Once you understand all these things you can use some of the features of the welder to do some of that automatically for you.
In summery:
1/8" steel settings
DCEN
125 amps with pedal control
.5 preflow 10 postflow
Start, End, Up and Down to minimum.
Pulser Off
Arc force Off
3/32" 2% tungsten pointed
7-15 CFH argon #4 - #6 cup
Have fun
200DX control automatically goes down to ~20 Amps?
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