Tungsten Question

When should you use the different sizes, and does it matter?
1/16
3/32
1/8

Amperage, and arc control...That's really somewhat subjective as to what you prefer. Too much heat on too small of tungsten will melt tungsten...Too low of amps with too big of tungsten will eventually allow the arc to wander.

I'm having trouble with 1/16 melting a little over time, and 3/32 with the arc wondering. I am running my power arc 140 at 50 amps. The 1/16 tungsten is from Ram Welding supply. Not sure what brand the 3/32 I picked up a couple of pieces from a local machine shop.

Sean,
What mixture are you using? I am using 1.5% Lanth and have not problems at that amperage. Are you using AC or DC? If AC, what is your AC balance. If you are using too much positive time in the balance you most likely will roast your tungsten.

I like the parameters given in the CK Worldwide specs chart:
http://www.ckworldwide.com/tech-3.pdf

You can change the grind of your tungsten to make a difference in allowing more heat delivery capacity, or more directional control. It's helpful when you know you are going to run a little hot (or a little cold) for the size of tungsten you have on there.

For any given diameter tungsten:
* A "Sharper" tip grind, and/or with less of a flat ground on the end (or even, no flat ground on the end at all, in an extreme case -- leaving the tip "needle sharp") will provide more directional control of the arc/heat.

* A "Blunter" tip grind, and/or a wider flat ground on the tip will provide more current carrying capacity before the tip melts.

And certainly the "alloy" of tungsten used can have a huge influence over the current carrying capacity as well. Pure tungsten is lowest, zirconiated one step up, and any of lanthanated/ceriated/thoriated a further step up in terms of current carrying capacity.

I'm running 2%(red). I try to use a little more sharper point. I have not played around with a duller point.

Yes sizes matter, Check out this website, download the manual and look on page 4 for info on max amps etc for sizes and shape of points http://www.ckworldwide.com/technical.htm

I heard that size will also matter depending on the size of your gaps but I was able to fill ~3/8 gap with 1/16 rod by leaving it in the puddle and moving side to side. I have run into the problem where I needed thinner rod for the thickness of the metal I was trying to weld. By the time I could melt the rod, it wanted to burn a hole in the metal.