Hi Mike!
SWP gave you some great tips to use and all I want to do here is to add on to the already great advice you're getting already!
The next time you strike your arc, position your head & line of sight so that you can clearly see the weld pool... this will definitely help you better gauge whether or not your tungsten is either too close or too far away from the joint in question. Position yourself ahead of the starting location so that you can clearly see the weld pool towards your line of sight but, make sure that you're close enough to clearly see the weld pool form... when you position your torch, does it have a slight "drag" or "push" angle towards the direction of travel? I ask this because, you want to have a slight "push" angle... In other words, the torch is ever so slightly angled towards the direction of travel - around 5 to 15 degrees from being perpendicular to the surface of the material being welded. When you introduce the filler metal to the weld pool, is the pool fluid? Does the filler "ball up" on you and do you feed it into the leading edge of the puddle? Do you feed the filler in a constant motion, continuously feeding the filler into the puddle or do you dab the filler in and out of the puddle? If you dab in and out, you must be aware that if you pull the filler out of the gas shield before the end of the filler solidifies, you'll contaminate the end of the filler and the next time you dab the filler into the puddle, you'll introduce contaminated filler inot the molten pool so make sure that the end of the filler is always shielded with the gas coverage envelope coming out from the torch also!
Also just to be sure, always CLEAN, CLEAN, CLEAN, the joint surfaces and the filler wire being used... this way you clearly eliminate the possibility of contamination from either of the two potential sources.
Make sure your torch parts are clean... I did'nt see you mention what was your gas flow rate from the regulator mounted on the tank, could you let us know what it's set at? Also, what is the distance of your tungsten stick out? I ask this because if it's sticking out too far and you did'nt compensate for it by increasing your gas flow rate then, you could be contaminating the tungsten if it's sticking out too far when combined with a longer arc length and while we're at it, what type of tungsten are you using for ferrous metals? What's the thickness of the material, what size tungsten are you using, what is the power source current set at? are you using DCSP or AC?
I know I gave you another set of questions to ponder through but, if you eliminate these potential issues then you'll be on your way to producing consistant high quality GTAW deposits.
I hope that some of this helps...
Respectfully,
SSBN727
Run silent... Run Deep!!!