Arc wonder at low amps TIG 1\16th

[jeffscarstrucks]

First I want to say how much I enjoy reading the posts and how amazed I am at the level expertise that goes into some of the replies.
Now for my quandry: I was welding a t-joint on notched aluminum tubing that is 3\8ths Dia by.035 wall. I'm using a 1\16th 2% thoriated sharpened lengthwise to about a 1\8th inch point. The machine is a ...RED Square Wave 175 (Lincoln...my other 3 machines are Blue so don't beat me up to bad). The problem is that at the very bottom of the amp range the arc slowly rotates around the tungsten. I tried regrinding very carefully to make sure that there were no radial marks for the arc to follow (ground lengthwise). If I go down on the pedal to what must be around 15-18 amps the arc will straighten out. I am thinking that going down to a smaller tungsten will solve the problem but I don't think this machine will support that since I'm at the low edge now. I should say that this is more of an exercise for me as It,s been a while since I've done anything this thin! Also I am a hobby welder (drag racing disease) and don't do this for a living. I was able to complete the joint on the first try with this set up but was not at all satisfied with the arc quality. Sorry this is so long and thanks for reading...JEFF

[H80N]

Jeff
first off doubt that anybody would beat you up.. Most of my equipment is blue and I love it... but do happen to own one of those little red 175 squarewave machines... (bought it about 4 years ago and never could bring myself to sell it) have machines in the shop that cover that range and more.. and my mobile is a Trailblazer 301G..
but the little one just seems to keep a place...
Back to the subject.... that machine is rated down to 8amps... what is the slope of your taper?? and the grit of your grinder?..... longer taper.. finer grit and a sharp point on the tungsten may help...Also on aluminum you must clean the oxide layer off of it immediately before welding (aluminum oxide is a very good insulator and could cause arc wander) try a scotchbrite pad on a die grinder it should do it...
my guess is HAWK will come on and come up with the right answer if this does not help (he had one of those little red devils too)
Hope this helps
Heiti

[jeffscarstrucks]

HI and thanks,
The taper is about 1\8th in length and sharp. The grinding wheel is "fine"...not a good description I know, and only used for tungsten. I used a stainless brush to clean the oxide. I was hoping I covered all the bases before I started welding witch is why I'm at a loss. Thanks for the time to help! JEFF

[H80N]

Jeff
would make the taper at least 3/8 if not 1/2.. gentle curve with no shoulder
8=)
Heiti

[HAWK]

Jeff,

I used my Lincoln 175 Sq wave for several years. All the aluminum I did with pure tungsten and balled the end on a piece of copper using DCRP prior to welding. It welded smoothly all the way on the lower end. I rarely pointed tungsten for aluminum on this machine. The Dynasty is a different animal and I most always use sharpened and blunted tungsten (ceriated) for aluminum. That won't work on your machine-at least not well.

[HAWK]

Jeff,

If you must sharpen, try a chemical sharpener. It will not leave grind marks. Therefore, the arc won't have a wondering path. Just a suggestion.

[jeffscarstrucks]

Hi, thanks for the ideas! I went to my local branch but they were out of 1\16 pure so I'll run to St.Louis in the morn(sat) and pick some up. CeeKay is a large industrial supply house but they treat the little guy-me- perfectly. I don't work there or own part of it or anything like that; It's just good to be able to find parts and info like you are somebody! Thanks again for your help and hopefully I can play Saturday PM. JEFF

[jeffscarstrucks]

Hi, PART2... I went to the supply house this morning and picked up some pure and while I was there I found Chem-Sharp. I've only read about it on this board but have never seen it work. I,LL NEVER GRIND AGAIN! The point it made let the arc stay in place at the absolute minimum that the machine would keep it established. Once again, thanks to all who read or responded. JEFF

[HAWK]

Jeff,

I am partial to the Chem Sharp especially on thoriated. I don't like to grind thoriated and release radioative dust into my lungs just to get the right tungsten point. If you get carried away you can really eat some tungsten fast. Glad to hear you are up and running. I miss my little red 175 once in a while. If you ever get the chance, check out the Miller Dynasty series. Killer machines that rock on aluminum and titanium.