Help tigging aluminum outside corner.

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I'm new to tig welding. I've practiced laying a bead on some flat .080 aluminum and have been able to get satisfactory results. In trying to tig an outside corner weld on the same I have been having trouble getting a bead started. I can get a bead on one side going or the other but not both at the sams time time. Just can,t get the puddles on both sides at the same time and then getting them to to merge. Welder is a precision Tig 275. I've tried 3/32 thoriated and 1/16 th cerated Amps from 55 to 80, .Gas from 8 to 15 cfm. Apparently I have gotten come contamination in the weld jount that I have not been able to repair. How do I get the arc to not jump from one side to the other. and how do I clean up the severely contaminated joint and reweld it? I precleaned everything with a lliquid aluminum cleaner. It appears that the jount is contaminated. The fit is good and I clamped everything so the jount is tight. Any suggestions would be greatly appreciated.
Reply:I'd use the pure tungsten. I've always noticed the AC arc wants to go to one side or the other. I just get real close moving from one to the other (not being too hasty when starting the pool) and just dip the rod in. The filler rods might be bringing in the contamination. I was having some contamination problems with thicker aluminum and I found the thick rods to be the culprit. Hell, scotch bright everything if you're having contamination problems. This may be silly, but I have my machine maxed out 90% of the time and just vary the amperage as needed with the pedal. Give it a strong zap and the two sides might just join without filler. You might consider playing with the AC balance too.
Reply:add a little more filler on the start to get them to joindon't realy think its your tung type and when you get contamination stop, regrind the tung and clean the weld  before you start againidealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:You will need to remove all contamination from around the weld area to get the liquid aluminum to flow freely and in order to make a tack weld, allow surface tension to pull two separate puddles together into one weld bead.  If you have a shiney aluminum puddle on a test coupon of similar thickness, you should be good to go on your real workpiece.  If the puddle is not shiney and mirror like when liquified (but may have crud or skin on the surface with liquid puddle underneath, you need to figure out what is causing that contamination (which could be a variety of sources) and eliminate it.  Doing such trial and error work on a test coupon will prevent or at least reduce the number of failed weld attempts on your real workpiece.Sharpen your tungsten, and hold it very close to the work to pinpoint the heat close to the tungsten.  Use adequate current for the tungsten size to "saturate" the arc around the tungsten tip, and allow the arc to remain stable.  (If you use too little current for your tungsten size, the arc won't really know which way to jump off it, and it will jump off in varying directions, and the resulting heat inputted into the work will also be random.)For tack welding thin materials, one trick is set your tungsten stick-out so you can rest your cup on the work and also the tungsen resting right on the joint of the two materials, then right before you start your arc, rock the torch back a small amount, so the tungsten is held off the surface just a small amount, like 50%-100% of the tungsten diameter.  Adjust stick-out and cup diameter so you have a view of the puddle and filler rod access as needed, without the torch angle being so excessive that filler rod will melt before you can get over and into the puddle.Give it a good hit of amperage, a short pulse may be all that is necessary to get the puddles can flow together by themselves, without filler rod.  (There can be no air gap between the two piece for this to work.)  In other cases it will be necessary to accurately and timely dab filler into both puddles to get surface tension to pull them tight into one puddle.  Using filler to tack weld with TIG requires both hands - one to hold the torch, other for filler rod, so you need to have your work positioned perfectly without being held with a hand for this to work.  The filler rod will add material to the tack weld, making the tack weld bead stronger.Don't let the filler rod melt before you get it to the puddle.  Torch control, timing of the filler rod, and precision of the filler rod and torch movement will all need to be well controlled and may need practice to get it down for successfully TIG welding on thin materials.After you have the tack welds made, you can rest the heel of your torch hand against the work as you slide down across the joint for the full length weld.  If you are having problems with "runaway puddle melting", let your work cool before you start the arc, and use more current when welding to keep the heat closer to the tungsten.  It sounds counter-intuitive, but using less current for a longer time actually lets more heat soak into the work, which can make the puddle size harder to keep under control.
Reply:As stated in previous posts that you need to clean the area again is needed..As far as the "One Side To Another" arc goes..Let it arc on one side until it starts to melt a little then transfer the arc (Torch) to the other side and heat that up the same..Go back and fourth between the two combatants until everything looks the same and then with great precision  dab the filler between the two pieces and join them together..That is what I call the "Bridge" and once you get the bridge it will be a piece of cake from there..Steel don't do this..Aluminum does.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Zap,I couldn't have described it better myself.  TIG aluminum is its own beast.
Reply:Thanks for all the information. I have been practicing and trying some of these things and have seen some improvement. This has been a reel help.
Reply:try shorter arc length