Tig Welding Aluminum Norms

[H80N]

I am a self taught welder. I have tig welded for over 10 years, mainly steel stainless and silicon bronze. I would consider myself a very good welder. I have recently started working a lot with aluminum and am getting frustrated with what I feel are non satisfactory welds (mainly the presents of porosity).

The thing is that since I am self taught I don't know exactly what you should be able to achieve.

I weld mainly 1/4" 6061/6063 with 4043 filler rod. I have a brand new Dynasty 350.

An example of difficulty I am having is the following:

I am making a frame out of 2.5" 6063 square tubing with .25" wall. I miter the tube and bevel the ends to receive weld so I can grind flush. I use walter grinding discs made for aluminum. After I grind I sand off any burrs, clean with lacquer thinner and then wire brush with dedicated stainless brush. I clamp the frame down to my table and begin to weld. When I first puddle the joint and add a bit of filler rod, if I continue to hold the arc over the puddle it just bubbles. In fact any time I strike an arc and form a weld puddle on Aluminum it will just sit there and bubble. Is this normal? I don't see how it is possible to get a porosity free weld if my puddle is bubbling. I am running straight argon at about 20-25. I am welding at about 250 amps with 1/8" zirconiated tungsten with a gas lens. I have messed with all the setting to no avail.

The other 'is this normal' question I have is: with the afore mentioned settings, how long should my tungsten tip last? I grind them to a truncated point with the flat spot being at least 1/16" in diameter and I only get about 6" of weld before the tip start to deform (starts melting and splitting at tip).

Please help.

Thank you.

The guys have given some excellent advice... but this additional may help too...

Here is a short video that goes over settings for aluminum on the Dynasty... it is a different animal than a Transformer/Squarewave machine... This example has some similarities to your situation..
like I said, it is short and you may find it useful..

http://www.youtube.com/watch?v=ohuoW...feature=relmfu

and another one...

http://www.youtube.com/watch?feature...&v=OUr2hMIrDfo

[Portable Welder]

Yes, I use carbide burrs in a die grinder, Keep in mind its not that I never use a grinder. On heavy things like relining the bed of a gravel train when I'm using my push pull aluminum mig Yes I mainly use a grinder but on more delicate things that are going to be tig welded like a air conditioner line I try to stick with a wire wheel only.

[go2building]

Cool thanks , I'll try that
Kevin

[bobhdus]

Let us know how it went with the changes you made and what worked. When it gets to the melting point to add filler the puddle will get shiny. I sometimes find the welding rods need to be cleaned with acetone as well when I handle them with gloves that I also use for other jobs. If your new to welding Aluminum you may find yourself like a lot of people who have a problem getting enough or too much heat. If you get into the habit of "lead" footing the pedal you may find it easier to "bump" weld the aluminum. You "bump" by laying each bead one puddle at a time. That's how a lot of them folks get that stacking dimes look without overheating the base or weld.