How to weld in a corner?

So no that I got my pp256 working I can finally lay down beads on aluminum in a straight line. I'm welding aluminum that's about 0.04" thick with a 1.6mm tungsten and a #5 lens. The aluminum is bent in a 90degree angle and I would like to lay small bead into the corner to strengthen it. I started with about .25" stick out but I couldn't get the arc concentrated into the corner. I increased the stick out to about 3/8" and it helped but it still wouldn't focus the heat into the corner. I end up with a huge filet weld. Any suggestions?

When I was in welding class, I would pull the tungsten out probaably close to 5/8" to get down in corners. I would also turn the heat up a tad if it needed it.

What kind of Tungsten are you using?

You could try to use a smaller cup and turn the heat a little.

Try 10% electrode positive and more frequency, use lanthanated or thoriated tungsten ground sharp with the grinder marks inline with the length of tungsten, smaller diameter tungsten helps a little too. On dirty aluminum the arc can jump around, mechanically clean aluminum welds the best for me.

One of those long skinny cups. Start in the corner with a lay wire technique so you really don't have to see very much.

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Originally Posted by srp

Try 10% electrode positive and more frequency, use lanthanated or thoriated tungsten ground sharp with the grinder marks inline with the length of tungsten, smaller diameter tungsten helps a little too. On dirty aluminum the arc can jump around, mechanically clean aluminum welds the best for me.

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So cleaning the snot out of the aluminum, 10% electrode positive, and the frequency knob just to the left of center seemed to help the most. Also stopping every four dips or so and letting the work cool keeps the bead small. I'm using the foot pedal with the amps knob set to about 40A and find myself right on the verge of turning off the torch but that's the topic of another post. Thanks everyone for the help!