Cool.
I sharpen mine to a point on the bench grinder, going with the grain.
I always put the tungsten in a cordless drill and allow the tungsten to spin flat out on speed 2 as I sharpen it.
You should be aiming for it to look like a sharpened pencil in scale.
Always give the alluminium a quick rub over with a wire brush before welding and its best to have a dedicated wire brush that you use just for that purpose. Then give it a wipe over with thinners. With TIG, and especially alluminium you want the metal to be spotlessly clean as any contaminates will cause problems.
Sometimes moving the earth lead to a different spot of what your welding can help give you a more stable arc.
Pre flow and post flow is very important with TIG. Give the peddle a quick press, with the torch away from the work piece to start with to ensure the tungsten has a good shielding of gas a few seconds before you actually start welding.
As you get to the end of the weld slowly back off the peddle (this will help prevent craters and pin holes) and then once the arc has been extinguished keep the torch in place for 5-10 seconds to allow post flow gas to continue to shield the weld pool as it cools.
As a general rule of thumb you want a second of post flow for every 10 amps your welding at.
Ensuring you have the correct gas pressure is also very important and will also help staberlise the arc.
What size tungsten and wire are you using?
1.6mm tungstens should be used with 1.6mm wire and 2.4mm with 2.4mm.
Using a 1.6mm tungsten will create a much smaller and narrower weld and will look a lot neater when say welding a tank/box etc. out of 2-3mm sheet. Using a 2.4mm tungsten wont look anywhere near as neat.
The angle of the torch/tungsten is also very important as is the angle of the filler wire, ideally the wire and tungsten should meet at 90 degrees and the tungsten should be angled at about 60 degrees to the work piece.
