t-joint aluminum- need help!

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I am doing something wrong and I can’t figure out what.  I am trying to welding an aluminum t-joint for practice.  I have a Lincoln 225 precision tig machine and NO aluminum experience.  I have practiced running beads in aluminum and I am now fine at that.  The problem comes when I try joints.  I am obviously doing something wrong.   I can’t even get them tacked together without it being a disaster.  I’m use to angling my torch to heat the steel on the upper plate and melt it into the lower without using any filler to tack it, I can’t even get that to happen with aluminum.   I am using 1/8 aluminum plates, I've messed with my angles, amperage etc. but I can't seem to join plates neatly.I would appreciate any help or direction.
Reply:Welcome to the site, any chance you could post a pic so the good folk here can analyze it for you?If you don't want to stand behind our Troops, feel free to stand in front of them.
Reply:Aluminum won't fuse like steel.   Keep a short arc, use lots O amps, and use the filler to bridge the gap.Have the tungsten stuck out to reach the root, Get a puddle going on both plates and stick the filler in.Forehand torch angle, 15 to 25 cfh Pure argon.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:As David R said welding aluminum is different that welding steel. You definitely have a suitable machine.Once you strike an arc, you may have to hang out (wait) a little to let the aluminum absorbe enough heat to establish a puddle.Remember that the flat base piece will need more heat than the vertical (tee) piece to initiate a puddle as long as they are the same thickness.Also as David R mentioned keep a short arc. Get a puddle started on the base piece and move slightly to the vertical piece close to the root. When you see wetting of the vertical give it some filler. Move forward and do it again. Soon you will get a rhythm going and it will become easier the more you practice. To tack the material as in a Tee Joint, you should be able to set enough amps to get a puddle on the flat base metal and then move over slightly to the extreme corner of the vertical piece and melt enough of it to fuse a small tack. I wouldn't be too concerned about that right now however, get something to hold the joint as needed.Post some pictures if you can. Good luck.
Reply:Thanks so much!  I really appreicate the help.  I will give it a go tomorrow.
Reply:I would add too that once you see the metal start to get shiny, like it is starting to melt, get a dab of filler in there right away. It doesn't have to fuse immediately, it just provides a 'blob' that is sitting there that can transfer heat to both pieces, and can join up with the two base pieces as it all melts. Then you can work the arc around to the two pieces  to get that blob to fuse.It's hard to describe, but you'll get it. When in doubt jab in some more filler so you have plenty in the joint to work with. To me it seems like manipulation of a very 'plastic' type material.It can also require a deceptively large amount of power. I'm doing 3/4" square 1/16" wall tube, and I have my max set at something like 185 amps.Keep at it, it will click eventually.And of course, get that crap super clean first !!!- John
Reply:SS wire brush the heck out of it before you start to weld it as well.  Those oxides love to diminish aluminum's ability to join.
Reply:Cleaning with laquer thinner or acetone after brushing will also help. It's amazing how a little dust or strand of wire from a brush will contaminate the weld. Just make sure it has evaporated before you start to weld. With aluminum, the cleaner it is, the better it is.If I knew that I was going to live this long, I would have taken better care of myself