Aluminum Tig weld strength?

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First off I have very little aluminum experience.  I was messing around and did a lap joint of 1/8" sheet.  They were maybe 6" long with a 3-4" bead I put on them.  It looked like a nice bead on it, nothing to write home about but it didn't look like a bird flew over it and dropped something either.I then took the 2 pieces and pulled them apart from the un-welded end.  The weld broke right down the middle of it.  Is this normal for aluminum welds?  Sorry I don't have where my machine was set at but material was 6061 with 4043 filler.  Material was pretty clean to start and I hit it with scotch before I started welding.
Reply:I too wonder what an alumi um brea should look like.  I have been welding them and smashing them to try to get the confidence to buy material for my project.
Reply:It is much easier to get a pretty weld with AL than a strong one. The aluminum should fail outside the bead of a proper structural weld. It should also penetrate through the whole piece. Even on 1/8 it will help to bevel the joint a bit.Lincoln precision TIG 275Millermatic 140 MIG
Reply:I like my fit up to be groove with 1 mm of land on 1/8,  this will full pen when given enough amps.If you had full pen with a nice melt on the other side you should try 5356 filler and do another bend test.Remember to clean the oxide layer on the back side also .Another thing.. weld speed should be about 2x the normal speed on steel so adjust amps ... hot & fast--------------------------------------------------------------www.becmotors.nlyup, I quit welding.. joined welder anonymous
Reply:Thanks for the replies.  There was not full pen on the bottom piece.  I will practice some more, but it is nice to know what to look for.
Reply:Some general characteristics of welds in aluminum:- Most steels are weldable, some aluminum alloys are jsut not weldable.- Some aluminum alloys are heat treatable, and some are not.- When welding steel, you can usually make welds that are as strong as the parent steel.  When welding aluminum, you can rarely make welds that are as strong as the parent aluminum.6061 is a heat treated aluminum alloy.  When you weld it, you pretty much 'destroy' the heat treatment in the HAZ.  Excess preheat, high inter-pass temperatures, and excess heat input during welding (wide weave passes) all would tend to increase the size/width of the HAZ, and thus make for a larger weakened zone (compared to the original parent material).6061-T4 will actually usually be stronger in the as-welded condition than 6061-T6 in the as-welded condition.And finally, although 4043 filler is an OK and accepted/recommended filler for welding 6061, just be aware that it is weaker (has a lower tensile strength) than 5356 filler or the original 6061 parent material.  The best laid schemes ... Gang oft agley ...
Reply:5356 and 5556 are more workable than the 4043 from my experience so far when it comes to thinner material and difficult work.  When you're running laps make sure to watch the bottom sheet closely because you can end up directing the majority of your heat into the edge of the upper piece.Welding Supervisor Department of Corrections.