Tig welding aluminum

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Hello,I am trying to weld 6061 t6 pipe 2 3/8" diameter to 1/2 plate 6x6 and Im drilling a 2 3/8 hole in the plate and trying to get about 3/8 through the plate so I can weld both sides for strength .I am using a dynasty dx 200 welder. Im researching online and i see you need 300+ amps to weld 1/2 aluminum but im hoping since im welding both sides of the pipe which is about 5/16 wall I should be ok, is this right?Im trying to make a flag/banner pole if your wondering.I am welding to a 1/4 in plate for practice at max 150 amp so im guessing im around 130 making decent looking beads but I dont know if this is enough penetration.I do not see a heat mark on the other side all around.Any advice/ help would be appreciated.Used to do this with steel which im alot more confident of my welds but aluminum is so much better/ lighter to work with.Thanks,Abbas
Reply:Just one weld will be strong enough.........just butt weld it on top......That large a dia. will be more than strong enough for that app.I like Alumix gas (25 helium 75 argon) for that thick of material.....1/8 tungsten  around 150 +  amps the gas makes it wet out better and no need to pre heatLast edited by B_C; 08-21-2011 at 10:00 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:150 amps is too low. Maxed out with the right settings and prep, that machine should do the job for that application.My guess is that welding 1/4" alum at 150 amps, you are going to slow to get the bead running. You're overheating the material and weakening the alum because of the large HAZ..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Another trick that can get more heat to melt larger/thicker stuff than your TIG welding equipment may be able to provide by itself, is to use a big torch to pre-heat the work "nice and hot" before welding on it.  A 300+k BTU propane powered "weed burner" can be very handy for this purpose.
Reply:Bevel the pipe, and preheat with propane torch. I would set the amps to WFO, the frequency to 75, the balance to 75, and use 1/8" tungsten. Upslope set at zero, downslope at .5 second, and stomp the pedal to the floor to get a good puddle formed. After that, you can modulate the pedal a little for proper puddle size. Add lots of filler, quickly......And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:I would start a puddle on the .5" wait till it will except a dab. add a dab. move to the pipe add a dab you should now have bridged the two materials with filler. Then I would just lay on it. At 150 amps you will have to wait a while for it to heat up(maybe 15-20 seconds) Unless you preheat. When it heats up you will notice the single dab/bridge you created will start to sink in. once it sinks in really good its off to the races you will need to add a lot of filler. I will probably pump an inch maybe more of 3/32 at a time. I dont know if this is making any since, one day im gonna start a thread with pictures of the different stages of a bead (mostly just the beginning which I find to be the hardest part). Sorry for the blurry cell phone pic. Its 1.5" tube to 1/4" i welded yesterday. www.performancealuminumfabrication.com
Reply:Mostly what everyone else has said except The 150 amps being not enough..... That's why I recommended using alumix gas 25/75Helium argon...... With this set up you shouldn't Have a problem......  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Ok so basically if I have the 2 3/8 hole in the 6x6x1/2 plate and slip that through and then just fillet the top the pipe going half inch into the plate is a safety and its basically wedgeing it self in there.Im gonna make one take a pic and see what you guys think.Thanks for the help
Reply:At the risk of sounding forward, how long is your pole?  Gussets between the pipe and plate would probably be a good idea, regardless.How are you beveling things?  Something like this? (left side showing beads, right side showing beveling): Attached ImagesLast edited by dbotos; 08-22-2011 at 12:36 PM.
Reply:Yeah that might be a good idea also if it Is going to fail it will be at the plate so Some gussets would be a good thing...I have built flag poles before that didn'tHave any gussets and are still doing fine.I guess it depends on how tall and how big the Flag?  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:The plate is kinda small for a flag pole Base.....most of the ones I've seen are at least 12 x 12.  What you using to fasten itRedhead bolts?  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Well this was actually for a banner pole design two poles 1 top one bottom 4 ft pole 3 ft banner.The beveling I did not even think about thats a great idea and also for the bottom because I was thinking of just maybe spacing the pipe 1/8 or 3/16 higher so I can make a lap joint on the bottom but if I bevel the 1/2 plate like you said I think it will take the hassel of the 1/8 think and making sure its square to the plate.When I do mount these I use the hilti sleeve anchors. There great.I think when I make flag poles will def use gussets.Last edited by [email protected]; 08-22-2011 at 05:05 PM.Reason: forgot something
Reply:Oh, well thats nothing you need gussets for just one weld also..........I was thinking flag pole 15 feet or more, dealing with high winds and a large flag......  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:i'm surprised nobody mentioned DCEN at an option, especially B_C. could give good penetration with lower ampsDynasty 200DXPassport plus w/ spoolmate 100victor 315c oxy/(act and prop)Miller digital elitemilwaukee power tools
Reply:Not really necessary for that type of loads, 4 feet of tube that large of dia.  one AC weld should be more than strong enough........  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock