Tig welding Alluminium

admin

hi all, just to begin with I'd like to say I'm a complete noob when it comes to tig welding. I've done a fair bit of mig, all hobby nothing proffesional. I started a new project that will be all Alluminium, and I wanted to Tig weld it so I got some nice neat welds. so, got my hands on a AC tig welder a few weeks ago, got it all setup now, and had my first attempt on a few bits of scrap.with the new electrode, I was able to actually get a decent weld for a noob, but the funny thing was I wasn't actually trying to weld yet, I was trying to ball the tip. after searching the net there were plenty of conflicting instructions on how to ball the tip, the only way I got it to ball, was to switch it to DCEN and fire it on a bit of scrap. after I did that though, when I then changed it all back, and attempted to weld a new piece, the arc jumped all over the place and just left me with a saggy pitted surface. should I grind the tip to a point? most sites said to ball the tip, but some were the oposite and said that it's better to have a point. what's you're thoughts?any tips for a noob? Thanks guys.
Reply:I always use a pointed tip for ALU and anything else for that matterSearch the threads, there is some useful info on ALU.
Reply:What kind of tungsten are you using?Bob.Miller Dynasty 200 DXMillermatic 211Hypertherm PM 600In Tool acquisition Mode
Reply:If your using green band (pure) tungsten, it wont matter what you are doing because its going to ball.  If your using anything else, you are usually supposed to switch to DCEP to ball it, I dont know where your read DCEN.  I usually just grind to a blunt tip and start welding and let it ball as I go.  If your HF set on continuous?  If it is not, you might experience some of what you are talking about.  Were you getting the saggy/pitted surface when welding with AC?  If you were it might be a shielding gas problem.  Aluminum is much more fickle than other materials when it comes to shielding gas, you have to have the flow set just right and no drafts at all, or else a "skin" forms over the puddle and makes it impossible to do anything.What kind of machine are you running?Have we all gone mad?
Reply:First, do not use pure tungsten (green) for anything, it has the lowest melting point does not give the ease of arc starting and arc stability of the alloyed electrodes.If you have an inverter power supply, do not ball the tungsten, use it sharp, it may ball up a little.If you have a transformer power supply, you can ball the tungsten using electrode positive (DCEP) on a small scrap of copper, brass, or steel.  Sharpen the tungsten, then form a moderate size ball, not bigger than the tungsten diameter.
Reply:Originally Posted by bear_2759hi all, just to begin with I'd like to say I'm a complete noob when it comes to tig welding. I've done a fair bit of mig, all hobby nothing proffesional. I started a new project that will be all Alluminium, and I wanted to Tig weld it so I got some nice neat welds. so, got my hands on a AC tig welder a few weeks ago, got it all setup now, and had my first attempt on a few bits of scrap.with the new electrode, I was able to actually get a decent weld for a noob, but the funny thing was I wasn't actually trying to weld yet, I was trying to ball the tip. after searching the net there were plenty of conflicting instructions on how to ball the tip, the only way I got it to ball, was to switch it to DCEN and fire it on a bit of scrap. after I did that though, when I then changed it all back, and attempted to weld a new piece, the arc jumped all over the place and just left me with a saggy pitted surface. should I grind the tip to a point? most sites said to ball the tip, but some were the oposite and said that it's better to have a point. what's you're thoughts?any tips for a noob? Thanks guys.
Reply:hi guys, to answer some of your questions,tungsten is a rare earth (grey)I'm using pure Argon as the gas.not sure about the HF, I'll need to check when I get home. I was getting the saggy/pitted surface with AC. I can't remember exactly what model the machine is I'm using as it's brand new, I can say it's a Uni-Tig 200A. I'll check the model and settings when I get home.I was reading allot on how to tig alluminium and one of the main things that kept coming up was how important it is to clean, so I've been giving it a good scrub down with a stainless brush (just for alluminium) and wiping it down with acetone so I don't think that's my prob.