Hello, My dad has a lincoln 185 precision tig, and I have been laying down some aluminum beads with it. Problem is that sometimes the aluminum will not get shiny so I can stick the rod in and start the bead. I have tried it with the auto AC balance going, and it seems that with the AC balance full on the cleaning side it will be easier to start. I amusing a freshly sharpened 2% thoria tungsten and a gas flow of 16-17 cfh. This is on .060 or so aluminum sheet. Any suggestions?
well 1 st off 2% toungton is for mild and stainless steel.you can use 2 %but you need to ball the tip insted ofof sharping it .you can do that by using dc reverse and getting a piece of copper or brass and just start a arc for like a second then your toungston is good for alumin .or you can just by pure toungston its green.also are you running the high fi.and you can run your gas up at 30 cause a slight breze will take your gas away .well im not fermiler with your machine but thats a start later kyle
Another thing is to be absolutely sure that the aluminum is clean. I mean wire brush the hell out of it. On BOTH sides(front and back) of the weld joint. Aluminum is tricky. Hard to see it melting sometimes. And in my experience the type of tungsten used or the shape of the tungsten tip wasn't nearly as important as keeping the shielding gas where it needs to be and cleaning the piece to be welded.
By the way, I'm not disagreeing with speedy about the correct tungsten to use or the shape it should be in, just saying that if you're getting a good arc, and can control it, the rest of the stuff is secondary.
When using the 2% over time a ball tip will form on it. I guess I will try the pure tungsten and see what that can do for me. It just seems that with the heat turned up even to 90 amps it wont melt the aluminum. Weird.
as mentioned here by others, cleanliness is next to godliness when doing aluminum use a new stainless wire brush to clean the aluminum, and don't use it for anything else. regular steel brushes will leave iron residue in the scratches making for problems. also any drafts will cause the shield gas to move away and let in air which will also cause problems, as will any aluminum transfer to the tungsten. so put up some sort of shielding for drafts and keep the tungsten clean and shiny on the ball tip. start with pure argon, and as you get more proficient you can use up to about 25% helium 75% argon mixes for heavier section work to produce more heat at the weld zone, any higher than 75% gets to be to hard to control the arc. also the helium mix gas is even more finicky to drafts. just more for you to work with bob g
What kind of aluminum is it? What filler rod? (Some alloys weld easier than others.) What gas are you using?
i always used 2% tungsten. a pointed tungsten will not get it done. you do have to ball the tip. sharpen your tip as usual, set to dcrev, bring your torch tip down to about 1/8" of either your steel welding table surface or a grounded piece of steeel at a 90* angle to the surface and bring your pedal in VERY gently. the arc will climb the tungsten. you gotta watch really close. there is a 'critical' point at which the ball will form instantly, so you gotta be quick. if you bring the power in too quickly it will race up and make a tennis ball on the end, and if the torch is too far off axis, the ball will form off to the side and will cause your arc to hunt. make sure your ball is only around 3/4 the diameter of your tungsten. try that. if you're working indoors, your gas should be fine at 17 if your torch angle is correct. and if you make contact with your work surface or filler rod, you hafta redo your tungsten. once it gets contaminated aor the material transfer is too bad you cannot produce a true enough arc to weld anything worth keeping.
this is just some sheet that my dad picked up for me to try. As for the rod, I duuno. I could get it and se what numbers are on the rod. I am using pure argon for the sheilding gas. I am alo welding inside the garage with the door open. But I am about 8 feet from the door around the corner, so, I dunno about drafts. But my main problem seems to be with getting the aluminum to melt. I will try using DC reverse on the steel and form a ball. maybe I will make a beautiful bead and can take a pic of it for you guys.
After you get the little ball made, switch back to Ac and bring tip really close to the alum, but don't touch it. Then "mash down" hard on the foot pedal to break thru the oxide coating on the alum until you see a shiny puddle form. Then quickly back off foot pedal pressure to the point where you can lay a nice bead. You can also use acetone or denatured alcohol to clean the metal after wire brushing it clean. This also helps break down oxide. Oh, I use stainless steel plate to form the ball. Works great.
For what it's worth I use a pointed Tungsten on aluminum under .090 or so.It seems the only way I can control the arc on the thin stuff.
it is best to use pure tungsten, 2% will work, but pure is the best, and like almost every one said, clean clean clean, and pre heat, when i weld heads, i alsways take a rose bud torch to and preheat them, it keeps the welder from working so hard red dog redrum chop shop
I bought some square tubing at OSH tonight and started to go to town. Welds look like crap, but there was penetration. I was running 90 amps, 15cfh, 4043 rod, 2% thoria rod balled up using DC reverse on steel, welding on 1" square 1/16" aluminum. I am embarrased at the weld quality, so I wont post pics of it. I also bought a large stainless wire brush to clean with. Thanks for the tips guys.
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