Tig aluminum lap and tee help?

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I'm starting tig aluminum lap and tee in class monday on flat position, any suggestions?
Reply:Use enough amps. I see way too many guys try to do alum by creeping up on the heat or setting the machine too low. That will work with steel, but not alum because alum is such a great heat sink. Hot and fast is the way to go. Use plenty of amps and hammer the pedal to get the puddle to form fast, then fly as you back off the heat as the piece heats up. More heat fast also allows you to bridge the two pieces easier and get started. In some cases it can help if you start the bead on your filler to get the puddle to bridge quicker, then start adding filler from there. Some guys have issues trying to start a puddle with no filler and loose it before they can stick the filler in. It takes a bit of practice to start the puddle and then add filler. Starting on the filler can some times help. Remember this is just to have a bit of extra material right as you hit the pedal. After than you melt the filler with the puddle, not the arc.Only other though is some guys like to crank the torch over way too far. You can do this with steel and get away with it, but alum you'll melt the filler before it ever reaches the puddle if you aren't careful. Keep the torch vertical and you put the heat into the plate and not out front near the filler.Without more info those are the best suggestions I can make..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:We generally use .125 in. plate with 1/8 filler wire. What amps should I set it on, 120 - 150? A lot of the guys in my class like using 103 for some reason and seem to make decent looking welds.
Reply:I set it at 200 amps, floor the pedal to start the puddle quick, reduce power as needed.Today I was at my kids high school using their syncrowave 250, I had him set at 200 amps AC all day for his projects.3/32 lanthanated and 3/32 thoriated, both performed the same with the balance at 7.3/32" filler rod - on 1/8" plate I do not care for 1/8" filler rods.Here is a good video on the welds you are about to do:http://welding-tv.com/?p=3877Edit: on my home machine, with no balance adjustment, the 3/32 tungsten does not hold up. We use 1/8" thoriated there instead.Last edited by MinnesotaDave; 02-15-2014 at 09:15 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:We use Lincoln Squarewave 275s. But anyways, when you use 200 amps, do you have to travel real fast?
Reply:And we use purple banded tungstens for everything.
Reply:Originally Posted by Robert RheaWe generally use .125 in. plate with 1/8 filler wire. What amps should I set it on, 120 - 150? A lot of the guys in my class like using 103 for some reason and seem to make decent looking welds.
Reply:Originally Posted by Robert RheaWe use Lincoln Squarewave 275s. But anyways, when you use 200 amps, do you have to travel real fast?
Reply:So, how do you gauge amps when using the pedal? usually I'll weld the whole length and taper down at the end at 120,
Reply:Originally Posted by Robert RheaSo, how do you gauge amps when using the pedal? usually I'll weld the whole length and taper down at the end at 120,
Reply:Read the puddle. It doesn't matter what amps I'm at while welding if I'm getting the results I'm looking for with the pedal. I know that's not a satisfactory answer, but it's the truth. I know what the puddle needs to look like while welding to end up with the toes washed in and the bead the correct height without over heating the base material. That's how I do this.You WILL screw this up. You WILL screw this up frequently. The point to practice is to gain the references you need to be able to do this correctly. With students I make a point of not only showing them what I "see" by doing demos, but make sure they understand WHY there are issues when they are done. Once you learn to spot your own mistakes, it's easy to know when you are screwing up. At that point you change how you weld so you don't have those issues. How long this takes depends on the student. I've had students who can't make a decent bead to save their life, while others fly right on thru. However the person having issues often learns more because they gain an understanding of when they are screwing up. They simply lack the eye hand coordination at the moment to execute the weld. The other guys may have simply found a pattern that lets them get by. At some point though the guy having issues gets all the pieces together and leaps ahead. The other guy usually hits a wall and gets frustrated because everything so far was "easy"..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:You sound a lot like my instructor. Sadly he's out on medical leave until sometime next month because he had a massive back surgery and I have a substitute who doesn't know welding so all the help I can get is from other students and the internet, lately the internet has helped the most.Last edited by Robert Rhea; 02-15-2014 at 10:04 PM.