Aluminum Tig Tips/Hints???

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I am weldling .050 Aluminum. ( basically sheet metal )  And the T joints and Butt joints are kicking mine!  LOL.. .seriously, I am having a tough time getting it right, consistantly... that is..   50 Amps, HF Constant, Balance/Dig on 4, Post flow 5 seconds...  ( Miller Syncrowave 250 w/ Foot pedal  ) I put enough to heat to add filler and metal wants to distort, and not enough filler doesn't want to stick.  Tried to manually pulse it and I tend to push through to much.  Just kind of confused here, any help is greatly appreciated!
Reply:What size filler?  Filler shouldn't be any thicker than your base material.
Reply:As will always be said when talking about alumnium ,it has to be CLEAN, as step one. Stainless brush until shiny right before welding, otherwise the filler will just not want to flow into the base metal becuase a layer of oxide are literally seperating them. Clean the filler too. Otherwise, I would suggest turning the machine up. 80 amps. Hit it hard at the start, you need to get the material up to melting quickly, if you sit there and let it cook it'll turn into a wet noodle on you. Hit it hard at the start, get a puddle, then let off on the pedal as it won't take much once you get it started.
Reply:Ya, sounds like you need smaller filler and pay close attention to your heat.  There is a small range in which everything flows really well on thin sheet so it takes some practice.  This is not easy stuff to weld.  Also make sure your keeping the filler within the gas coverage and not pulling it outside and getting it contaminated.Also from what ive been taught on aluminum you start off slow and ramp up the heat as you go.  This probably isnt as important on thin sheet but something to keep in mind.  Once you blow a hole in aluminum its hard to fix.Have we all gone mad?
Reply:Sometimes, you can use larger filler than your metal thickness, leave the filler in the arc, and it gives more for the heat to absorb into.
Reply:3/32 Tungsten ( red ) 1/16 Filler..  ( and yes, I think we should be using 1/16 Tungsten ( Green )    Thanks guys...
Reply:It can be done just fine with 3/32 tungsten.
Reply:Well, I switched over to 1/16 tungsten... changed my amps to 70 and it seems to of helped.. .but I am no all star yet... Lol... maybe by the end of the day tomorrow, I will have it down...   Thanks again guys!
Reply:The size of the sheet of aluminum is a factor. The larger the sheet of metal the more heat is given off and the more heat will need to be put in.AWS certified welding inspectorAWS certified welder
Reply:Adding to Donald's point, a smaller piece will get hotter and hotter; until the puddle falls out. You won't see it coming because you're so focused on your bead.9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:I would say if you are really paying attention to the puddle, you should see it coming very easily.Have we all gone mad?
Reply:When you see the puddle    take off and add the filler.   Remember puddle looks a whole lot different than steel.   It will look like a mirror or atleast really shiny.Like mentioned above, start off with a bunch of heat then back down a bit.  It can be tough, but you will know when you got it.Old rule of thumb  1 amp for every .001 in aluminum                                                  .050 = 50ampsLast edited by lewray; 10-16-2008 at 08:45 PM. weld it like you own it
Reply:If you can, use heat sinks if practical. It can make the welding easier, as the heat will stay concentrated, and more even for you. Copper plates are best, I have some different 1" thick steel chunks of scrap that I often use, it helps a lot on thin stuff.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:x2.  ^^^9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Thanks again guys! I backed it down to 60, and learned/learning to travel faster.I hardly ever floor the pedal on TIG, so 60 amps is perfect right now.. and I just hit it hard to start off and once the puddle starts run with it... and back it down slowly..   And yes, the size matters.. LOL...
Reply:sn0border88,Starting slow and ramping up your heat (on aluminum) is really bad advice.  Kinda makes me wonder if you've ever welded aluminum.Aluminum is a tremendous heat sink.  You have to start hot to create a puddle, then ramp DOWN as heat builds up in the material.Smokeshow,You're getting the idea.  Start hot (pedal all the way down) and back off as heat builds in the material.  Run fast.  Use the filler to control the heat.  Really a fine line here between keeping the filler close and melting the filler before you get it to the puddle.I would be using 1/16' 5356 filler for this job.  You didn't mention what machine (transformer/inverter) you were using, but if you really want to get fancy, you may try a 1/16" zirconiated or .lanthanated tungsten for this job.  They both hold up to heat a lot better than a pure tungsten.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Well after talking to an old timer and watching him for a while, I learned a thing or two...Here are a few pics...  Not the best at it.. but I am slowly learning.. No burn through!!!It looks thicker in the pics than it is..  almost looks 1/16, but its really .050...Oh yeah, I suck at pictures...Last edited by smokeshow; 10-17-2008 at 04:06 PM.
Reply:Theres some pcitures on here of an aluminum fuel cell i made from 3/16 sheet, that will probably prove I know how to do aluminum.Hey it works for me and the guy who taught me.  If you want to bash it, prove to me that it does not work.Heres the cellhttp://www.explorerforum.com/forums/...&postcount=534I often do repair work on 18-20" aluminum wheels, talk about heat sinks.Have we all gone mad?
Reply:sn0border88,If that's the way you were taught to tig weld aluminum, you were taught wrong.On the other hand, if you're happy with the welds you're producing (I won't comment), that's all that's important.I don't have to "prove" it to you.  You can prove it to yourself.  Get yourself a couple pieces of 1/8" aluminum and set them up for a butt weld.  For this setup, I'd set my Sync 250 at 125A, balance on 7, using a 3/32 Lanthanated tungsten, gas lens, a #8 cup, and no pulse.Floor the foot pedal and you'll get an almost instantaneous puddle.  This also serves to "blast" the oxides on the surface of the aluminum.  As you progress with the bead, have someone monitor your amp display (assuming you have a Sync 250 DX).  By the time you've progressed 3 or 4 inches into the bead you'll be down to about 110-115 A.  That's if you're maintaining a constant bead width.  As you reach the far edge of the coupon you'll have to back off even further to prevent blowing out the end.  You should also be rotating the torch to a near vertical position at this point to keep from pushing the heat too far ahead.I've only been welding aluminum for a little over 40 years.  Was building our aluminum fuel tanks in our race boats back in the mid-60's.  Long before we had the equipment available today.  Back then we used an old Linde Heliarc (non-squarewave)machine and helium as our covering gas.  Most of the aluminum tig welding I've done in the last 20 years, deals with marine fabrication where most of our material is anodized.  With anodized material we use what is refered to as a bump technique where we use a simple on/off button rather than a foot pedal.  Amps are set very high (190-195) compared to non-anodized aluminum.  You hit it hard, blast the oxides, Take a couple dabs and let off the switch.  Repeat.  Basically a form of manual pulse.Try that starting hot and backing off.  Think you may like it.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:You just proved that a different way works, which I never disagreed with.  More than one way to skin a cat right?Have we all gone mad?
Reply:The piece I was welding on was just a piece of scrap I bent to make two different edge/corner joints, so I could practice.Also, I think some of the differences in welding is, the difference between self taught and school taught and your buddy taught ya....