How to properly form ball on tungsten for Alum GTAW

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I've got a little aluminum job lined up for tomorrow. Material is about 0.090", so between 14 and 12 gage on a ferrous gage. My Alum GTAW experience is minimal. I am pretty sure that I should be using the white tungsten, although I've read some that say use red on everything? If I am remembering correctly....do I use DC electrode positive on a piece of brass or copper to form the ball. It will be mostly open corner joints. How should I fit them up for the best results ? We have a spool gun too, but my experience with that is limited too. I think TIG is the way to go...correct me if I'm wrong. The project is 4 rectangular access ports with lids to tap into a conical bin. they will have a 1" flange all around the bottom to allow for fastening with screws or rivets. Any tips would be appreciated....I realize that most of this has probably been covered elsewhere and I apologize for any redundancy. I 'll post pics
Reply:Try using 1/16 red sharpend to a point..I never ball the tungestion before hand and when the ball gets around the size of the tungestion I stop and put in a new sharp one..Works everytime for me because you have way more control of where the arc is going..Hope this helps.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:If you use green (pure) the ac current will form a ball almost instantally.  That is what a lot on this site call Old School, but it has worked for 45 years, I know of without any trouble and it is the one the pros say to use.  JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:I don't know what machine you are using, but if you want a ball, with green it will form its self.  Using sharpened red, I have more control of the arc and the puddle.    Its all up to you.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:im like ZAP  red on everything 3/32  sharpen to  point let ball on its own ------it will--
Reply:I just grind it to a dual tapered point and strike an arc on a clean piece of alum until its balled.  Usually you can start right on your piece.  The dual taper seems to help control the size of the ball though I have no proof.But red tungstens work just fine for Alu.Have we all gone mad?
Reply:Like most, I use a sharp 2% thoriated.Were thoriated tungstens available 45 years ago, when  people started using a balled pure tungsten for aluminum?Miller EconotigCutmaster 38Yes ma'am, that IS a screwdriver in my pocket!
Reply:What Tungsten do you think we were using 45 years ago.  JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:I have no idea... That's a couple decades before my time.Miller EconotigCutmaster 38Yes ma'am, that IS a screwdriver in my pocket!
Reply:Thoriated????? can you believe.   JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:The 1960's was a great decade especially if you were old enough to live it...Rock On ! Some of the best music ever Stratocasted out there.45 years goes by fast brother, so don't knock it.
Reply:Yes the 50's and 60's were a great time.  John G.  (stop the confusion)SMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:Originally Posted by dicharryThe 1960's was a great decade especially if you were old enough to live it...Rock On ! Some of the best music ever Stratocasted out there.45 years goes by fast brother, so don't knock it.
Reply:Getting back to aluminum TIG....I had a few goes at it today, but with less than marginal results. I can manage to run some decent beads, but the ones that go south really go south. I think I am getting contamination. I thoroughly brushed the joints with a new SS brush, but I didn't have acetone. I will get some tomorrow. Sorry, the pics are coming. I noticed on several beads that a small black line ran down the center....at first it looked like a crack, but on closer examination, it is a series of dark flecks.I am using 3/32 red tungsten...I tried sharpened to a point, as zap suggested, but it seemed to keep deteriorating...I also formed a ball using the DC reverse polarity on a piece of copper with which I got better results. I am not sure of the amperage because it is an older machine with different ranges and it doesn't have an actual amp meter.Can someone briefly give me the cleaning procedure before welding? I'm curious what the best abrasive is to use with aluminum. I have been using a flex disc, but it quickly clogs and I'm wondering if it is contaminating the edges.I'll post pics tomorrow to give you a better idea of what I'm talking about. I was so thoroughly frustrated today that I was in no mood for pictures. One last question...is it easy to fill a gap with Aluminum. I've got about 1/8 to fill in a couple places...using 1/8 material.
Reply:Stainless steel toothbrush..Acetone..Clean rags...Keep the Aluminum wet with the acetone and brush "with the grain" of the al..It will get darker and darker as you brush..Wipe off with the clean rag and repeat..It will get shinier and shinier everytime you do it and thats a good thing..Clean is EVERYTHING when it comes to Auminum tig...Hard to explane but the results are real...And gaps are no problem when the puddle and such is good......zap!Last edited by zapster; 11-13-2007 at 10:02 PM.I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I use Nylon Mesh abrasive wheels (McMaster-Carr Page 2595) on aluminum to prep for welding, it does a great job getting any grit from grinding wheels out of the groove and lets you easily see any areas that are not clean.  It also does it much faster than brushing with acetone and does a comparable job.As for the disk clogging, few ways to get around that.  Use aluminum grinding wheels, they are a world of difference from regular grinding wheels.  You can also use a piece of steel to unclog the wheel.  Cutoff wheels leave grit in the aluminum which is next to impossible to see and also hard to get out even when cleaned as mentioned above.If your noticing the trail of dirt, look really close when your welding.  You will be able to see the little flecks get drawn into the pool and that could clue you in to where the contamination is coming from.Last edited by sn0border88; 11-13-2007 at 10:28 PM.Have we all gone mad?
Reply:Originally Posted by TinbasherCan someone briefly give me the cleaning procedure before welding? I'm curious what the best abrasive is to use with aluminum. I have been using a flex disc, but it quickly clogs and I'm wondering if it is contaminating the edges.
Reply:Originally Posted by TinbasherGetting back to aluminum TIG....I had a few goes at it today, but with less than marginal results. I can manage to run some decent beads, but the ones that go south really go south. I think I am getting contamination. I thoroughly brushed the joints with a new SS brush, but I didn't have acetone. I will get some tomorrow. Sorry, the pics are coming. I noticed on several beads that a small black line ran down the center....at first it looked like a crack, but on closer examination, it is a series of dark flecks.
Reply:Vinigar and a SS wire brush is all I have used.  The oxide is cleaned off by the DCRP side of the AC sine wave.  Oxide on Al. will form instantly and only DCRP, will remove it.  Ever think why DCRP is used for Mig welding of Al.  ( Cleaning off Oxide).   JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:i think you've taken me too literally or slightly missed the point. the oxide layer can/will thicken with time. Al oxide is porous and can soak up moisture, dirt and hydrocarbons, all of which are bad from a welding point of view- especially any potential source of hydrogen.mechanically removing the Al oxide removes all (or at least most of) the contaminates.as you say the oxide layer will begin to reform immediatly but a fresh oxide film will be both thinner and (more importantly) free of contaminates. with the TIG process this also means less EP balance is needed making the welding more efficient (more heat to the part, less for the tungsten to endure)
Reply:I guess I was speaking to those who do not have the advantage of programable AC Machines.   John G.SMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:It wasn't a bad day... I bought some acetone last night and it seemed to make a world of difference, although I was still getting some dirt...all in all it turned out OK. I used the acetone, the SS brush, scotchbrite, everything that was suggested. Thanks to all for the tips and special mention to hotrodder ...I do prefer the balled tungsten, and I noticed that the red I was using was very resistant to forming a ball...I managed to get the gaps filled up...only 4 inches on each fitting and I can see how a SS backer would help. I have noticed ( in my 2 days experience ) that the back tends to sag. As far as adjusting the arc characteristics...this is an old machine...I don't think it has any features like that, but I'll have a closer look.One thing in particular that I noticed was the difference in the characteristics of the puddle between AL and Mild steel, or even SS. It is not as fluid, it's totally different...learned a lot today.  Contaminated tackLast edited by Tinbasher; 11-14-2007 at 10:48 PM.
Reply:
Reply:Contamination again...I can see it being pulled into the puddle...looks like it's coming from right at the edges of the weld
Reply:2days Eh?  Sure looks great! You are one heck of a fabricator. Nice professional work.DavidReal world weldin.  When I grow up I want to be a tig weldor.Real nice, looks like you're getting the hang of it! Clean is mean! What are those? At first I thought a wheel well but now it looks like sometype of hatch? Working with aluminum is the best.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Originally Posted by TinbasherGetting back to aluminum TIG....I had a few goes at it today, but with less than marginal results. I can manage to run some decent beads, but the ones that go south really go south. I think I am getting contamination. I thoroughly brushed the joints with a new SS brush, but I didn't have acetone. I will get some tomorrow. Sorry, the pics are coming. I noticed on several beads that a small black line ran down the center....at first it looked like a crack, but on closer examination, it is a series of dark flecks.I am using 3/32 red tungsten...I tried sharpened to a point, as zap suggested, but it seemed to keep deteriorating...I also formed a ball using the DC reverse polarity on a piece of copper with which I got better results. I am not sure of the amperage because it is an older machine with different ranges and it doesn't have an actual amp meter.Can someone briefly give me the cleaning procedure before welding? I'm curious what the best abrasive is to use with aluminum. I have been using a flex disc, but it quickly clogs and I'm wondering if it is contaminating the edges.I'll post pics tomorrow to give you a better idea of what I'm talking about. I was so thoroughly frustrated today that I was in no mood for pictures. One last question...is it easy to fill a gap with Aluminum. I've got about 1/8 to fill in a couple places...using 1/8 material.
Reply:Originally Posted by TinbasherAttachment 13885Attachment 13886Attachment 13887Attachment 13888Contamination again...I can see it being pulled into the puddle...looks like it's coming from right at the edges of the weldAttachment 13889
Reply:I am not completely familiar with those terms   I got some lumps that came through in a few spots...not too bad though. I am pretty sure the penetration was good, with it being an open corner joint. Thanks again to all for the help...I'll post some pics of the finished product tomorrow. To answer your question Microzone, they are access doors that get mounted on some conical bins that hold coffee. Tried a 1/16th balled white tungsten today ...it worked well for me. Zirconium I believe.
Reply:It looks like you are not lowering the heat with the pedal. That is probably why you are dragging those bits of carbon with you. If you cool off each bead using the foot pedal and a slight raise of the cup. You will find that contamination is washed out of the puddle. And will stay in just one spot and not follow you along the entire weld. Your stuff is very clean. But when you do not cool down at each bead, you risk running a crack the entire weld. Your material is thin so you may not experience this. This cooling action also will help stop any wash out from behind the weld. But those welds look better then a lot of mine. I would buy them. Fan or duct access doors? Sincerely,William McCormick
Reply:Thanks for the tip, I'll definitely try it. You are correct I was maintaining pretty constant heat with the pedal finding that I needed a little less as the joint warmed up, I was achieving a cooling in between beads, by pulling the cup away, but I think it was insufficient. They are accesses to manually retrieve samples
Reply:Finished product...Customer specified this oddball plastic hinge. I used pop rivets where they were hidden Under the flange, but the last thing I wanted visible on the top was the ugly underside of a series of pop rivets. I decided to use 6 lb tinners rivets and drew them right into the plastic. Much more attractive, but incredibly time consuming. About 4 hours today fixing the lids to them. About 12-14 hours into the whole job. A guy that does Alum everyday could probably knock them out in half that time, but there is a learning curve on everything
Reply:You get an "A+" from me.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.