New to TIG, questions about AL welding

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I've had a few years experience behind a MIG and an arc welder as a hobby.  I recently bough a TIG as I wanted to be able to weld on aluminum.  I started out with some stainless steel, to get the hang of it, on my last project:You can see that I've got a lot of practice ahead of me to get an even weld, though I've gotten a little better at it now:So for the current project, I'm using a Hobart EZ-TIG 165i, 100% argon @ 17CFH, 3/32" 1.5% lanthanated rod @ 100A AC.  Parts were cleaned with a new wire wheel.When I was ready to try aluminum I had decided to start by welding an AN weld bung to a casting, the casting is 3/8" thick and the bung about 3/32".  I watched this first:   So I knew what I was up against.  Well, that part at the beginning where your brain is on drugs, how the arc scatters a bit and the pool looks porous is a lot like what I'm seeing except mine has like a layer of slag with the porosity that I can't even see the weld pool.  I just thought this was part of welding on a casting.The second weld I tried was on another weld bung, but to an aluminum fitting with an anodized finish.  I used the wire wheel to strip the finish in the weld area and surrounding areas.  Again, same problem.  I can't even see the weld pool because of the layer of slag on the top.  But I found if I time it just right I can use the filler rod to skim the pool just before it solidifies and get a smooth weld at least.I'm not sure why I get this layer of slag forming over the top of every weld I've tried.  My tank was getting close to empty so I took it in and had it purged this morning hoping it was just some contaminated argon, but it was the same tank I had used when I finished my last bit of steel welding and it was not a problem then.Otherwise I'm not sure what else to start looking at.  Any suggestions?
Reply:100A AC is nothing for 3/8" thick aluminum.  It is the single most overlooked thing when people are having issues welding with aluminum.  They think they can weld it with similar amperage like steel/SS.  For 3/8", you'd need your setting set to about 200-250A AC, floor it, and then back off on the foot-pedal right away.  Might be a problem for your machine to get to that amperage.    But yea, we see these aluminum problem threads about once a week here, and amperage is the problem 80% of the time. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:The ROT calculation for 3/8 aluminum is 375 amps plus another 50 to start.  You have little adjustment available for your machine.  If you just need the bung to seal and it carries no structural stress, I'd HAND stainless steel wire brush the material, clean with acetone, the preheat the 3/8" part really well with a propane torch.  Then max your machine out, stand on the pedal, and see if you can get a puddle to form.  I think your machine just doesn't have the balls for this, period.
Reply:Lots of cleaning, and lots of heat. And have a tap handy for that bung, in the same thread pitch etc as the bung. The heat from the weld will distort it slightly.
Reply:Two things come to mind. Your machine is a transformer tig. It is not going to have the focus, stability, or penetration that an inverter tig like the one in the video has. Your machine was designed to weld 1/8" max. The other is your machine is trying to melt the 3/8" casting without liquifying the 3/32" bung to oblivion. Maybe if the casting is 1/8" thick it might happen. As others have said, you need lots of power to melt to the root of the joint quickly without allowing the bung to overheat while you are trying to get the casting to melt. The casting may be dirty so you would have to stand on it to boil out the crap as well.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:I think I figured it out.  The inverter type welders need the tungsten ground to a point...  Amazing what a difference it makes, it actually forms the weld pool now.  Got the bung welded to the casting without a problem, moved on to some tubing, it's actually not terribly different from welding stainless as long as I can keep from accidentally dipping the tungsten into the pool.  Thanks for the input!
Reply:I wonder how large the casting really was to get a weld pool with such little amperage 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:The casting is a Buick 3800 oil pan.  It's at least 8mm thick.  The pool definitely wasn't able to penetrate very far, but at 165A it was far enough to weld on a fitting. I spent some time tonight welding some AL tubing together.  It was almost as bad as welding on the casting.  I got it off ebay.  It seemed like the weld wasn't self cleaning very well, some sort of sooty buildup would start to cover the pool and then the arc would start to dance around and was not able to maintain/restart the pool.  I had to file the top of the pool off in these areas and start over, so naturally the welds look like crap.  It was also a lot more sensitive to how sharp the tungsten was.  I wasn't sure if this was coming from the tubing that most likely came from china (2mm thick) or something in the tank?  I noticed it got worse as the tank was getting low.  Or is it just part of using an inverter type welder with no adjustments (has anybody tried to add any adjustments to a 165i?  something more for me to research...)Also it doesn't take long before I have to resharpen the tungsten.  Is the 2% lanth better than 1.5% for this?  Would a 1/16" tungsten work better?  I only have a 3/32" collet at the moment.  Torch is air cooled, is it worth the investment to change to water cooled?  I plan on using this a lot in the next few years, and want to be able to make my welds look decent.
Reply:For thicker Aluminum, try using a 80/20 helium argon mix.  Also, preheating the aluminum works to.  Use your Oxy/ Acetylene rig, but first only use the acetylene flame and allow it to turn the aluminum black, then add oxygen to the flame and heat the aluminum until all the black is removed from the surface of the aluminum. The Aluminum will now be at the right temp for welding.Also I have been using a brand of tungsten known as Wolfram, of the 2% Lanthanated variety. I really like it.GarLearn more here:http://www.weldingtipsandtricks.com/...ium-argon.htmlLast edited by Gar; 07-22-2014 at 10:36 PM.Lincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:Regarding the oil pan not sure what your doing to it? I'm assuming repairing a stripped out oil plug bung. If you were just doing it for something to try on cast or a solid reliable fix. Also a little off topic but the company TIME SERT makes very nice high end repair options for things like drain plugs or fords truck engine that like to blow the spark plug and threads out of the head. Back on topic with your machine casting like this are going to be tough specially if your new to aluminum. With cast specially dirty cast like a used oil pan which have a heavy impurity soak need to be clean,clean,clean. Usually I will run my O/A torch over it with strait acetelyne. Wire brushing and wiping with acetone until no impurities seem to bake out. Then on a machine that size I would go back to the heat and start by just running the tig torch over it to see how the cleaning action breaks everything up. If all looks well I would weld from there making sure to keep wherever I was welding preheated. All that soot you see is a combination of lots of impurities and your welder not having enough *** to wet a puddle.I have used a map gas torch before also on smaller parts and once a old gas grill but usually strait acetelyne is the best bet. Or you feel like pissing someone off and put it in the oven. Makes the food taste funny but one heck of a buzz. Kidding don't do that but I do know of guys that save old ovens to pre heat or bake out impurities out of casts with.Last edited by KD Welding; 07-22-2014 at 11:02 PM.
Reply:Oil pan is already done, adding a oil return for a custom turbo build:Looks like garbage but it doesn't leak.  Let's forget I ever did anything with it, and move on.I'm still working on some AL tubing though.  I've already 'welded' the tubing, just now trying to add a flange for a valve:This bothers me.  Compared to the 1st 12 seconds of the video in my first post, I don't see my TIG being able to produce a weld like that, ever. So I'm wanting to understand what I'm seeing while welding, how to fix it, and get better at this.  It's either something I don't have setup right, lack of adjustment on the 165i, or this tubing is garbage.
Reply:Please list all the settings are available in AC welding mode on your welder, and to what numbers you have set them to. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Shovelon says your machine is a tranny tig.Am I mistaken in believing that the Hobart 165i is the hobart brand of the Diversion 165?  I thought it was.If so, NO AC adjustment for Hz or cleaning.  No ability to stick weld.  Just amperage adjustment.  But still an inverter with a fixed AC frequency of 100-120 Hz.Did u actually get a puddle formed on those, or did you melt the filler with the arc and kinda just move the blob around?
Reply:Haven't used a 165. The 180 lacked some adjustments I see as important. I think an expert could adapt, but an amateur will struggle. Unfortunately entry level welders are at their best in the hands of experts.
Reply:Originally Posted by Willie BHaven't used a 165. The 180 lacked some adjustments I see as important. I think an expert could adapt, but an amateur will struggle. Unfortunately entry level welders are at their best in the hands of experts.
Reply:Originally Posted by MattstrikeThis bothers me.  Compared to the 1st 12 seconds of the video in my first post, I don't see my TIG being able to produce a weld like that, ever. So I'm wanting to understand what I'm seeing while welding, how to fix it, and get better at this.  It's either something I don't have setup right, lack of adjustment on the 165i, or this tubing is garbage.
Reply:Originally Posted by MinnesotaDaveYou didn't list a key factor - experience/skill level.Welding tubing to tubing is very difficult - if the thicknesses are different, then even harder.if you aren't reliably making really nice welds (like in the beginning of the video) on flat joints, why do you assume you can do so with tubing?Post up some outside corner joints and fillet welds (inside corner) with flat stock and get help dialing in your technique - then tackle some scrap tubing until you know you can nail the weld on you project.Important rule - never practice on your actual project - hours spent perfecting a weld on scrap saves you hours of frustration trying to fix your project.
Reply:There ya go, exact same issue I have with the tubing, and the casting.  Even with a very fine point, the weld pool will just barely start but immediately the arc starts to scatter and just melts the whole piece if it's thin, the thicker pieces this black crud just floats on top of the pool preventing any sort of control of the pool.  And what is all that black crud?
Reply:I was mistaken about your 165i being a tranny tig. It is inverter.The black smut indicates to me that air is contaminating the weld. Are you running too much argon?Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Originally Posted by MattstrikeThere ya go, exact same issue I have with the tubing, and the casting.  Even with a very fine point, the weld pool will just barely start but immediately the arc starts to scatter and just melts the whole piece if it's thin, the thicker pieces this black crud just floats on top of the pool preventing any sort of control of the pool.  And what is all that black crud?
Reply:I've tried 10, 12, 15, 17, and 20 CFH.  I haven't been able to correlate the smut to any specific CFH.  I've also got a different tank this weekend (exhanged), and seeing the same thing so far.
Reply:Then maybe the regulator is faulty or there is an air leak in the lines or at the torch fittings.  Check the parts on your torch---back-cap, collet, collet body, teflon insulator, cup, power/gas hose fitting.  If any one of those are compromised, it could very well easily be the source of the problem. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:This is 16 gauge aluminum, using the 1.5% lanth, fresh ground point, 15CFHTop to bottom:45A60A75A90A105A120A135AAt the 100+ amp level it nearly instantly melts the entire piece.
Reply:What is your cup size again? If the number is burned off, measure the ID.You pix look like a gas issue. Sometimes the cap blocks off the gas flow and leaks at the o-ring on the backcap. Make sure the collet body is seated finger tight. Look at the collet itself and see if it is crushed. Look inside the threads with the backcap off and try to see the gas hole/port. It should be clear. Then load all of the parts and the backcap, and remove the cup, then collet body and collet. Look into the threads again from this side and try to see the gas hole/port. It will flow gas up to halfway closed off, but no more. If it is choked off you have a problem.So check those things and report back with your findings and the cup size and we can give you a flowrate. I check mine at the torch to see if it matches with the flowmeter on the tank with a portable flowmeter.  They cost $29 and ROI is relatively quick. To see what the surge looks like is shocking.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Cup size is 7.  Flowmeter might take a few days, between work and the supply shop not being open on weekends.  I know gas is flowing at some amount as I can dip the torch in the nearby water bucket and it does bubble quite a bit.  But I'd never disassembled the torch yet so I'll start there.Another possibility is stick out. How far do you have that electrode out from the cup edge/opening?
Reply:Originally Posted by MattstrikeCup size is 7.  Flowmeter might take a few days, between work and the supply shop not being open on weekends.  I know gas is flowing at some amount as I can dip the torch in the nearby water bucket and it does bubble quite a bit.  But I'd never disassembled the torch yet so I'll start there.
Reply:Originally Posted by turismolover22Another possibility is stick out. How far do you have that electrode out from the cup edge/opening?
Reply:Im curious to know if you've been able to resolve your issues heading any of the advice given here. Shovelon's trouble shooting guidance has given me much intel to keep for future reference (thanks), sounds like it may be on par with what you've been describing.  Please let us know.GarLincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:Please slow down and do some more learning before you try and make a mess of someones elses parts. So far I have not seen any signs of a good weld, including your ss.
Reply:I haven't had a chance to take anything apart, but I have since welded a test piece of stainless and mild steel, and still no problems there.  I've been working away from home the last few weeks with limited time at home, and will be for a few more weeks, so I just haven't had time to get back to it with the attention it deserves.   Though I found out that if I accidentally leave the valve cracked on my 40CF tank, when it's hooked up to the welder, all of the gas leaks out overnight.  Originally Posted by kkustomzPlease slow down and do some more learning before you try and make a mess of someones elses parts. So far I have not seen any signs of a good weld, including your ss.
Reply:Matt,That last piece of Aluminum shows a 100% gas issue.   It's just not as noticeable on SS or MS.  Get yourself a bigger tank now.  It will virtually pay for itself by lower refill costs.  Look for one without a named ring around the top near the valve.  That matters in many areas of the country (not mine one bit).  Post a pic of your torch setup in exploded view.  I'd like to see how you have the collet in, blackcap on, etc...
Reply:Originally Posted by MattstrikeI haven't had a chance to take anything apart, but I have since welded a test piece of stainless and mild steel, and still no problems there.  I've been working away from home the last few weeks with limited time at home, and will be for a few more weeks, so I just haven't had time to get back to it with the attention it deserves.   Though I found out that if I accidentally leave the valve cracked on my 40CF tank, when it's hooked up to the welder, all of the gas leaks out overnight. You can see the heat effect zone and the backside of the workpiece in that one picture I posted of the SS after it was ceramic coated?
Reply:I didn't notice anything in the torch that seemed damaged.  The end cap O-ring looked good.
Reply:It looks to me like your tungsten is too far away from your work piece; you getting a wide-spread-cone arc that giving you those huge black melt ins... black because your shielding gas doesn't extend all the way to the end of your long arc.  Tighten up on your tungsten to work piece distance... should only be about 1/16 inch.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet