Unstable arc on aluminum

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What are some causes of an unstable arc while tigging aluminum. I wire brushed and cleaned with acetone.Will   Supports Autism Awareness                            My ToysBobCat 225 PLusMillermatic 130Miller Spectrum 300 CutmateEverlast Power Tig 185 Micro April is Autism Month .
Reply:Tungsten not prepared right. To low amperage. Bad ground. Wrong shielding gas. Machine not set on ac. Just to name a few1973 Lincoln SA 200, Already replaced shunt coils, Idle board (SOLD)1984 Miller Dialarc 250HF, Miller water cooler, 250 AMP water cooled torch, you know the worx.
Reply:I thought that was "standard" on the Chinese welders.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:Originally Posted by SundownIIII thought that was "standard" on the Chinese welders.
Reply:Originally Posted by TuscanyTungsten not prepared right. To low amperage. Bad ground. Wrong shielding gas. Machine not set on ac. Just to name a few
Reply:I use the orange ceriated sharpened to a point.  Have you welded aluminum before?  The arc is quite different.Last edited by 1grnlwn; 03-29-2012 at 08:34 AM.
Reply:Originally Posted by 1grnlwnI use the orange ceriated sharpened to a point.  Have you welded aluminum before?  The arc is quite different.
Reply:Yah your supposed to sharpen it to a fine point then ball the end of the tungsten by putting machine in dcen and striking an arc on some steel if I remember correctly some one feel free to chime in and correct me if I'm wrong the last time I tig welded was about 7 years ago but when I did do it I was quite proficient at it.1973 Lincoln SA 200, Already replaced shunt coils, Idle board (SOLD)1984 Miller Dialarc 250HF, Miller water cooler, 250 AMP water cooled torch, you know the worx.
Reply:Have any pictures of beads you've tried?Given a clean, ground right tungsten and clean metal;Are you getting the proper cleaning action around the bead(frosty white etched area from DCEP cycle, usually a few mm or larger around the bead) or just a very thin greyish-black area instead?    What about the arc itself. Are you getting a focused "cone" of argon plasma  with the tip coming from the electrode or is it more of a thin, jumpy, wisp of an arc that acts as if it's hunting for a conductive spot through the Al oxide to the base metal? Normally the DCEP part of the AC cycle vaporizes the Al oxide layer. If this process isn't going well I've gotten arcs that will try to "stick" to parts of the metal where it's managed to break though versus closely following the electrode's movement.I was having a similar issue and it turned out being Ar cylinders that were probably left open at 0psi and filled later with moisture still in them. Water vapor will dissociate in the heat of the arc and leave you with oxygen contaminating the weld.For a fun test I ended up putting a gas dryer on one of the "bad" cylinders after testing with a known good cylinder and it cleared right up. Desiccant ended up turning pink after a little bit indicated water vapor HTP Invertig 221-DV -- get's dragged everywhere.Syncro 200 -- "The Boat Anchor" at the lab.Lincoln 125 MIG
Reply:Originally Posted by Commodore8888Have any pictures of beads you've tried?Given a clean, ground right tungsten and clean metal;Are you getting the proper cleaning action around the bead(frosty white etched area from DCEP cycle, usually a few mm or larger around the bead) or just a very thin greyish-black area instead?    What about the arc itself. Are you getting a focused "cone" of argon plasma  with the tip coming from the electrode or is it more of a thin, jumpy, wisp of an arc that acts as if it's hunting for a conductive spot through the Al oxide to the base metal? Normally the DCEP part of the AC cycle vaporizes the Al oxide layer. If this process isn't going well I've gotten arcs that will try to "stick" to parts of the metal where it's managed to break though versus closely following the electrode's movement.I was having a similar issue and it turned out being Ar cylinders that were probably left open at 0psi and filled later with moisture still in them. Water vapor will dissociate in the heat of the arc and leave you with oxygen contaminating the weld.For a fun test I ended up putting a gas dryer on one of the "bad" cylinders after testing with a known good cylinder and it cleared right up. Desiccant ended up turning pink after a little bit indicated water vapor
Reply:Check your HF point gap. I've had new machines not set right from the factory(Miller) that cause unstable arcs. Also the Everlast has an extra ground conection to help with HF problems."ALL DAMAGE, NO CONTROL"
Reply:NO need to ball ceriated.  Try different aluminum.  Ac arc is pretty loud and violent compared to DC.  It takes a while for heat to build in metal.  You will see the surface under the arc mosaic then the AL will turn shiney which is your puddle.
Reply:FYI - No balling on inverter machines. No green tungsten on inverter machines as well.Try some red. I never had good luck with orange at all.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Originally Posted by SundownIIII thought that was "standard" on the Chinese welders.
Reply:Originally Posted by TuscanyYah your supposed to sharpen it to a fine point then ball the end of the tungsten by putting machine in dcen and striking an arc on some steel if I remember correctly some one feel free to chime in and correct me if I'm wrong the last time I tig welded was about 7 years ago but when I did do it I was quite proficient at it.
Reply:Originally Posted by TuscanyYah your supposed to sharpen it to a fine point then ball the end of the tungsten by putting machine in dcen and striking an arc on some steel if I remember correctly some one feel free to chime in and correct me if I'm wrong the last time I tig welded was about 7 years ago but when I did do it I was quite proficient at it.
Reply:SUNDOWN gonna get ya! make ya kick your dog and lose a whole nights sleep! I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Originally Posted by weldermikeSUNDOWN gonna get ya! make ya kick your dog and lose a whole nights sleep!
Reply:Originally Posted by Steelwill...is there a certian way my tungsten should be grounded other than what I have been reading.
Reply:Well I think I may have it I kicked up the amps and played with the balance controlWill   Supports Autism Awareness                            My ToysBobCat 225 PLusMillermatic 130Miller Spectrum 300 CutmateEverlast Power Tig 185 Micro April is Autism Month .
Reply:After the first beads I turned up the frequency  and turned down ac balance.Will   Supports Autism Awareness                            My ToysBobCat 225 PLusMillermatic 130Miller Spectrum 300 CutmateEverlast Power Tig 185 Micro April is Autism Month .
Reply:Lookin good there. Definitely moving in the right direction.I'll let someone more experienced speak about the craters atthe end Glad your getting it though. Keep at it and enjoy learning along the way!edit:  +1 for the autism awarenessHow do you know the blacksmith's dog? When you hollar at him he makes a bolt for the door!
Reply:Originally Posted by that'll_buff_outLookin good there. Definitely moving in the right direction.I'll let someone more experienced speak about the craters atthe end Glad your getting it though. Keep at it and enjoy learning along the way!edit:  +1 for the autism awareness
Reply:Originally Posted by SteelwillYeah that's going to be the  next question whats causing the dimple at the end.
Reply:Originally Posted by SteelwillYeah that's going to be the  next question whats causing the dimple at the end.Originally Posted by 1grnlwnNO need to ball ceriated.  Try different aluminum.  Ac arc is pretty loud and violent compared to DC.  It takes a while for heat to build in metal.  You will see the surface under the arc mosaic then the AL will turn shiney which is your puddle.
Reply:Originally Posted by that'll_buff_outLookin good there. Definitely moving in the right direction.
Reply:Originally Posted by WeldordieAhem... judging from the photos, OP is moving in the left direction.
Reply:Originally Posted by RojodiabloWith many who start welding aluminum, they start out trying to weld it like steel; more precisely, they try to weld it a lot like Stainless Steel. Nothing could be further from correct.If your arc is erratic, you are simply not hitting the pedal hard enough on start up. Aluminum does not form a clean arc at low low amps the way steel will. Take the old rule of thumb chart, and add 10% to it. If it's .125 steel, max amps would be set at 120-125 amps. The ACTUAL amperage used will likely be a lot less..... like 80-100A. Now, for the same thickness aluminum, set the max amps to say 130-150. And, when you start your puddle.....FLOOR it. Then back it off. You will see a puddle form RIGHT NOW, and this is what you want. Modulate amps with the pedal. There are a lot of settings to work with on most inverters, so I will give you the basics for what works well on almost any aluminum welding- most of this is basic stuff: AC, balance 70%, Frequency between 70-105, preflow 1 second, postflow about 7 seconds (Any more is not really necessary). 2 step function, not 4 step. Does your machine have upslope and downslope? (Might be called 'Soft start', Soft stop' feature.) This is NOT desirable for aluminum welding. Set it to like .1 second, or zero. You see, with SS, steel, and Ti- oxides form slowly, and the material absorbs heat locally; you can often touch a welded tube within 6 inches of a small weld on SS. BUT...aluminum wicks away heat. Aluminum tends to resist allowing an arc to form cleanly. (Hence why you must go up a wire size for  aluminum house wiring; more resistance) To really form a puddle, and get a strong initial arc, you need to ramp up the heat rapidly. The arc forms, and pushes out the oxides as the puddle washes the surface. If you do this slowly, with low amps...... you just make lots of oxidation right where you want to weld- which is not helpful.To close the crater at the end, Zap gives the best description of how to finish them off well. To the effect of "Wind down the weld, and lift off the pedal. The crater forms.... now step the pedal again halfway, get a quick arc, and dab one shot into the crater/ puddle." It does not always work out exactly how you want it to, but you will be much closer, and the extra dab WILL help the strength of that weld stop.Good luck.
Reply:Don't listen to the China haters, I'm sure your machine isn't the problem. Aluminum is a whole new world of welding. I'm no expert but preheating helps me get started. Once. You get going there's plenty of heat there. Ps, the sundowners of this forum have their own style but they can also be a wealth of info and experience. I try to ignore the meanness and extract the valuable info.Miller diversion 165Miller mig 211Hypertherm pm 30Milwaukee 6230 14 inch chop sawMd 45 mag drill (RIP; fell on its head)New MD 45! Thanks to the esposa!Finally got an O/A setup
Reply:Originally Posted by SteelwillSorry I don't think so.
Reply:Originally Posted by weldermikeNot you Will, the guy with the bad advise!
Reply:The higher the frequency the more stable and focused the arc, ie fillet welds. the lower the frequency the softer the arc ie multiple pass or outside corners. Don't make to many changes at once or you wont know what you have done. Aluminum takes time and a lot of practice it is a totally different animal. keep it up and you will get it.