possible sources of contamination?

admin

A few weeks ago I picked up an Eastwood TIG welder (yeah, I know) for cheap. I have MIG welded in the past (and have a 115V MAC MIG welder that was made by Miller). Of course I've always wanted to be able to weld aluminum so I figured this was a chance to start.I bought 1/16 and 3/32 tungsten and thoriated tungsten (WeldCraft) and Harris 4043  and ER70S-2 filler in 1/16 and 3/32. I bought an 80 CF bottle of Argon from Keen Compressed Air. Got some 6061 scraps and tried laying some beads. Had problems dipping the tungsten, went through some electrodes. Got a little better at keeping the electrode uncontaminated. Tried some DC steel welding, made an okay bead. Aluminum was a different story. Cleaned the aluminum with a dedicated wire brush, turned the balance up, turned it down, added more Argon (up to 25 CFH), no matter what I did, the bead ends up with pepper specks in it, and no etched zone around the bead.I took the aluminum I was welding up to my buddie's shop and had his welder lay down a few beads, then ran one myself (no stack of dimes but it looked like a bead, no contamination, nice etched zone).Home again, I hooked the welder right up to a 60A breaker in case I was starving it. About 1 out of 30 tries I can get something approaching a bead, most of the time I can't even really get a puddle going, the arc is so unstable.I returned the Eastwood welder and bought a used Miller 200 Syncrowave. Pretty much the complete Runner package with the 150A WeldCraft air cooled torch. When I picked it up, the seller ran some nice AC and DC (aluminum and steel) beads with it. I sat down and ran a bead, again, not like the pro welder, but a bead. He seemed to be surprised that I could weld at all.Bring the unit home and I'm having the same intermittent results. I did one 3/16 fillet in aluminum that turned out okay, but on other beads (on the aluminum we were welding on at the seller's shop) I see pepper flecks in the bead. I take a brand new green 3/32 electrode, ball the end with 180A, post flow 7 seconds (the electrode is not discoloring), anywhere from 20 to 35 CFH (#7 cup). I installed a dedicated 60A circuit for the welder so it's not a power issue.The only thing I have not tried is cleaning the filler rods with acetone, but they are not dirty coming out of the tube. I did ask the pro I bought the Miller from about cleaning the filler, he said he does not and does not have a problem with it.I suppose it is possible that the Eastwood welder was not the POS (at least for AC) that I thought it was. Still I'm glad I got the Miller, but I need to figure out what is going on here. Although I am not a welder, I'm a moldmaker/machine designer/CNC setup/CNC programmer/manual machinist, etc., well suffice to say I've been in manufacturing for a long time and have plenty of experience troubleshooting processes.Anybody ever got a bad tank of Argon?Any other things I can look at?Thanks in advance to anyone who takes pity on the newbie.JoeLast edited by scudzuki; 01-24-2012 at 08:30 PM.
Reply:Just wipe the filler with your glove.  If it shines more, then it needed it. I have had contaminated filler.   The puddle gets dirty just when adding filler.  Black dots mean turn the + wave up more.  I usually run it about 30%. less if my stuff is really clean, more if not or welding cast.  What ever it takes to keep the black spots away.DavidI have read here of contaminated or mis labeled gas bottles, but never had it happen to me.Drafts can screw  me up and aluminum likes a lot of argon, like 30 cfh. and a big 8 or so cup.  I use a gas lens when I can.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Newbie ignorance here, what is a gas lens?The AC balance is at 6.5, right where it was when I welded on the same peice of aluminum at the seller's shop.Only difference is 100 miles southwest, different filler, different bottle.WRT contaminated filler, jeez, what are you supposed to do if you can't trust the consumables? Bad gas I can see, but bad filler rod? I have some 1/16 filler purchased in a different order, I can try that. And wiping the rod off, that's easy enough. Another thought, when I pull the filler out of the tube, I lay it on my workbench, which is actually a stainless steel food preperation table I bought from a caterer. The table is pretty clean (I clean it with Simple Green) but I suppose it doesn't take much?I hear clean, clean, clean when it comes to aluminum welding but the welder who works up at my buddie's shop doesn't seem to go to much trouble to keep his operation clean and his work is really nice. I guess it's a matter of knowing where to put the effort in?I'll try to add more cleaning to the balance and a bigger cup.Thanks for your help.Joe*edit* I just re-read the manual for my welder and it looks like I'm running at 57% penetration (electrode negative). The total adjustment of my machine, from 0 to 10, is from 50% to 60% EN.Not sure what you mean by 30%. I just tried it at 0 (50%) and it melted the electrode. I tried some of the 1/16" filler with the same results I was having with the 3/32". I put on thean 8 cup and cranked the Argon up to 30. It's now getting worse as I can't even put down a single bead that looks even reasonably clean. I can walk the arc without filler and it looks nice and clean. Now as soon as I add any filler it balls up instead of melting into the puddle. I swear my garage is like some welding black hole.Last edited by scudzuki; 01-24-2012 at 09:58 PM.
Reply:I returned the Eastwood welder and bought a used Miller 200 Syncrowave. Pretty much the complete Runner package with the 150A WeldCraft air cooled torch. When I picked it up, the seller ran some nice AC and DC (aluminum and steel) beads with it. I sat down and ran a bead, again, not like the pro welder, but a bead. He seemed to be surprised that I could weld at all.Bring the unit home and I'm having the same intermittent results. I did one 3/16 fillet in aluminum that turned out okay, but on other beads (on the aluminum we were welding on at the seller's shop) I see pepper flecks in the bead. I take a brand new green 3/32 electrode, ball the end with 180A, post flow 7 seconds (the electrode is not discoloring), anywhere from 20 to 35 CFH (#7 cup). I installed a dedicated 60A circuit for the welder so it's not a power issue.Hey, Joe,Since you used one bottle of gas at the seller’s, then another bottle at your shop, with different bead appearance, it kinda looks like bad gas.  I am one of those, apparetly rare persons, who has had a bottle of contaminated gas, which resulted in bead appearance that you describe.  Suggest bringing another bottle of gas to your shop, keeping all other conditions the same, to see if it makes any difference.
Reply:Yes, sounds like bad gas. I encountered the same issue a few weeks ago. I had a fresh bottle of argon. It would arc and puddle but when filler was introduced it would ball, blacken. Turns out, the argon bottle was contaminated. I learned from LWS rep that if the empty bottle is not properly evacuated, purged prior to refill it leaves moisture in the bottle that cooks off when welding, producing oxygen. Get a new bottle of argon.Miller TrailBlazer 251Miller HF-250-1Miller MaxStar 150 STLHyperTherm PowerMax 380 plasmaLincoln PowerMig 180Millermatic 252Miller Diversion 180
Reply:I'm replacing the bottle today.I'll report the results later.Thanks all.Joe
Reply:HII had a problem and thought it was gas so I ran a test.  Good clean aluminum plate run a bead in the middle of the plate without a rod just running a puddle.  Run it about 1” to 3” long and look at it.  If its clean you gas is ok. have funTom
Reply:scud,Not trying to sound like a wiseazz, but did you really think you'd just pick up a tig welder and start laying dimes right away?There's a reason most tiggers will tell the newbie's that they're best learning the basics on mild steel vs aluminum.  Mild steel is much more forgiving than aluminum.Without looking over your shoulder, I'm guessing you're melting the filler with the arc, rather than dipping the filler into an already existing puddle.  The other thing I'd bet on is you're holding too long an arc.Filler control with aluminum is also more critical with aluminum than it is with steel.  It's a fine line you walk between moving the filler too far out of the gas coverage (that will contaminate the filler) and melting the filler before you get it to the puddle.On the Syncrowave machines, I tend to run a balance setting of around 8.If you're he11 bent on working with aluminum before you've learned the basics of tig with steel, then at least start with forming a puddle and moving it across the coupon without adding filler.  This will help with the puddle control.  You'll find yourself backing off on the amps as heat builds in the coupon.There's a lot more "going on" with tig than it is with a squirtgun.  Improper technique in any step will generally result in a lousy weld.Learn to walk before you enter the marathon.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:Gas is not the problem.Replaced the bottle, same results.Jester, I can run a puddle without filler and it looks fine, as I posted last night.Sundown, of course I did not expect to weld well right from the git go.I realize it's not easy, otherwise people would not have to go to school and weld a mile of beads before becoming proficient.Thing is, I sat down and ran a bead no problem with the machine setup at the seller's shop.I sat down at my buddy's shop and ran a bead no problem.I have also successfully run a bead since it's been in my shop. Last one I did before I started having this inconsistency was not dimes but spare change. Nothing but inconsistency since then. Yesterday I put in a 60A circuit and changed out the factory power cord. The OEM cord was #8, I put in a 25 ft #6 cord to reach the receptacle. I soldered the ring terminals on the wire. While I had the side cover off, I blew out a mountain of dust. Today it won't even start an arc reliably. I suspect that when I blew the dust out of it with compressed air, some ended up on the HF start coils so I'm getting ready to check the gap and make sure there's no crud settled on the contacts.I'm trying to get someone with a clue to stop by my shop and test it out, too, but Haven't had any luck there.Joe
Reply:Let us know what you find out with the gas. I agree with Sundown. Watch carefully of what you are doing. I am really new at learning myself (only a few days). One of my biggest problems is melting the filler with the arc and not the puddle. Things I caught myself doing. The good thing is that at least I am learning enough to recognize what I am doing wrong. Now if I can just stop doing it (LOL)...Not enough Tungsten StickoutMelting filler with the arcToo long of an arcForgetting to turn on the gascontaminated tungsten and not switchingnot enough angle on the tungsten when sharpeningHobart Handler 210 with SpoolgunHypertherm PM30 PlasmaHTP 221 Tig WelderHF BandsawHF Auto Dark Helmet
Reply:Mikeb,It was not the gas. Different bottle, same results.As for your list, been there, done that, I'm sure I'll be back for more.WRT angled tungsten, you are talking about DC, yes? Seems like AC just melts pointed electrodes and I end up with the ball.If I ball it  first, it seems to stay that way with little wear.HF start fixed.Took both side panels off, blew the rest of the dust off, especially the HF unit, checked the gap. Fired it back up with the side panels off, ran it until the fan came on, checked my new power cord and soldered on ring terminals with an IR thermometer, room temperature. Power is okay.Put the side panels back on and found a short piece of 1/4 x 1-1/4 aluminum angle. Started the arc, waited for the puddle to grow past the arc, then walked a bead. Stack of dimes, nice etched zone, no contamination. Not perfect, but a starting point.Apparently the advantage I had following the pro welders when I ran beads at their shops was, I watched what they did and tried to emulate it, with decent success. Filler goes in the puddle, not the arc, I'll not forget THAT again.I figured out why I have been having such trouble... the tubing I have been practicing on is only 1/8 wall. I can't get the puddle to grow past the arc so I can start adding filler without the base metal melting and collapsing. In other words, I can weld thicker materials, but cannot finesse thinner stuff yet. The thicker material is just more forgiving.Maybe I'll weld some steel for a while just to get a hang of the torch/pedal/filler coordination, especially torch speed. When I started, I figured I'd start on aluminum b/c it's harder to do but apparently I've bitten off more than I can chew. For now.Thanks to all for the wisdom of your experience.JoeLast edited by scudzuki; 01-25-2012 at 04:22 PM.
Reply:Glad to hear it. The reason I started on aluminum is that scaps don't have rust or paint. Lots of paint removal means more grinding time and less arc timeHobart Handler 210 with SpoolgunHypertherm PM30 PlasmaHTP 221 Tig WelderHF BandsawHF Auto Dark Helmet
Reply:The welder I bought came with some spare torch parts such as cups, collets.Only 3/32 collets, though, so I have not been able to run any 1/16 tungsten.I have some on order, though.If I can run 1/16 tungsten, will that give me a smaller, more focused arc, that could result in the puddle growing enough to lead the arc in thinner aluminum, without the base part melting through? Maybe this is why I am having problems with thinner aluminum, the thicker arc that comes off the 3/32 electrode.Maybe.Any of you experts care to weigh in?Joe
Reply:1/16" tungsten is really too small to do 1/8" alum. 3/32" is the recommended size according to Millers tig calculator, and the tech school uses 1/8" tungstens to teach alum.One of the biggest issues new guys have with alum is they don't use enough amps and try to ramp up slow. Alum is a terrific heat sink. It will suck heat away from your puddle heating up the whole material. By the time you get the puddle up to temp, lots of time a huge area is almost at temp also, and all of a sudden the whole thing caves in. Not cleaning off the oxide layer makes this even worse, as the oxide layer melts at a higher temp than bare alum.For 1/8" alum you want the machine set to at least 150 amps. Stomp on the peddle and give it all it's got to get the puddle running fast, then back down and move quickly. Heat control will be key, and you have to anticipate and do things almost before things start to go south to correct for issues.That's why steel is a better choice. It's much more forgiving as far as heat and speed is concerned. You can take your time and back down as needed to keep things under control. When things start to get out of control with alum, you usually need to go faster, not slower, and as a newer welder you simply don't have the instinctive actions down yet to do this..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:I hear you on ramping up, I've been easing into the pedal.Also, definitely having a problem with torch speed.I need a lower table to be really comfortable.Have to get a welding area setup, with a proper table, seat, and vent hood.JoeMiller Syncrowave 200Mac/Miller MW130 MIGKalamazoo bandsawCincinnati Arrow 500 VMCColchester Dominion 15 x 36 lathe with 2 axis DRO
Reply:Ditch the pure tungsten with big axx ball--whichspreads the heat; focusing the heat via thoriated, ceriated, etc. and a sharp point.Additionally run fully unbalanced--set for max. pen. Massive, focused heat succeeds where other methods fail;this bears out on thick & thin AL.Last edited by dave powelson; 01-25-2012 at 06:38 PM.Reason: correctionBlackbird
Reply:Dave,   I'll try your recommendations. Despite conventional wisdom that says pure tungsten with a balled end for aluminum, I keep hearing "use pointed thoriated (ceriated, lanthanated, whatever) tungsten for aluminum". Matter of fact I think I was using pointed thoriated when I tested the welder on aluminum before I bought it.I tried using a 3/32 thoriated electrode on aluminum today, without pointing it. First I tried to ball the end. It barely melted at 200A. Definitely stands up to heat much better than straight tungsten.JoeMiller Syncrowave 200Mac/Miller MW130 MIGKalamazoo bandsawCincinnati Arrow 500 VMCColchester Dominion 15 x 36 lathe with 2 axis DRO
Reply:Originally Posted by scudzukiDave,   I'll try your recommendations. Despite conventional wisdom that says pure tungsten with a balled end for aluminum, I keep hearing "use pointed thoriated (ceriated, lanthanated, whatever) tungsten for aluminum". Matter of fact I think I was using pointed thoriated when I tested the welder on aluminum before I bought it.I tried using a 3/32 thoriated electrode on aluminum today, without pointing it. First I tried to ball the end. It barely melted at 200A. Definitely stands up to heat much better than straight tungsten.Joe