First time TIG welding - Aluminum - looking for advice

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Hello... I fired up my Lincoln 175 today for the first time... this is going to be a rough post, looking for some advise... Thanks in advance. My 2 second background. I MIG on a daily basis with a Miller 251 for last 5+ years. I am self taught. I MIG steel and stainless from .065 wall tubing to 3/8 plate/flat, etc. I bought a (near new) Lincoln 175 TIG machine afew years back because it was a good deal, but never really used it till today. I attached pics of my settings. First time today, only played with it for about 30 mins... I’ve been reading the web and you tubing to get an idea... gotta start somewhere. Material was .083 aluminum tube. Using 4043 filler. Aside from the settings I used and would like advise, my main question is with the tungsten. I used Red. I was under the impression, it should be pointed (I filed down to start). It only took a second to turn into a ball though? Length from cup wrong? Also, I was never able to get a clean arc. It was more of a "field/array" from the tungsten. Assuming because it was balled?Anyhow... I've got a handful of other questions... Please critique... I've got thick skin, lol. Thanks, BTW: I also have a pulser for the machine. I choose to not use it, until I get a grip on some basic settings.MY GOAL... I'd like to be able to weld .083 aluminum tube and up to 3/8 inch flat stock (if the machine can handle it).
Reply:2%Th tungsten won't handle AC current like 1.5%/2% Lanthanated will.  The Lanthanated tungsten will stay quite sharp (so long as you are using the appropriate sized tungsten to begin with), forming only a tiny ball at the end.  This allows better arc control, instead of the "wide shower" arc you're seeing with a ball the diameter of the tungsten.Second, don't wire brush the welds after you're done.  A weld bead "as is" left untouched after it is completed tells a lot about the whole process in general and you will get even better advice.3/8" is a tall order for 175A.  3/8" = 0.375".  If the piece is large (which would sink heat out quickly) you'd need 375A+ of current.  1/4" typically calls for a 300A+ machine in order to not exceed the duty cycle too often.  Unfortunately I do not believe this will happen with your 175A machine.Also if that is the only piece you have to practice on, try to weld towards the middle of the tube instead of towards one end of it.  As you reach the end, the end will become super-heated and will start to droop-out because the whole end-piece quickly approaches the melting point instead of just the area the arc is concentrated on.  Also make sure to cool the piece prior to running the next bead to avoid having residual heat act as "more current" and changing one aspect without you even knowing it.Last edited by Oscar; 06-12-2014 at 07:00 PM. 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:I just started tig myself with aluminum. I learned really quick its a very pickey metal abd it's a fast pace weld. It.likes to be clean butYou can't clean it with anything but a stainless steel wire brush. Id also get a flat piece of alum. To weld on. I'll be flirting this thread for more advice also! Good luck! Sent from my SCH-I535 using Tapatalk
Reply:Your machine is a solid 1/8" tig on alum. 3/16" would be pushing it beyond it's output. AC tig has tendency to "wander" especially at low amps. 1st thing we need is your machine settings. Since alum is such a great heat sink, you need to hit it hard with a lot of amps so the material doesn't wick away the heat. With small pieces it can fool you since the piece rapidly heats up until you hit welding temp. However at that point you have removed all the temper from the piece and the puddle can be very uncontrollable.For 1/8" you want the machine set no lower than 150 amps. I'd have your machine maxed myself for 1/8". For .083 I'd be in the 125-150 range and use the pedal to back down as soon as I got the puddle to form. AC tig is NOT easy. It takes a lot more heat control than say steel tig does..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:Thanks for all the fast replies!I heard that 1.5%/2% Lanthanated is better for what I'm doing... I was limited on supplies today, but plan to switch. I had a feeling the machine was too small... you brought up an interesting point about the size of the work though and heat sink out. I would mostly be welding tubing (14 ga) lap welds. The larger solid stock sizes that I plan to weld would be in the form of "tabs/ears" welded to the tube. It would be flat stock like 2/3/4 inches. Although, they would be upwards of 3/8 inch thick, they would be rather small themselves. Not sure if that would make material heating better or worse with this machine?I was using 110amps today. I noticed when I pushed the pedal about 1/4 way, the arc seemed "clean-ish" but did nothing on the material. When I got about 3/4 way on the pedal, the arc was much more of an array and not too defined, other than the field itself. I was thinking it would be defined? Is this because aluminum acts different? It did however heat the material at this point. I waited until the puddle was clean (2-3 sec) and started to move. It was hard to figure how to add filler because the array was so un-controlled. I kept the filler on the material and just waited till it melted on its own (on the outside of the field), then kept pace. I tried the machine at 150 amps also... and it also worked, but I figured if 110amp worked, then I didnt need the extra power? I guess this is just something I will get a feel for in time. Also... I will admit, I am aware of the general prep/cleaning process... I was just starting today and didnt have all the materials. Wire brush was steel (probably even had debris in it). The aluminum tube itself, as well as the tank of argon and also the actual 4043 rod were easily 1-2 years old sitting in the shop (a steel shop). I know this probably didn’t help either. Thanks again for the insights, I'll keep reading and get some better supplies then post new pics.
Reply:IDK, I use a 1/8" Red (Thoriatied) for AL, and have pushed it pretty hard without forming an ball too quickly on the end. I was blowing holes in 1/4" AL to test the higher end of the medium setting on my old welder (330a-bp). I'd guess the amps to be in the 240 range, not too far from your max. My daughter enjoyed this to no end (Lets' do that again dad!)!I use it pointed and it does ball somewhat, but not that fast. Usually i screw up by dipping before it balls.Looking at your pics, at least one of the pipe welds (the one with the sagging/blowout on the end), looks like the aluminum got saturated, then sagged otu. This is the result of too low amperage.I'd try to hit it at max, then backoff as it heats. You'll figure it out pretty quick as you have experience watching the puddle.Make sure preflow and post flow is good on the argon. Poor gas coverage will screw up the arc for sure.And, if you dip it, regrind. Make sure you regrind radially, not axially. Radial regrind can cause wander.There is a good comparasin here:http://www.weldingtipsandtricks.com/...lectrodes.htmlChay
Reply:I assume you mean axial wander, not radial.Jerry30+ yrs Army Infantry & Field Artillery, 25 yrs agoMiller 350LX Tig Runner TA 210, spool gunLincoln 250/250 IdealArcESAB PCM 500i PlasmaKazoo 30"  vert BSKazoo 9x16 horiz BSClausing 12x24 lathe20T Air Press
Reply:Originally Posted by Big_ChiefI was using 110amps today. I noticed when I pushed the pedal about 1/4 way, the arc seemed "clean-ish" but did nothing on the material.
Reply:Are your leads reversed? Your machine is preset at 70% balance DCEN.  If they are reversed your tungsten will ball back like that.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:We were advised to grind our Th-2 tungsten steep (and not rounded on inverters) with a decent land at the tip when we practiced on smaller stuff at school.  It might translate up to the current you are using.  We were using close to that current on ~1/8 material though (with a controller).
Reply:Originally Posted by storemanI assume you mean axial wander, not radial.Jerry
Reply:Originally Posted by shovelonAre your leads reversed? Your machine is preset at 70% balance DCEN.  If they are reversed your tungsten will ball back like that.
Reply:Originally Posted by Oscarunless I'm thinking about it incorrectly, AC is AC.  Switching the leads won't change 70%EN to 70%EP because we're talking AC.  If it were DC, then yes it's completely different where DCEN at the torch would be switched to DCEP.
Reply:Oh ok, gotcha!  I just wanted to see if you were paying attention Soutthpaw!  Good job! you pass the test!   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:Originally Posted by OscarOh ok, gotcha!  I just wanted to see if you were paying attention Soutthpaw!  Good job! you pass the test!
Reply:Originally Posted by OscarOh ok, gotcha!  I just wanted to see if you were paying attention Soutthpaw!  Good job! you pass the test!
Reply:Thanks for all the replies... So I finally had time to get to a LWS. After this post, I broke down the gun and found the gas lens was shot. Clogged with spatter and age (it had been awhile since I cranked that machine up).So I got some 3/32 1.5% Lanth, along with a new 3/32 gas lens and 3/32 standard gas. Some new cups #6, and other misc items. I was back at the table today with the same .083 AL tube. This time with new supplies. AND I cleaned it better (SS brush and Acetone). The "un-controlled" affect of gas, was solved. I set the Argon at 15 cfm. First I used the regular gas nozzle, #6 cup and 1/16" 2% thor. Made afew passes and got a decent bead on the 4th shot (the pic with the BLACK end spot). I did start to develop a ball at this point though. Machine was set at 150 amp.Then I went to the gas lens, #6 cup and 3/32 1.5% Lanth. It did seem to maintain the tip better without balling. Made about 8 passes this time. Machine was set around 135 amp.Please crtique. Afew questions also. Other than a chart, whats a good rule thumb to visually tell if your undersized/oversized in tungsten... and filler?I read alot about pre-flow and post flow. I understand what it means, but does my machine support that? I have a Linc 175 SW. Only have amp control and AC/DC settings... how would I make this happen? (see the top pic I posted of the machine).Afew replies up the thread, someone mentioned the leads being reversed. Is this "inside" the machine? I only have 2 wires on the front of the machine... (see top pic I posted of the machine). Finally, what is a good way to end? I know this is the purpose of the post flow step... in the one picture, you can see how the black spot developed... or a crater develops? I'll keep tinkering in the meantime... atleast I'm getting somewhere now. Thanks again. Please let me know if my tungsten/torch settings seem in line.
Reply:Black like that almost always means you fouled the tungsten and need to regrind to clean off the fouling. Alum wicks a lot farther up the tungsten than steel does, so you really need to do more work making sure you clean the tungsten well.Filler size, always try to go smaller than the base material thickness.  You can weld thicker material with smaller filler, you just have to dip more. I know plenty of guys who stick to just about one filler size, usually 1/16" or under and use it for just about everything. They just vary the amount and number of dips to suit the material thickness they are welding. Tungsten size is a bit tougher. A lot of the answer depends a lot on what you are welding and the amps you are running. Especially with AC it's easy to tell if the tungsten is too small. It balls up really big as the DC + "attacks" the tungsten. Around 150-180 AC I tend to swap between 3/32" lanthanated and 1/8" on my syncrowave. The bigger tungsten holds up better over time, and doesn't ball as much. The smaller tungsten though gives me a bit more control over the arc. On things like outside corners, where I want more control, I tend to go smaller. When I'm doing fillets and tend to use more amps, I go bigger. Steel, almost everything I do can be done with 3/32". 1/16" would probably work for 80% of the stuff, and if I tended to weld more thin material, I'd probably drop down to it over 3/32". With more seat time you'll begin to notice how the arc acts and understand this a bit better..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:If I weren't on a new puter I could fill this thread with aluminum projects well over 1/8" thick that I have welded with my lincoln 175 (same machine).That is a great machine and will give many many many years of great trouble free service.I gree the 3/32 tung will give problems welding especially for long times on aluminum. You will notice this quick while welding the tip of the tung will start to melt and wiggle. Even still I do pretty much all of my welding with 3/32.From the looks of your welds you have a pretty decent handle on what you are doing already, just keep weldin and it will all come together.