Need TIG for 1/4" aluminum tubing

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Here's my situation. I have to fabricate a decorative Aluminum structure for a retail showroom. It consists of 4 posts of  8 x 8 x 1/4" Al tubing connected by 3 x 3 x 1/4" horizontals welded to the posts. Currently, I have a small MIG welder for some metal fab needed. I have a 220 single phase circuit available (40 amp breaker). I don't want to spend too much money, but am considering the Dynasty 200dx. Is a 200 amp machine capable of welding 1/4" aluminum ? Any other options ?
Reply:so that's about 8 feet of weld.  it will cost you about 800 dollars per connection. have you considered hiring a welder giving it to a shop?400 per weld; or 800 per 3 x 3.  angle or tube?  not that it matters muchLast edited by fdcmiami; 12-10-2011 at 08:54 PM.Reason: clarification
Reply:Attached is a pdf file showing the structure. There is actually a lot more weld than just theconnections. The size is 10' x 12' post to post with the top structure spanning  178" x 298"
Reply:Here's the image Attached ImagesAL structure.pdf (33.2 KB, 429 views)
Reply:I think my Arcmaster 185 would be just barely big enough.  Maybe some preheat would help with the thick stuff.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:To the OP. Have you tig welded aluminum before. If not, this project is not what you want to practice on esp. for a retail showroom.I had a Dynasty 200DX. Now I have a 300DX. The 200DX might do it, but I do not like to wait for a puddle. Rule of thumb. 1 amp per .001 so you would need 250 amps. I like to get a puddle right away and do not hang around, hammer the pedal get a puddle and go go go, hot and fast with aluminum. If it were me I would run about 270 amps to do this. However the more you weld on the same piece the less amps it will take, thus controlling with the pedal is key.Last edited by TJS; 12-10-2011 at 09:21 PM.www.tjsperformance.comDynasty 300 DXHTP 240HTP Microcut 380Hyperthem 85JD2 Hyd Bender and HF Hyd Ring Roller all in one =(Frankenbender)Bpt. Mill/DRO4' x 8' CNC Plasma TableInstagram: tjsperformanceYT: TJS Welding and Fabrication
Reply:I do have a person that has done TIG welding in his last job. If I do go ahead with this, it looks like a 200 amp welder will be able to do this right at the edge of its capability while a 250amp welder would have no problem. Is that correct ?
Reply:250 would be the better choice.   i have done a lot of aluminum tube construction.  there is not enough info here to even venture a guess as to cost.   one thing i can see right away is life would be a lot easier if you could fabricate that frame work so that somehow it is inside  those uprights, though it probably wouldn't fly with designer.  then it would be a fairly easy job.  for both fab and install.  hope you know what you are getting into.
Reply:200 amps might be find for a weld or two ,but something this big need a 250 or better yet a 300 amp machine with a water-cooled torch. You may want to look at a pulse mig, 6061 tube with 4043 wire might give you weld that looks  good .It would also be a lot faster. WelderbobSound Marine Custom Aluminum Boats
Reply:200 amps is more than enough machine to weld 1/4 inch if you use the right gas and polarity. Helium gas and DCEN for thick aluminum. If you can weld steel, you can do this. Cake.Two turn tables and a microphone.
Reply:Originally Posted by jimcI do have a person that has done TIG welding in his last job. If I do go ahead with this, it looks like a 200 amp welder will be able to do this right at the edge of its capability while a 250amp welder would have no problem. Is that correct ?
Reply:You don't need huge amps, 200 is probably fine with helium/argon mix.Welding/Fab Pics: www.UtahWeld.com
Reply:I appreciate all the reply's received so far. Dave - thanks for clarifying the electrical specs.I have 3 phase available so that is no problem. Based  on the questions so far, here is a  question. If I run a dynasty 200dx, 3 phase at 200amp, helium or helium/argon mix - will this be sufficient to weld the 3 x 3 x 1/4" to the 8 x 8 x 1/4" tubing. Would I be better off welding 3 x 3 x 3/16" to the 8 x 8 x 1/4". While I would want the welds to be visually appealing - the majority of all welds will be 10'-12' above the floor and the entire unit will be powder coated. (Of course the welds have to be strong)
Reply:If the whole thing is going to be powdercoated, MIG weld the whole thing. You'll be a lot happier that trying to TIG it with a little machine. Welderbob
Reply:The 200dx will put out 200 amps on 220v single phase.  Your duty cycle will just be lower.ɹǝʌo ǝɯ lloɹ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
Reply:Heh, I know the OP said its 'decorative' but geez that looks like a lot of welding.  If he wanted to finish this in reasonable time, I would say MIG is the way to go.350P or Lincoln 350MP (I think that's the number)  + spool gun would make short work out of this.  The pulse for out of position welding (or can you flip that thing around?)Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:People are going to walk under this ?DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Hire a professional fab shop to do this job.From the comments/questions asked, it's way beyond your level to do in house.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:I personally would be concerned about my liability if folks are gonna be walking under it.  A whack in the head by a 3X3X.250 is gonna leave a mark no matter what.  If this is your first foray into TIG and Aluminum, you should hire a pro and rely on his insurance as well as expertise.  It will cost less in the long run with a pro just considering the screwed up material wasted from bad welds.  SDIII has the right idea fer sure.  Sorry.BobI'm spending my Kids inheritance, I dont like him that much anyway!!!!!!Enuff tools to do the job, enough sense to use em.Anybody got a spare set of kidneys?  Trade?
Reply:Or you could use DC-  with straight HeliumLast edited by B_C; 12-11-2011 at 10:19 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:A weld prep is advisable for that thickness of material.......Unless you have room for a large radius bead.........  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:if that is only decorative, and not holding up other loads, why not go to 1/8" wall to save a lot of money, time, to be sure a 200 amp inverter will be adequate?miller syncrowave 250hobart handler 140home made 400 amp engine driven in progress...
Reply:are you building this on the jobsite?
Reply:I need to change the title to: MIG welding aluminum tubing. That is the direction we'll be going. As far as the 1/4" thickness...the 8x8 posts will remain 1/4" ( min. available).The 3 x 3 posts will be changed to 1/8". Once I took a look at the weight, we needed to change to make the assembly easier.As far as the assembly method, the 4 posts will be bolted to the floor. The lower pair of railssleeve into the large posts and are bolted. The front and back sections are also sleeved and bolted.The very top sections (front and back) wil sit on top and be bolted down. This way,the sections can be shipped,delivered and installed on-site.
Reply:You are going to want at least 200 amp class mig with a spoolgun to mig 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 ReaganYes,thanks... from what I've read, it seems the mfgr's push the limit of what their machines can do so I've got a 250amp with spoolgun due next week.