How much to spend on MIG welder for my situation?

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For a few years I've been TIG welding some structural tube, steel, 7/8", 1/16" wall thickness with a reinforcing telescoping 1/16" wall tube on the inside.  I don't do to many, because I don't make a living wage on the end product.  I own one of the small Miller inverters.In the interest of speeding up this so I don't loose money on the project, or wear out the Miller, I'm looking at other solutions.  Originally brazing with oxy-fuel even though I have no experience brazing, or MIG.  Again, practically zero experience other than running a bead in a welding class (where I spent all of my time training on TIG).Lets say I do 400 of these tube welds a year, and make $10K when everything is painted, packaged, sold and shipped.  Not much.I'm looking into the $550 Lincoln MIG welders that supposedly put out 140 amps (or have 140 in model name?).  There are varous models, and I haven't sorted out the diffences yet.  Are these sturdy enough to hold up to 400 of these tube welds per year and still last a couple of years before I start replacing torches, or total failure?  I would imagine there are a few other things I would start doing MIG, but still nothing heavy.  Are these $550 hobby ones worth it or do I need to step up in price?
Reply:situations have a bad habit of changing when you start welding. like i tell people when they ask me the question you are asking. if you want a small capacity welder now you will need a more powerful one later. don't handicap yourself from the start. my advice is buy at least a 180 amp now and unless you go ape like most of us do here it will do 100% of your needs and 80% of your wants for a long time. it's your money though.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:i dont know what the part looks like but can you put time/money into a positioner and/or jig that will allow you clamp the parts into place and weld? busting out finished pieces faster instead of looking at picking up time between parts by switching away from TIG.mig welds will be big & bulky compared to TIG on 7/8" material? can you leave the MIG welds alone after welding or will you have to grind them down? if youve got to grind them down, you just blew any time saved.i think the forum would have to see the part to help devise processes for saving time.
Reply:I would grab one of these ESAB Caddy MIG 160i units while you can still get one for $469. delivered, as long as you have 240v power available.http://www.ebay.com/itm/ESAB-Caddy-M...-/110951766243"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:1/16 wall is relatively thin so if you go with a 110vac machine u are not going to get a whole lot of control over the arc.  a 230Vac machine is always a better choice and the components and duty cycle will be much better.  as your voltage controls bead appearence, you want an infinitely adjustable voltage control over a stepped one or a machine with plenty of taps (I always refer to the ESAB MigMaster 250) for an example which has 24 overlapping voltage settings...The other advice you received is excellent also and pics always help.  A positioner with TIG would probably be just as fast as the mig optionTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:I agree with the guys so far saying that streamlining your setup will gain more time than switching to mig.Pics of the part (at least the welded area) would help.My name's not Jim....
Reply:This morning I bought a used pro bicycle mechanics clamping stand.  Allows me to clamp instantly and rotate the workpiece.  It has rubber jaws which would be a problem if heat were to travel to them, but I think my work piece is large enough where that will not be an issue.I'll look into the suggested models, and appreciate the suggestions on how to keep things near profitable.What I'm trying to do is double the wall thickness by joining the two tubes to make one near the heat affected zone, so it comes out to be 1/8" wall.  The tolerances are very close so it requires boring and facing the (round) tubes, sometimes a wood block and hammer for persuasion.I need better tools for the facing and boring, might be able to do both tasks with one.  In the past I had access to a band saw, so future cuts may be more sloppy and require more cleaning time.  After the suggestions I think a band saw and facing tools might be the best investment.Last edited by kopek; 09-17-2012 at 10:10 PM.
Reply:kopekNo one should recommend a tool or process unless they know what it is for;and you have not made that clear.Please post: prints/photos/explanation, of your condition, and you will get  more complete answers.Another tools without technique is not an improvement.Opusp.s.  Your beat me to introducing a bicycle-vise [as a positioner] to this forum.Provide a hold-down to the floor for cantilever, and retrofit the jaws with brass, aluminum, and steel and you can weld in free space like the hippos in Fantasia
Reply:"Weld in free space like hippos in Fantasia", I'll need to keep that in mind when the vise arrives.  I think the vise will make a difference.Here are more details, this is to make a chair have more height.I make inserts that fit into the original chair legs, the smaller of the two tubes fits in the chair legs and joined with enough heat and a few dabs of filler metal to close up the gap.  These aren't aircraft parts or for use in a nuclear submarine.  The welds don't need to be beautiful, just not more hideous than the completed one in the second photo.I'm glad to have read more about the limited heat settings for MIG welders, I just assumed they were all infinite control, obviously not ready to make an informed purchasing decision yet.Currently thinking the money would be better spent on a bandsaw so I don't need to spend more time cleaning up the cuts. Attached Images
Reply:I'd suggest a saw and a possitioner like everyone else has. Tig will always bee the cleanest weld so you're not going to get anything but uglier than the weld you've got. but saving on prep and clean up times will be where you can do better. I might suggest a cold saw instead of the band saw just to speed up the process. a nice cold saw will leave it as clean as a band saw. and be 20 times quicker.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger