What's the minimum welding thickness I should be looking for in a MIG/TIG?

In a bit of a conundrum. I want to start learning how to weld, maybe build some workbenches, then possibly a Locost once I get good enough. My workshop is in an unfinished basement, so the fumes from MIG would be an issue unless I get proper ventilation, or roll the unit outdoors.

Because of this, I thought TIG might be the way to go because of the lack of fumes. Not the natural progression of learning for welding. Oh well. Having never welded before, I'm not sure what capability I should be looking for. I know the 220V units for MIG are highly advised, and those usually go up to 5/16" steel or so. The 110V's will only do up to 3/16". I've seem some Locost builds happen with a 110V, but there's a strong push to go bigger.

TIG seems pretty expensive, and again, I don't know what capability I'm looking for.

You can do almost everything you would ever need to fabricate and automobile from scratch with a 220v TIG rated for 1/4".

Don't worry about natural progressions either - TIG and MIG share very little in technique.

For indoor use in the basement - TIG all the way. In fact, TIG anyway because once I got one... I stopped using the MIG unless I was in a hurry or I was out of argon.

Why not a dual unit that does both?
it's a basic unit, with lift start tig, but it's done everything I needed it to. I got a spool gun that lets me weld (very poorly) aluminum as well.

northern tool multi purpose

MIG will be easier to learn out of the box and much quicker to make the same welds, assuming you are playing with mild steel. It is more forgiving, and helps you get some fundamentals down before moving to TIG. A quality 110V welder like a Lincoln 125+ would be enough to build a locost, there really shouldn't be anything on it thicker than 3/16" anyway. Plus, switch the hardwire out for some flux core and I've used my little Lincoln on 1/4 thick material and it was fine. (Stretched the frame on a Samurai 2', and then jumped it repeatedly with no issues)

To me a TIG is a 2nd or 3rd welder to buy (It was my 3rd) unless you are planning on mostly welding stainless or aluminum, which I don't suggest starting to learn to weld with.

A 110 mig unit will be more than adequete welding up a 14 gauge locost frame, though keep in mind a lot of those 110 weldders advertise the thickness with flux wire, mig doesn't penetrate as well IIRC, they are also picky about where you plug them in, 20 amp outlets and 12 gauge extension cords are more or less mandatory for max performance. I wouldn't be too concerned about mig fumes on mild steel as long as you have a fan out a window nearby.

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Possibly better deal, but I'd have to figure out my outlet situation: http://kansascity.craigslist.org/tls/4289609000.html

I have to agree that a 110V MIG is all you're going to need for 90% of your automotive welding needs. Hell I've welded on 1/4 inch with my 140 AMP MIG and I just make more then one pass. I also have a TIG. And it's also true that once I got that my MIG has seen very little use. Mostly simple repairs to my truck or trailer and most exhaust work unless it's SS. Then I just tack it and remove it to TIG weld it. If I was building roll cages or doing a lot of exhaust work, or body work then the MIG would get more use but I don't build those all that often.

I'm guessing that by "lack of fumes" you are talking about MIG flux welding. Please, anyone else correct me if I'm wrong but I do a fair amount of MIG (non-flux) and TIG and haven't really noticed a difference in the fumes. I've never actually done MIG flux welding.

As far as welder costs go, you can find cheap TIG's just like cheap MIG's. My TIG is an industrial Linde that goes up to 300 amps and I got it for $500, but it weighs 500 lbs. My 110V Hobart MIG cost the same. If you are buying used and can spare the space an older MIG or TIG will be alot cheaper and larger. Any of the big name welders can be serviced pretty must indefinitely from my experience. If you are just starting out, I wouldn't recommend anything other than a MIG. By far the easiest thing to learn on.

I've never been a fan of using 110V MIG welders for anything over 1/4". I don't know what wall thickness the Locost square tubing frames usually use but I wouldn't trust a 110V MIG doing an inner corner weld with anything over a 3/16" wall. I'm sure it can be done but I wouldn't feel comfortable with it as a chassis weld. Someone that has built a Locost could chime in on the ability of a 110V MIG for the chassis work.

Another vote here for starting off with a 110 volt MIG unit. I built my Locost using a 110 volt Hobart 135 (Miller's economy brand) with no issues.

Shameless plug for my Locost build gallery: https://picasaweb.google.com/marktsui1975/MarkSLocost#

A 110V MIG will do 98% of all welding you will ever need. Do get a good brand like Lincoln, Hobart or Miller. I have welded 3/8 with my Lincoln by beveling and making multiple passes.

I do use flux core wire, it spatters but it also gets a lot hotter than solid core with gas.

In reply to ThingWithWheels:

Yeah, flux wire produces some pretty nasty fumes, you definitely want gas and solid wire for indoor work.

chassis/ cage stuff should be done with a tig imho.

I concur with some of the above: if you are using gas, MIG isn't that bad, fume-wise. WRT comparisons between the processes, I'll say this: it's easier to "weld" with MIG, but it's easier to make "good welds" with TIG. You read that right. TIG is slower, and much more controlled. If you have any manual dexterity, you will pick up good technique faster than MIG. MIG, to me, is like pulling the trigger on a tiny flame thrower, once you pull it, something is happening, good or not. And you will have a very difficult time seeing the puddle. Learning TIG made me a much better MIG welder, and I think it is actually much easier in every way than MIG, if you value the quality of your welds.
I purchased an Everlast TIG setup for $850. The MicroTig 185. Excellent in every way so far (3 years in).

I'm building a Locost, and I have not a MIG and TIG. If you've never welded before, and the goal is to actually, someday, drive the Locost, I'd say get a MIG. It'll teach you the basics of controlling the puddle, and limit the number of variables. Learn to control power, wirespeed, and your torch technique. TIG takes longer to learn, and longer to get good at. If you don't plan on welding aluminum, check out the combo units from ThermalArc or HTP. Everlast Generator has an interesting unit, but they're new kids on the block and some question how long they'll be around.

For a MIG unit, a 140amp unit ought to do just fine. Can't go wrong with Miller or Lincoln. Hobart is good, but doesn't have infinitely variable power. I wouldn't be scared of ThermalArc. I've used the Eastwood 140, and it works, but I'm not a big fan of the gun. The trigger is really short and stiff, so it's harder to feel when you're wearing gloves.

I have a Miller 180 MIG, Diversion 180, and a Chicago Electric 110v MIG GMAW (not flux) guy.

carbon wrote: chassis/ cage stuff should be done by a welder who knows what he is doing.

Fixed.

Tweco (ThermalArc) 141i: Multiprocess DC (steel only, unless you use a spool gun for Al) http://store.cyberweld.com/twfa14miwew1.html Note that it does not come with TIG torch or pedal.
Everlast MST200: Comes with what you need for MIG and TIG. DC only.http://www.everlastgenerators.com/PowerUltra-185-311-pd.html
HPT MTS 160: Does not include TIG gun or pedal, DC only. http://www.usaweld.com/MTS-160-MIG-TIG-Stick-Welder-Package-p/60160mts.htm

I, personally, chose a dedicated TIG machine since I already have MIG.
If I had to get another MIG machine, I'd get this: HTP MIG 130. 3 year warranty. http://www.usaweld.com/ProductDetails.asp?ProductCode=60130&CartID=1

TIG is really cut out for delicate work where extremely good heat control is needed, so chromoly tubing, very thin metal, and aluminum. Anything else there are faster, cheaper, easier processes that will give the same results.

Streetwiseguy wrote:

carbon wrote: chassis/ cage stuff should be done by a welder who knows what he is doing.

Fixed.

I guess my assumption was that he would become proficient with whatever welder he was going to fabricate his chassis beforehand. I absolutely concur with the above statement though, if youre planning on welding a chassis for your lowcost project then get to a point where you are making your welds safe or dont do them yourself. Take some classes, get good, then weld it up.

Mig is definitely faster, but I think the beginner will get better welds with TIG- again, it takes some dexterity, but you'll be better for it. MIG is just too easy to get a bead down.... any bead. Mostly bad beads, because you simply have a harder time knowing what is going on down there with the very vigorous spark/gas cloud. With TIG you can hold a puddle forever. E36 M3ter is that it'll take forever to weld a locost frame.

Did anyone read the part about him doing this in an unfinished basement?

Of course you can do 99% of everything you ever need with MIG... including choke your family and burn your house down. If he said "In my garage" or "in my shop" or "in my driveway" or in my "all brick and concrete unfinished basement" or even "just the one time in my straw house but I'll soak it first" I'd agree wholeheartedly (well... not quite... I do still use my TIG for everything I possibly can these days).

TIG makes almost no fume, no flying sparks and does the same or better welding with just a little more time and money up front. It really isn't that hard if you have ever sweated pipe or braised anything. I've done it in my upstairs bathroom to repair a stainless shower railing. It's pretty benign on the danger angle.

In reply to Teh E36 M3:

You can make bird crap welds with any system, with TIG its just slow, expensive, frustrating birdcrap welds. I think your mask is bad or needs the darkness adjusted if you cant see anything running any wire feed welder, including flux core. If you really want to drill in the underlying principles oxy acetylene is the way to learn.

I have both the MIG and the TIG from Lincoln. The learning curve on TIG is huge compared to the MIG. I teach people how to MIG sheetmetal butwelds in about half an hour. So far, only one person has managed to join two pieces of twenty gauge in my garage.

Not mentioned yet is that TIG is unforgiving of any contamination. If it is not pure, unblemished and degreased metal it ain't gonna go well.

If anyone starts to sing you a song about how MIG beads are harder to grind down than TIG, tell then to bring you the rockwell results from the same filler material or go away.

No truth to the fact that TIG warps metal less.

I have seen a backhoe bucket welded with a 110V welder, so its not like they won't do serious work if you plan it well.

I'm using a 110v MIG to build my "locost" in my garage. It's been laying down fine welds. I agree about the sparks though, depends on how flammable your basement is.

The only time I've ever had a problem with fumes when MIG welding is when the steel is contaminated, either oil, paint, E-coat, zinc, etc. I have never welded with a MIG flux-core welder, I take that back, I did and didn't like it.

Giant Purple Snorklewacker wrote: Did anyone read the part about him doing this in an unfinished basement? Of course you can do 99% of everything you ever need with MIG... including choke your family and burn your house down. If he said "In my garage" or "in my shop" or "in my driveway" or in my "all brick and concrete unfinished basement" or even "just the one time in my straw house but I'll soak it first" I'd agree wholeheartedly (well... not quite... I do still use my TIG for everything I possibly can these days). TIG makes almost no fume, no flying sparks and does the same or better welding with just a little more time and money up front. It really isn't that hard if you have ever sweated pipe or braised anything. I've done it in my upstairs bathroom to repair a stainless shower railing. It's pretty benign on the danger angle.

My unfinished basement is all concrete walls and floor. Does that make a difference?

I didn't realize that the fumes were caused by flux welding. I was intending on using gas. However...if I'm using a 110V unit, I can roll it out the door (it's a walk-out basment) and weld there if the weather's good, or at least weld next to the double doors with fans going full blast.

Thoughts on that?