Info about mig welder

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  • Dunc
    Senior Member
    • Jan 2003
    • 624

    Info about mig welder

    Neighbor (the mini lathe guy from earlier posts) introduced me to one of his buddies who has a few tools for sale - he's upgrading. Anyway...

    He is selling a mig welder. Specs include "everything but the bottle." Unit runs on 120 volts, 20 amps; max output is 70 amps. Accepts flux-core or plain wire. At least to start, I would use the flux core.

    When I used a 220 volt/225 amp stick welder I recall that the home welders available (non-mig) of ~50 amps output were not very capable.

    Now, I don't want to build a ship; are these "mini" migs significantly better than 70 amps would suggest? Can they weld thicker stock using repeated passes? What would be their maximum practical capacity? Don't mind a bit of prep (bevelling... or ?) but I sure do like the small size/weight. The 120 volt is a plus. Yes, if pushed I could install a 220, 50 amp circuit but I would rather not.And the price can't be beat (compared to the same model new).

    Your thoughts please. Thanks
    Dunc
  • lane
    Senior Member
    • Aug 2005
    • 2691

    #2
    They are fine for thin stuff . 1/4 thick is about max. I had a 100 amp up graded to a 180 which is a lot better . The little migs are more or less for sheet metal .
    Every Mans Work Is A Portrait of Him Self
    http://sites.google.com/site/machinistsite/TWO-BUDDIES
    http://s178.photobucket.com/user/lan...?sort=3&page=1

    Comment

    • C - ROSS
      Senior Member
      • Nov 2004
      • 288

      #3
      Had one of the 120V units given to me several years ago guy that had it didn't like it, guess what nither did I.

      Just wasn't enough welder. Gave it away to another sucker. Now have a Hobart 175, it is almost adiquite for medium work. Can't complain about it too much as it does what i ask of it.

      I sure wouldn't spend any money on one of the 120V units, save and buy a larger rig.

      Ross
      GUNS Don't kill people
      Drivers using cell phones do.

      Comment

      • Rookie machinist
        Senior Member
        • Jul 2007
        • 302

        #4
        Spend the money to get a 220v welder. Most of the 110v units have poor duty cycles and low capacitys. Just my 2 cents.

        Comment

        • Fasttrack
          Senior Member
          • Jul 2005
          • 6300

          #5
          Frankly when it comes to mig welders, don't buy 110 volt units. This is, of course, just my opinion, but i think it well founded

          I own a 110 volt 30 amp stick welder. It has an 80% duty cycle at 90 amps and is capable of 140 amps. I keep it turned up at 140 amps just about all the time and run 1/8" MAX - usually 3/32. This welder will easily weld 1/4" but at 3/8" and larger it neccessitates bevels and sometimes multiple welds.

          You will find that SMAW or stick welds handle fatigue cylces better than other methods of welding and offer better penetration in many cases. MIG is great for thin material, but when you start getting bigger than 1/8", 70amps won't take you too far at all. Most MIG units have the heat controlled by voltage rather than current - meaning that the dial you use to adjust the heat is marked in voltages rather than amperage like a stick unit. That 70 amps is the max output and should correspond to something like 31 open circuit voltage. My welder has a max open circuit voltage of only about 25 volts, but it is capable of sourcing 130 amps at that setting, which is suitable for most small jobs.

          As far as multi-pass welding goes, you bevel the pieces to be welded - usually beveled on front and back of both pieces. Then you lay down a root pass where the material has been ground thin. Then you just work your way up laying down beads on either side of your root pass. There are many text books out there that will show you the order to put them down in and give you a good visual of what it looks like.

          If it were me, i'd consider buying a stick for 110v if i could get it cheap. For MIG, i'd hold out for a 220 volt unit. I'm biased towards SMAW, though ...

          <edit> They do make 135 amp 110volt MIG units, and they handle 1/4" about as well as my stick does. With an 1/8" electrode, i can burn a weld in 1/4 plate in one pass. Not sure I could do that with a MIG since you'd probably be running smaller wire size anyway, but as far as a 70 amp welder goes, i would suspect that the max practical size would be something like 1/8"

          You can do 1/4" by making a pass front and back, but it won't take you long to realize that there are many jobs that you just can't get in there to weld either side or even bevel them so a bigger welder is nice. Also, if you have to weld aluminum, you need lots and lots of heat. On the otherhand, if you can get this unit cheap, its a good place to start until you can get 220v lines and a bigger welder.
          Last edited by Fasttrack; 04-01-2008, 11:13 PM.

          Comment

          • ahidley
            Senior Member
            • Feb 2005
            • 1676

            #6
            If you dont want it , I sure do....

            Comment

            • snowman
              Senior Member
              • Mar 2004
              • 2057

              #7
              It's all about what you are going to be using it for.

              When you upgrade to 220, you are going to wonder why you didn't do it earlier...but any welder is better than no welder.

              People complain about the 110 welders, but they'll do the job if you do the prep work.

              Comment

              • snowman
                Senior Member
                • Mar 2004
                • 2057

                #8
                And let me add this...I upgraded, but my 110 is still in the garage, and gets used plenty. Nothing better to loan out to someone when they have a welding project, or take up north when I need to do some patchwork on the woodstove or something. It's mobile!

                Comment

                • davidh
                  Senior Member
                  • Dec 2007
                  • 1265

                  #9
                  i have a mig 130 that mac tool and astro sells. (i use to be an astro distributor) it works very well for maybe up to 3/16 . its also non-flux type wire so you need a 75/25 gas bottle with it. i think for the smaller things i do its a great investment. about $400 new now, and i have had mine for nearly 20 years. they still selll this unit so it must be pretty decent. made in italy. the same company had a mig 110. they do not offer it anymore so that tells me something right there. too small. both of these units run on a 30 amp house circuit and i would highly recommend the mig 130 to anyone. anythinig less than 130 amps is not, in my humble opinion, a very good investment.

                  i also have a miller 180amp wire feed that i have had for about 6 years with a aluminum spoool gun option and its a fantastic machine. now its been upgraded in the new model to a 220 amp machine and they sell for aobut $1500.

                  i am NOT a welder but have done lots of welding with great results. auotbody, special tools, workbenches, general maintenence, exhaust stuff, etc. it takes a real guy to weld with stick. even i can weld with wire. . .

                  davidh (the old guy)

                  Comment

                  • bruto
                    Senior Member
                    • Mar 2008
                    • 739

                    #10
                    I've had a couple of good quality 110volt mig welders, and while I'm sure 220 would be better for many things, I've found them quite adequate for many jobs, and very convenient. I've heard a lot of bad things about the cheap ones the places like Harbor Freight sell, especially if they lack fine settings.

                    My first MIG, a Hobart 95, paid for itself in about the first hour of use. I bought it to rebuild a wrecked car that needed a new roof welded on. It did the job well, and I drove the car for years. I later gave the Hobart to my son, and bought a new Miller 135. The Hobart was good, but the Miller is better. For whatever reason, the adjustments are just right, it's easy to set, and it will strike a useable arc at lower settings than the Hobart could. It does just what you need with very little fuss. You can weld a tin can with it. Of course it's also not a cheap machine, but there seems to be a reason why Milllers cost a little more.

                    I have a 220 stick welder for the big nasty stuff, but it's really nice also to have a welder you can run anywhere off an extension cord. If it's to be your only welder, a 110 may not be the best bet, especially a 75, but small welders still have their place.

                    Comment

                    • vdisney
                      Junior Member
                      • Apr 2006
                      • 14

                      #11
                      I'm with Snowman. I have three welders in my garage. 110v mig, 220v set up for spool and a 220v mig. Migs like to run hard. My 220v 210amp doe not like to run at 40amps on thin material, but the 110v luvs to run full out on the same material. Buy the 110v, later you will end up with a 220v and end up using them both. Respect, Verne

                      Comment

                      • kendall
                        Senior Member
                        • Sep 2006
                        • 2501

                        #12
                        agree with Vern, I have a 220v mig, and it works great for a lot of things, but when I have to weld thinner material I end up having my friend do it on his little 110v.

                        there is some overlap where they both work about the same on certain thicknesses though.

                        Mine will do the thin stuff, but not as neatly as it does the thicker material.

                        Ken.

                        Comment

                        • Fasttrack
                          Senior Member
                          • Jul 2005
                          • 6300

                          #13
                          Ummm ... a big welder will do small stuff just as well as a little welder if you set it up correctly. To weld thin material with a big MIG, you just need to change wire sizes. Then it will perform the same (actually usually better because they have a more consistent output) as smaller units. They usually have a high voltage start feature that allows you to start an arc at low current/voltage settings easier than you can with lower end models.

                          I think most people end up stitching with big MIGs and have not as "pretty" beads when welding on thin material because they are too lazy to change to a smaller a wire size. I know because i'm one of those who is too lazy But my point is, if you've only got money for one welder, make it a big one. If you can find room and money to keep a few around, then by all means keep a small one set up for small stuff and a big one set up for big stuff!

                          But 70 amps is really small... buy it if you can get it cheap but i think you'll out grow it quickly. A 140 amp - or 135, whatever - is a good size for your average home shop stuff.

                          Bruto - A stick welder for the big nasty stuff I personally find stick to be much easier than MIG. I think it offers you more control, visibility, and penetration than similiar MIGs. I've got a friend who is a TIG welder at a machine and die place and he's always surprised that i can make welds that look the same if not better than his TIG beads with a stick. TIG is nice too, especially for small stuff since it offers such good control, but for heavy stuff, it takes more time than a stick, requires lots of surface prep and in many cases should be peened or stress relieved in some way since it cools faster than beads layed by stick welders. I think stick welders are under-estimated these days. For me, at least, i found that they were easier to learn, it sort of comes natural for me. MIG makes me feel like a robot ... pull trigger and go ... where's the fun in that?

                          But like i said - i'm biased!

                          Comment

                          • MickeyD
                            Senior Member
                            • Jun 2004
                            • 934

                            #14
                            Unless there is no way to get 220V in your shop, get a 220 welder. I learned how to mig on a big 3ph miller about 25 years ago, and coming from stick it was so nice. A few years after that I got a little century 110 mig box and I thought that I must have had a head injury and forgotten how to weld. Fought that thing for years until I finally upgraded to a Millermatic 175 and I just love it. I works flawlessly, wire always feeds right, and the welds come out very nice. I have used a friend's Lincoln that was the same size and I was not impressed. The feed mechanism busted about halfway through the job and it took a couple of weeks to get a new one in. There are a lot of things that you can go cheap on, but a wire welder is not really one of them.

                            Comment

                            • macona
                              Senior Member
                              • Aug 2006
                              • 9425

                              #15
                              70 amps? It might be something like a Lincoln Weldpak 100. They are rated around there at a 15-20% duty cycle. Good for sheet metal to about 1/8". Thats about it.

                              If its cheap enough and comes with everything including a regulator it might be worth 200 - 250. Half that if it is not USA made.

                              Dont bother with the flux core if you do get it. Go down to the weld shop and plunk down $60 for a 20cuft bottle of 75/25 and go with that. Flux core in a little machine like this is total crap.

                              Comment

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