MiG welder: how thick can it weld?

[sevilla]

Hi, I never welded but I'm thinking to give it a try. The point is that I know nothing more that what I could find in the pages of the various manufacturer of welding machines. I will use the welder on tractor related equipment and therefore on 1/2 inch of iron or more.
I was initially considering a stick welder now I'm thinking of a MIG welder. My question is: a MIG welder rated for 1/8 or 3/16 thick iron will weld a thicker iron? Will eventually the weld be good? I'm not so much interested in speed of welding since it will be more of a hobby.
Also, which are the difference between a Miller and an equivalent Hobart (I believe they manufactured by the same company).
thank you very much.

 

[orezok]

The rule of thumb for MIG welders utilizing single pass is 1 amp per .001 in of thickness or 250 amps for 1/4 inch. Of course you can make as many passes as you want (using the right wire).

Many people will say that they weld 1/2" all day long with 180 amps, but the penetration is not there.

For 1/2" I would recommend a stick welder.

By the way, a MiG is a Russian fighter which probably doesn't make good welds.

 

[kennyd]

I hate welding threads...they almost always take a turn for the worst-but here is my short answers:

My question is: a MIG welder rated for 1/8 or 3/16 thick iron will weld a thicker iron? Will eventually the weld be good?

No. To weld 1/2" material properly you need a 220 volt machine.

Also, which are the difference between a Miller and an equivalent Hobart (I believe they manufactured by the same company).

The Miller is more "commercial" or "industrial", with a liitle better specs, higher duty cycle, and metal drive components. The Hobarts are great machines for a hobbyist, but have plastic drive components, less duty cycle, and often less adjustability.

 

[oughtsix]

I have a Lincoln 180 220v MIG. I can usually get two pieces of 1/2" to hold together if I chamfer the edges of the pieces being welded and fill in the trench.

I can also make welds on 1/8" that are so lousy they will fall apart just looking at them. Prep and technique have a lot to do with the weld quality.

For me the Lincoln 180 is a perfect size and I have seldom felt limited. I get much better results than with a stick... mainly because I don't spend all day every day with a stinger in my hand. (I think MIG is great for hobbyists) A 120v rosin core wire feed usually gets frustrating very quickly for a newb.

 

[Diamondpilot]

What I did and feel is a great setup for us tractor guys is get 2 welders. I got a Hobart 187 MIG and use it 99% of the time. I weld 1/4" with great results using .030 wire. I do not care for .024 wire after trying it. I got in on sale at TSC with a cart, helmet, gloves, hammer, ect for $525 with a coupon I had 3 years ago.

I also picked up a used Miller 250 Stick Welder. Its a oldie but a goodie and came with 50' leads and about 10# of rods for $100 cash. I have only used it a few times but has came in very handy.

Chris

 

[bobodu]

Spend $60 and get a used Lincoln tombstone....

 

[Jeepnford]

If you can take a welding course first. I know a lot of people are self taught but it helps to do a little of each type of welding before you buy a machine.
Personally I have a Miller 251 and I love that machine.

 

[LD1]

The thickness rating you talk about 1/8 or 3/16, usually refers to single pass.

All you got to do is chamfer and make multiple passes. Even a "average home" stick welder cannot weld 1/2-3/4" in a single pass and get penetration all the way through.

If you are just hobby welding and nothing structural, the mig will be just fine. But I agree, stay away from the 110v and the flux-core stuff. Get a good 220v welder 180-250amps, will do just fine for most home welders.

 

[mbohuntr]

A quick answer... MIG uses a small (compared to stick) wire. Unless you get a commercial unit, they aren't designed to weld heavy stuff. In order to properly fuse metal, the metal must be heated to the melting point. Metal is also a good conductor of heat and the thicker the metal, the more current needed to keep it at that point. Hence, MIG will weld cold on thick stuff, and will not penetrate. Get a Tombstone welder, and a couple of classes. ( The decimal equivilent of 1/8" rod is .125, This is your starting current...125 amps)

 

[ModMech]

When it comes to MIG welders, there are three "classes" of machines, I will get some discussion on the limits, but in *general* ....

1) 120 & 220V "compact" welders sold mostly at discount stores.
- Used for welding sheet metal to about 3/16"
- Mostly used with "Flux Core" wire
- Some can be used with shielding gas (true MIG)
- Have nameplate ratings at 80% "duty cycle" or more of 190A or less.
- NOT suited for welding anything over 1/4" or "big projects", sure they can be made to work.
- Steel only on smaller units, AL ability on advanced units.
- $350 to $1000

2) 220V "Mid-range" MIG welders from the LWS (some carried at discount type stores)
- Used mostly for 1/8" thru 1/4" material (single pass) and up to 5/8" with multiple passes (larger units).
- MIG as-built, but can be converted to flux
- Nameplate ratings at 60% duty cycle of at least 180A (200A-250A typical)
- Suitable for light to medium production welding of material 1/2" and thinner.
- Steel only on the entry-level units unless a "spool gun" is used, more advanced units can weld steel and Al easily with a spook gun.
- $850 to $3500

3) 220v+ "3 phase" welders
- Used on metals from 16ga to 1"
- MIG only
- Nameplate ratings at 20% - 30% duty cycle of 250A and greater (to ~400A)
- Suitable for industrial applications and robotic welding.
- Will weld almost anything weldable with the MIG process
- $2500 to $10,000 and more.

I own and use a Miller brand MillerMatic 251 in MIG mode with mixed gas and 0.035" wire. I CANNOT make good quality welds on 1/16" steel, it warps too much because the minimum current is too high. I will make BEAUTIFUL welds on 3/16" to 5/16" steel with nearly 100% penitration and no beveling. Whatever you weld togather will STAY togather.

I looked for a long time at welders and really wanted to stay under $1000 for everything. In the end, I could not justify spending even $650 on some small welder that would not make quality welds with good voltage controls. I spent about $1400 in total for everything I needed on a good used MM 251 and am GLAD I got the larger unit!

There IS a noticable difference in the weld quality and arc quality of the larger "full frame" machines over the compact units.

 

[captin_insano]

The smaller 220 volt machines are good for hobby work. you can make a good 110 work but you'll be wishing you spent the couple extra bucks so just do it. Now how thick they weld can depend on what shielding gas you use. Theres all kinds of shielding gas. For the hobby guy you cant go wrong with co2. Its cheap and lasts a long time. It also burns in better than the other common gases. The drawback is that co2 will cause more splatter. I have a variety of gases, co2, trimix and argon. I use the argon for aluminum and co2 for most of the steel work. I'll use trimix on occasion when welding sheet metal. I use flux core on all cast steels and for the heaviest jobs, like welding spider gears or suspension brackets onto thick axle tubes. Flux core will burn in the deepest and once you get the feel for it it works pretty good.

 

[CWL]

If you're willing to spend the coin there are several MIG welders on the market that will weld 1/2 steel and are still 220V single phase. I have a Thermal Arc 250amp machine that is rated for 1/16 wire and 5/8 steel. It will spray transfer .035 wire with 75/25 mixed gas. It's a great machine, but it was not cheap. It mostly depends on how much you will use it and how much time you want to spend welding. A good MIG machine will save you a lot of time over a stick welder if you are working on new material. The weld speed is much faster and very litte clean up with gas shielded solid wire. Another great advantage of the MIG welder is when you're tacking up an assembly. Super easy to hold something in place with one hand and tack weld it with the other.

 

[radioman]

I see what you mean kennyD about welding threads.

I am not a welder, but have a hobbyist hobart wire feed model to do what I need to do. After welding for over a year, I relized with the thicker stuff, there is no penetrentation with thick stuff. The only way to "cheat" is to grind the metal edges to have a DEEEEP bevel and then weld in the thinner edge and then put side welds and build up untill its all filled in. This works for me for what I got, but its soooo time comsuming. I probably will need to get a tombstone stick if I gonna continue to do thick stuff for the tractor.:ashamed:

 

[topofthehil]

to clarify flux core with non-welding hobbyists, there are two different types; Self Shielded FCAW (uses no external shielding gas and runs on DCEN polarity. usually used with the less expensive 110 V machines that does not have a gas solenoid) and Gas Shielded FCAW (runs on DCEP polarity and usually uses CO2 or 75/25 shielding gas). when you say that flux core wire does not have the penetration and is limited to thinner metal welding is true with Self Shielded FCAW of the AWS classification E71T-GS, which has a 70K tensile strength, can be used in all positions, but is limited to General Single pass welding of mild steel. it's hard to beat Gas Shielded FCAW for penetration in all thickness & speed of welding in all positions.
you're right, MIG is a Jet fighter, solid wire welding is called GMAW "gas metal arc welding" the old term MIG stands for "metal inert gas".
I agree that one should get the larger welder. if you think you can get by with a 180 amp welder, get a 250 amp. I have six different welders in my shop; one set up for TIG, one for SMAW, one for GMAW, one for Self Shielded FCAW, one for Gas Shielded FCAW and a mobile unit that can do all of the processes listed above.

 

[ampa]

My next project is to build a trailer to trailer my ISEKI G-174.....My new Lincoln 125 amp 20% duty cycle 110 /120 volt is my new toy and has no gas option....or should I say if I buy the gas valves etc....I think this unit is A/C input and DC output....my only question would be...."What" speed...(like dial setting) ....or would trial and error....or just plain practice be the answer I'm lookin' for....I'm usin' 0.35 wire that came supplied with the unit...I owned a gas/flux mig welder unit about 2 years ago that was made in Italy....I didn't care for it at all....so I returned it and bought a O/A Harris copy(China Made) this set sort off blew up(caught fire) my fault for not checkin' the tip as it mentioned to just finger tighten the tips....Hmmmm....so much for that idea.....so I went with the Victor copy so far so good.....first thing I check now is the tip for tightness before turning on the tank valves....anyhow I'm all ears on this mig welding subject....my first welding job a couple days ago....I welded the wire to the brass tip....that sucker is welded better than the metal I was weldin'.... yes and alot of splatter...that is also tough to remove....so I'm confident this little portable will weld what I need to weld....just need practice....and a little knowledge....yes I bought the auto darkening helmet....Thanks guys.....Ampa :thumbsup:

 

[AHNC]

I have a miller 135 110v mig that I like a lot but at only 10% duty cycle, unless I'm only tacking up some work, it gets to be problematic. Duty cycle, btw, is how many minutes per hr you can safely weld. So 10% is 6 min per hr. I'd spend the dough and get a good 220 machine. Also, get a good autodimming helmet. It will make life much easier for you. I'm going to either the 211 or 252 Miller to get a superior machine. Spend some time at millerwelds.com Their instructional videos are excellent. I wouldn't worry about welding 1/2" in one pass necessarily. In a previous life I made a living as a welder. It is not uncommon to just layer one course on top of another to fill a weld and be able to control the heat, penetration, and general quality/appearance.

I have a Syncrowave 180 for Stick and tig which I intend to turn into a mig welder via sale/purchase. The 180 is a nice machine but my eyes and lack of practice have made tig about unbearable for me now. There was a time I could make any welding test anywhere and I was a hand with tig...but you don't just walk up to it and do quality work...so mig is where it is at for me today. Practice, practice, practice!

 

[captin_insano]

I use the flux core, self shielding stuff for thicker metals and cast steels. It will penetrate better than a gas shielded wire with my machine. I use a 220lincoln sp175 plus. Its been good to me, does everything I ask of it as a hobby builder. I even had it fall out of my vehicle going down the highway once. A friend didnt close the trailgate tight, it got banged up but still works like new. Its been a very good purchase.

 

[sevilla]

Thanks for the replies. I do not see a major use for the welder so I'm leaning toward a stick AC/DC 220. Gas and other stuff might complicate my life.

 

[topofthehil]

Ampa... your "tip to work" distance (stick out) should be around 3/8".
if you melted the wire to the tip, then you must have touched the tip to the metal you are trying to weld.
remember that the Cu tip is going to be hot (live) when you pull the trigger. try this; have the wire sticking out of the tip around 3/8 to 1/2", touch the wire to the metal, then pull the trigger.
I wouldn't be welding a trailer until you are a little more experienced.
also, if the wire you are using says AWS class E71T-GS on it, it's mostly intended for static loading and sheet metal work I.E. hand rails, fenders, hobby crafts and such.
it is not intended for dynamic loading, as it has no requirements for impacts... especially at low temps.
thus, you can use it on some parts of a trailer, but not all.
you may want to save up for a AC/DC stick machine so you can cover most situations. you'll need 220 V supply though.
good luck.

 

[Transit]

to clarify flux core with non-welding hobbyists, there are two different types; Self Shielded FCAW (uses no external shielding gas and runs on DCEN polarity. usually used with the less expensive 110 V machines that does not have a gas solenoid) and Gas Shielded FCAW (runs on DCEP polarity and usually uses CO2 or 75/25 shielding gas). when you say that flux core wire does not have the penetration and is limited to thinner metal welding is true with Self Shielded FCAW of the AWS classification E71T-GS, which has a 70K tensile strength, can be used in all positions, but is limited to General Single pass welding of mild steel. it's hard to beat Gas Shielded FCAW for penetration in all thickness & speed of welding in all positions.
you're right, MIG is a Jet fighter, solid wire welding is called GMAW "gas metal arc welding" the old term MIG stands for "metal inert gas".
I agree that one should get the larger welder. if you think you can get by with a 180 amp welder, get a 250 amp. I have six different welders in my shop; one set up for TIG, one for SMAW, one for GMAW, one for Self Shielded FCAW, one for Gas Shielded FCAW and a mobile unit that can do all of the processes listed above.

There is also E71T-11, multi pass that you can use to fill a deep V notch.
BTW, self shield flux core runs hotter than the same size solid wire. The flux core wire is formed into a tube and will there fore run hotter. Most hobby mig units will max out at 20-20 volts which are good enough for solid and self shielded wire and short circuit transfer. For gas shielded flux core wire, you need 23-37 volts, spray arc transfer and that is outside what a hobby welder can do.

This is what proper fusion looks like.