Arc or Mig?

[oakeedokee]

I've decided it's about time to learn how to weld, so the question is should I buy a relatively cheap arc welder now, or wait and save up for a relatively expensive mig welder? I know you can weld thicker steel with an arc welder, but how does the quality of the weld compare or is that all down to operater skill?

[unknownmanxman]

I use both.. and i find mig is so so so so much easier to use! You can buy cheap migs from B&Q or sealey...

You can weld thick steel with migs.

A few things to think about... the lance on a mig isnt big and unweildy like an arc lance with a rod on it. I find Migs are just a tidier set up and will use one whenever i can..

However, i do use arc because you can get light portable ones, which u can carry on our shoulder (like a handbag  :P ) and these are very useful.

I think there is an art to getting good welds with arc... but there isnt really with mig,  cos its so easy!


If i was you, i would go for MIG

[Damonski]

Id have to agree MIG is easier.

[seph234]

yes mig is a lot easier :D

[Sharpshooter]

Welding is part of my trade, and can i say they both have their advantages, and disadvantages.

With mig, it takes a long time to learn to do it well enough that you dont need to grind half of it away when you are done. Also, it is easier to weld at awkward angles, such as upside down. It is a strong as arc, assuming you have the penetration. Bad points are, the metal has to be very, and i mean very clean to get a good weld. Also, if you want it to be any good, you really need a gas one. So you have to get a gas cylinder, and keep that too.

Arc is easier to learn, if you want to weld clean bits of plate in a vice on your bench. Once you delve into welding upside down, and then uphill, youll start to have probs. Youll spend lots of time grinding, and wire brushing. On the plus side, once you have learnt the basics you dont have to have have the metal spotless, as it will burn the crud away. You just need to learn how to set the amps, to the rod you use, and the metal your welding.

 All in all, i use tig and arc more at work, but through preference at home, i would use Mig. :D

[wheels244]

Mig - all the way ! Especially if you're welding cars.
Don't bother with the cheap toytown ones - they're rubbish. Buy the best you can afford. The higher the amperage rating the better - not only will it weld thicker steel, it will weld thinner steel, better, because it's not working hard - it's all to do with the 'duty cycle'  -  I won't bore you anymore with the technical bits.
As a bonus - if you change the gas and wire, you can weld stainless and aluminium - but that takes a bit more practice !

[Xtremeteam]

& if yer really tight u can use a CO2 bottle as a mig bottle  

[nzrover]

& if yer really tight u can use a CO2 bottle as a mig bottle  

You can, but at the expense of about 40% of the penetration for any given welding voltage, and you get a resultingly bigger (and uglier) weld bead.

[nzrover]

I think there is an art to getting good welds with arc... but there isnt really with mig,  cos its so easy!

There's a lot less of an art to getting a tidy weld with a MIG, but getting a strong weld with a MIG requires a fair bit of practise, and a lot of preparation to ensure the steel is extremely clean before you weld it.  

I've used both arc and MIG extensively at work in the past and have both setups at home as well.  For automotive work I much prefer the MIG, however the consumable cost of MIG welding is significantly higher than for arc.

The cost of getting set up well for either should be similar.  For MIG you will want a machine of at least 180A that is set up for welding with a shielding gas.  For arc your life (and the learning curve) will be much easier if you get a DC inverter welder - one that will deliver 140A should leave you with a sensible duty cycle using 3.2mm rods.

Buy ALL the safety gear, preferably including a decent automatic helmet - there's nowt like burns or a dose of arc eye to put you off wanting to persevere with learning to weld.

[MuddyMachine]

I use Mig Tig and Arc at work. I would say mig is easier to get the basics, but I tend to use arc more. My Mig kit is to big to move large distences, all though you can get man potable mig kits now, wouldnt think they were cheap though.

As wheels said if you can buy the best you can afford and dont forget the saftey kit. lots of helmets on eblag.

[oakeedokee]

Thanks for the pointers folks. It's going to take a while to save for a decent Mig welder so I reckon I'll get an arc for learning on and making things up in a vice and then get a mig when I can afford it.

[Dave]

I have both and carn't weld, i can stick two bits of metal together but that's far from welding proper. I used the arc first and still find it easier than mig but on small jobs its very hard not to burn right though. thats were the mig comes in, it slower and more controlled.
 That was my finding.  Ps ive got a good grinder  

[Lee_D]

I have a gasless mig , a clarke one. It's welds aren't as neat as those from a gas one but it's plenty sufficient for my needs, It's a Landrover not a Rolls royce at the end of the day.

I also use a Arc mainly for chassis or heavy meatal work such as engine and gearbox mounts which I find a need to create now and then.. :)

By and far though, my favorite item is my plasma cutter  :D  Now that is what I call a toool!


Lee D :P

[nzrover]

I also use a Arc mainly for chassis or heavy meatal work such as engine and gearbox mounts which I find a need to create now and then.. :)

A decent MIG should be well capable of chassis repairs and engine mounts.  I'll weld 8mm plate 8mm with my 210A one and get full penetration.

[Xtremeteam]

& if yer really tight u can use a CO2 bottle as a mig bottle  

You can, but at the expense of about 40% of the penetration for any given welding voltage, and you get a resultingly bigger (and uglier) weld bead.

anywelds ive done you cant tell the difference between CO2 & argo heavy,have to run the mig at a slightly higher current rate to get a neat weld,ill try n get some pics of the welding on the racer ive been doing wityh the mig on CO2

[karloss]

& if yer really tight u can use a CO2 bottle as a mig bottle  

You can, but at the expense of about 40% of the penetration for any given welding voltage, and you get a resultingly bigger (and uglier) weld bead.

anywelds ive done you cant tell the difference between CO2 & argo heavy,

The gas used in an (incorrectly named mostly :roll:  ) MIG welder is there purely as a shield to prevent the oxidation of the weld pool whilst at it's most vunerable (above red heat). It has nothing whatso-ever to do with the ammount of penetration. Slight variations in weld quality will be noticeable but this is down to oxidation levels and "impurities" in the gas reacting with weld matter.
I've used welders of one sort and another for the better part of twenty years now. For welding for the sake of welding it has to be gas every time. But only because I like looking at it afterwards :lol: . At home I have an old SIP 130 amp MIG (actually MAG) This is more than adequate for anything on a Land Rover including chassis work. I use CO2 bottles as they are cheap and give a perfectly good result. I also have an old 200 amp ARC for heavier stuff, also keep a stock of odd ball rods for it, stainless, mixed, and gouging etc. You never know when they are going to come in handy.

[nzrover]

The gas used in an (incorrectly named mostly :roll:  ) MIG welder is there purely as a shield to prevent the oxidation of the weld pool whilst at it's most vunerable (above red heat). It has nothing whatso-ever to do with the ammount of penetration.

CO2 won't do spray-transfer welding, which is the most efficient and best penetrating type of MIG welding.  Therefore the gas used has everything to do with penetration.

[Daz800]

Gas
Gas on a mig welder is just used as a "shield" to prevent  oxidation of the weld. For car work then a co2 bottle is good enough but for more critical work you should go for a argon or argon/co2 mix.

I weld where i work (even if its only if someone off now) and have done so for the good part of 20 years.

What will you need then, well its depends how much your going to do.

Mig wlder with at least 180 amps and if you can go for a "none live" tourch. One that will accept up to .8mm wire and better still if it will take a 5kg wheel spool.

Good and i mean the best you can buy mask (i use a auto dimming /air feed and mine cost the good part of 300 notes.(your never forget your first dose of arc eye :(bloodshot): Any one who welds for a living will tell you this

I am very lucky as i can use any of the welding machines where i work for my own use.We have at work Mig/tig  ali or steel setups, we keep various machines just on ali setups and best of all i can use our plamsa cutter :D  :D

At home i have a mig machine that i can change from a mig to a tig at a change of the lance but for your needs i would just go with whats above.

One last thing you will need is a gas reg for the bottle you will be using.. make sure you get the correct one and when you start to play with it dont turn it full on as you will be waisting gas. Turn up the gas to about 10 ltrs a min.

Darryl

[Daz800]

One thing ive left out is ear plugs..why

If welding under your vehicle they a good send........they stop spatter entering your lugg holes ...... been there/done it :lol:

[denviks]

i have an opininon but its not a completly educated  one.  :oops: i bought my discovery about 8 months ago now. she had no mot or tax on her when i bought it.i knew i would have to teach myself to weld as she needed a new rear cross member , a new rear floor , sills patched and floor areas patched aswell. oh and both front inner wings needed doing inc battery tray  :D

i borrowed my dads arc set and played with it welding bits together in i a vise. no problems. it wasnt the best looking weld but you could beat it with the hammer and it would stay together. when i tried to put it into practice on the disco ....well lets just say it ended up with alot more holes.  :oops:  :oops:

so out with the mig. i did the same by doing a few test pieces in the vise and beat them with the hammer again. they seemed just as strong. after about an hour working on the disco my welds started to look better. i think i was starteing to get the hang of it. 8)  for the next month ( when i had time ) i was out welding my disco up. any bits that were a little lumpy i ground down so it looked tidy.
i must say for a beginer i did find the mig alot easier  to use and i got better results,.i now have no fear when it comes to putting a patch or a new rear crossmember in to my disco.

i would definatly say mig is better for working on landies.  

[karloss]

CO2 won't do spray-transfer welding, which is the most efficient and best penetrating type of MIG welding.  Therefore the gas used has everything to do with penetration.

Spray transfer? On a car body/chassis? I think not.

[pumba]

if a mig set isnt set up properly, wire speed, amps, volts penetration can become a problem, cold lapping etc,

gas, argo shield light is what we use in work all day long bottle after bottle, mig is a lot easier to use in the over head position,, eisier to miantain the right angles, perfect for welding vehicles,

for exsausts, thin plate, etc, tig has got to be the choice,

mma is good for most things, but i would use mig for vehicles, its quite a cold weld, not as much distortion compared with mma,

i gas welded my pick up because i cant afford a mig welder, now thats a pain to do, poping, blowing all kinds of crap back in your face

[landyman Ash]

& if yer really tight u can use a CO2 bottle as a mig bottle  

Exactly what I do and it works a treat for the landy

My local pub fills it for £15 and it lasts ages!!

Defo MIG, got both, ARC so much harder :x

[nzrover]

Spray transfer? On a car body/chassis? I think not.

No problem on a chassis, and essential if you start welding up engine mounts, towbars and recovery points.

[Xtremeteam]

ive just welded my front recovery point onto the racer which is 6 inch by 1/4 plate using a 180a mig running CO2,if ash gets my pic could you post it up for us old chap??

[Eeyore]

The gas used in an (incorrectly named mostly :roll:  ) MIG welder is there purely as a shield to prevent the oxidation of the weld pool whilst at it's most vunerable (above red heat). It has nothing whatso-ever to do with the ammount of penetration.

Hmm, a sweeping statement that I'm gonna have to disagree with I'm afraid. :-k  Gas not only sheilds the weld (on any arc based process, save electrodeless ionic) but can determine the shape of the weld pool and consequently, the depth of penetration for a given set of parameters. Try running a gas mix containing hydrogen and see how it goes! Now, of course, as a welder it might not have sufficient impact on your process needs to worry about, (and many aren't, but in aerospace and other similar apps using freaky materials, it's kinda vital) but its affects can be significant.  

To answer the question, my view is to go for MIG as its a far more adaptable process. I found it easier to pick up, too. Unless you spend oodles of cash though (I mean thousands), welding of strutural aluminium will be a no no, I'm afraid. I've yet to see decent ali welding from an unpulsed arc source (MIG, TIG, Plasma, CMT). TIG is far more afordable for good ali joints. And also very good for steel. And easy to learn, but that doesn't answer your question!

As has already been said, just make sure your weld zones are free from contaminents (oils, underseal, rust, scale etc) otherwise your weld will look like a bird poo / swiss cheese hybrid - which isn't good!

The one thing I would suggest, is to try your local tech colleges for short welding courses - many operate them. Could be a good source of leanring and experience.

cheers
 8)
Eeyore

[Ja1983]

i have a lil old arc welder, tis of the "sip" DIY variety, and while it took me a while to get the nack, i find its fine unless your welding thin stuff,

hopefully the big fat guy who brings pressies will be leaving a gasless Mig for me this year, so will give it a bash, and if all goes well i`ll be re-building the pickup! :lol:

[karloss]

  Gas not only sheilds the weld (on any arc based process, save electrodeless ionic) but can determine the shape of the weld pool and consequently, the depth of penetration  but in aerospace and other similar apps using freaky materials, it's kinda vital) but its affects can be significant.  

Areospace? Freaky materials? Whooa dude. We were talking about welding a rusty old land rover!!
As for the weld pool, that's going to be affected far more greatly (here's an egg grandma) by the arc length and work/stroke angle. And even more so by the ability of the person welding to not flinch at red hot bits of the aforementioned rusty landy falling down his/her back!!! :lol:
 On automated processes, yes, gas is an important, nay vital consideration. On your back, on the drive, under the land rover, using a welder you bought from the local diy supplier, I stand by my original sweeping statement. It aint gonna matter a jot wether you use a mix or a pub bottle. (but then you already knew that )

[karloss]

Spray transfer? On a car body/chassis? I think not.

No problem on a chassis, and essential if you start welding up engine mounts, towbars and recovery points.

You need 250 amps minimum for spray transfer.

[Hangover]

Buy a mig and if you can use it great,if you can't use it give it to somebody who can and let them do it.