- Thread starter Tino
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a 500 pound inverter will weld nearly as well as a 5000 pound inverter tig or mma wise, of course there will be differences though, but when it comes to migs thats where the differences are massive. i see people on the forum saying they cant weld with there clarkes and other cheap migs and i say to myself well either could i. when you start laying down welds with a big pro machine you will see massive differences. as for weld qaulity mig is top, thats just a engineering fact, as mentioned above tig and mma put so much more heat into the material, in some applications it that not important, in others it is. i learnt to weld in collage mma and only started to mig weld about five years later so i'm not biased. all i ask for is a mig that will weldn as soon as i switch it on and never ever give any trouble what so ever such as birds nest the wire etc, can change the wire role in under a minute, work in the cold of winter and the clam of summer.
I dont think theres anything wrong with mig as a process, or the final quality of the produced weld for all of the already stated reasons.
Im with malcom in that I think the reputation comes from its easy to make a mig weld that looks pretty, but is sat on top of the surface with low penetration, so its not easily apparent to the non expert that its a bad weld.
Bad mma welds tend to have large holes in them with horrible big voids when you chip away the slag so its less easy to get away with one that has to pass a quick visual.
I reach for the arc, then the tig then finally the mig in reserve. But thats mostly because I have a proper 3 phase arc/tig set, and a crappy little cebora mig that usually ends up with me having to fight the feed rollers or holding the torch just so to get it to feed smoothly (must change that liner again)...
Im with malcom in that I think the reputation comes from its easy to make a mig weld that looks pretty, but is sat on top of the surface with low penetration, so its not easily apparent to the non expert that its a bad weld.
Bad mma welds tend to have large holes in them with horrible big voids when you chip away the slag so its less easy to get away with one that has to pass a quick visual.
I reach for the arc, then the tig then finally the mig in reserve. But thats mostly because I have a proper 3 phase arc/tig set, and a crappy little cebora mig that usually ends up with me having to fight the feed rollers or holding the torch just so to get it to feed smoothly (must change that liner again)...
to be honest i think the idea of penetration gets far to much attention on the forum. on most applications full penetration is not warrented, when it is well mma or mig your probably going to have to put a chamfer on the edge. if penetration is vital you will have to chamfer as burning right into the material is going to cause lots of extra problems in itself. mma sticks are dirty things really full of silicon and what not, mig wire is just plain steel mainly. of course there is the issue of penetration mig wise when it comes to hot rolled plate, the weld may not even penetrate the scale, deaths have happened in the uk because of this (a towbar came away from a home made trailer on a busy road and went across the line into an on coming car). many people grind the scale away but if your mig is set up right with a stiff as possible wire you need not grind. this is another example where a heavier mig machine has a firm advantage as 1mm or 1.2 mm wire makes this much easyer but you still have the control when working with thinner material.
English Steve
Senior Bumpkin
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Can't agree about the penetration Danny - if you don't need a full pen weld, you're using too thick a material in the first place. A properly formed full pen weld has the same strength as the parent material, and effectively makes the two parts become one.
As Snowy said, you have to use the process which suits the job in hand - outside on plate over about 5mm and it's stick every time for me. Inside it's mig because it's quicker (for me) and cleaner. Up a ladder - stick, in the cowshed - stick because I can hook it over my shoulder and weld standing in you know what. Thicker plate inside or outside I would use stick, but that's simply because I don't have a suitable mig set for anything much over 10mm with edge prep.
Is mig an inferior process? definately not. We manufacture hookloaders and skip loaders among other things, which are classified as lifting equipment. These are mig welded without exception, and all of our welders are coded to the relevant standards. One of the joints requires a continuous bead which is over 1m long - try doing that with a stick set!
As Snowy said, you have to use the process which suits the job in hand - outside on plate over about 5mm and it's stick every time for me. Inside it's mig because it's quicker (for me) and cleaner. Up a ladder - stick, in the cowshed - stick because I can hook it over my shoulder and weld standing in you know what. Thicker plate inside or outside I would use stick, but that's simply because I don't have a suitable mig set for anything much over 10mm with edge prep.
Is mig an inferior process? definately not. We manufacture hookloaders and skip loaders among other things, which are classified as lifting equipment. These are mig welded without exception, and all of our welders are coded to the relevant standards. One of the joints requires a continuous bead which is over 1m long - try doing that with a stick set!
Welding Mild Steel using MIG is classed as a semi-skilled process. You wont find MIG being used on an Offshore Structure or any highly critical fabrication. It is classed as semi-automatic in that the equipment assists the welder, the so-called self regulating arc.
Recently, within the past 10 years, it has become more acceptable. There are some shipbuilders using MIG and some Pipelines have been welded with Automated MIG.
This has been possible due to advances in equipment design, the MIG wire itself and the shielding gas, however, it is still prone to lack of fusion problems and as such will not be accepted by many Professional Welding Engineers. You would expect far more X-Ray failures with solid wire MIG than you would get with Flux Cored Wire and especially TIG.
With Aluminium MIG the quality of the weld is highly dependent on the cleanliness of the area to be welded. With TIG you can use AC which helps "clean" the weld.
On this forum we are mainly talking car repairs, garden gates etc etc. For these types of applications MIG is perfect
Recently, within the past 10 years, it has become more acceptable. There are some shipbuilders using MIG and some Pipelines have been welded with Automated MIG.
This has been possible due to advances in equipment design, the MIG wire itself and the shielding gas, however, it is still prone to lack of fusion problems and as such will not be accepted by many Professional Welding Engineers. You would expect far more X-Ray failures with solid wire MIG than you would get with Flux Cored Wire and especially TIG.
With Aluminium MIG the quality of the weld is highly dependent on the cleanliness of the area to be welded. With TIG you can use AC which helps "clean" the weld.
On this forum we are mainly talking car repairs, garden gates etc etc. For these types of applications MIG is perfect
mike os
just a little insane.....
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bottom line is inertia.... we have always done it this way so it must be the best/most suitable.... & the assumption is as often as not wrong.
assuming the equipment is up to the job there is no reason for there to be any structural difference between mig & mma, In less than ideal conditions use the tool most suited to the job
as to skill... MMA is a piece of **** to produce decent welds....even I can do it LOL, mig I still cock up occasionally
assuming the equipment is up to the job there is no reason for there to be any structural difference between mig & mma, In less than ideal conditions use the tool most suited to the job
as to skill... MMA is a piece of **** to produce decent welds....even I can do it LOL, mig I still cock up occasionally
pedrobedro
Man at Matalan
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Kemppi have developed a mig system called FastROOT™ which is also useful for thin sheet welding and is being used on pipelines to speed up root pass welding and it is used for spiral heat exchanger production where some of the weld runs are hundreds of metres long, pressure bearing and have to be spatter free. Advances are being made that will see mig being used more and more and becoming more skilled and indispensable now inverter technology is being widely adopted.
NTwoO
More skill with grinder than welder
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I've followed this thread from the start (and also mentioned my opinion). Even though I still don't understand the rant, I've learnt alot. There are some statements that I certainly agree with. Cheap TIGs are far closer to expensive TIGS than what cheap MIGs are to expensive MIGs. Unfortunately most people end up with cheap MIGs. For a decent Alu mig welder you must be prepared to spend moohla.
On the point of the blue shale. That is interesting and explains my ****ty welds on hot rolled steel in the beginning. Not knowing that cleaning would solve this, I went for the stitch function on my welder to flame through the shale and not burn through. It is strange that one does not see the functionality more in the intermediate range MIGs. Spot welding, yes, but not stitch.
On the point of the blue shale. That is interesting and explains my ****ty welds on hot rolled steel in the beginning. Not knowing that cleaning would solve this, I went for the stitch function on my welder to flame through the shale and not burn through. It is strange that one does not see the functionality more in the intermediate range MIGs. Spot welding, yes, but not stitch.
Drains
Yeah, nah.
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One of the joints requires a continuous bead which is over 1m long - try doing that with a stick set!
I bet it has to be continuous because of the risk of cold lapping. If that was sticked, the risk would be far less.
I'd better have my say...
Mig's ok - it's fast and it's reasonable, and it's fairly easy. But there are plenty of applications where I wouldn't touch it, largely because it's much easier to get a quality weld with stick or tig. Setting up a Mig to perform up to the highest standard can be really difficult. Gas-tight Mig welds I find almost impossible. With stick or tig, it's a doddle. I find positional stick welding easier than Mig. It's certainly easier to weld round corners with stick.
However, if you have a lot of weld to lay down (or thin stuff to weld), and you want to keep it cool (or stupidly hot if you're running spray transfer on thinnish stock), Mig's yer man. And most of the time, with a well set-up decent machine, decent quality wire, and good technique, Mig can't be beaten.
