Mig versus Arc

[FredH]

First , this is not about which is better , everyone has their own opinion , which has been stated here many times before , and their own preference .

Seen something really cool though tonight on the National geographic channel about Caterpillar building their 777F dump truck . While the initial frame is welded using a robot welder , afterwards welders come in and get the hard to reach areas as well as key areas for reinforcment . It showed 1 guy welding this one place , ( its were the rams for the dump attach to the frame ) , Back and forth , bottom to top then all over again . Filling in this area over and over again , Welding right over the top of what he had done on the previous pass .

Now don't quote me on this but they said ( at least I thought the did ) , something about in excess of 700 lbs. of welding wire into I believe the frame alone . Holy Cr!! . That is alot of wire . How many sticks if arc .

Now I like both , so I have my own opinion and preference when to use what , is was though , very interesting to see them using mig on very thick metal , which on some welding boards similar to this board , is very taboo .

If you are able to catch the show , very interesting . ( Better than re-runs anyway ) .

Fred H.

 

[plastikosmd]

I wouldnt say taboo, as you are talking about industral strength MIG welders, not the off-the-shelf mini hobart/lincoln/miller/whatever. if you look at what the 'average' guy will have..usually the lincoln tombstone at 200plus amps, and a smaller wire feed welder..if lucky 175, but more likely less. (sure some of us got a lot more..but just talkin your entry level stuff) ...that is where a lot of those discussions end up. if you gotta stick thick plate to thick plate and you got the above, you either gotta know what your doin with the mig at lower amps, or you can get away with a bit more with the arc. seeing more and more mig on the structural steel buildings around me also..tho still see a lot of arc..probably a portability issue? dunno how the get the wire to feed..maybe a spoolgun....

 

[RobS]

Don't mean to detour your thread but the Cat 777 caught my eye. There is a fab shop near us that machines some of the frame pieces for those and the other big Cat stuff. A buddy of mine used to work there. They have a horizontal boring mill with a table the size of a semi. In fact, to load the steel, they literally drive the semi onto the table and raise the steel, then drive the truck away. Lower the steel then start cutting. I almost wonder if this isn't where the show was filmed? Did they say?

 

[Jim_in_Omaha]

Heres a youtube about welding with flux wire welders. 30 hours for each beam joint. 90 tons of wire in the building.

YouTube - Welding Beams for Sky Scrapers

 

[FredH]

The show was Ultimate Factories as mentioned on National Geographic . Actually kind of screwed up , thought show was over and missed the last 1/2 hour .

Think it was at the Cat factory but were ??? Missed that part .

Also know what was said about industrial versus over the counter welders that most might buy . My brother just bought a lincoln 255C . With additional spool gun for aluminum welding , ( besides standard gun for steel , so he does not have to change liners ) tanks , etc... , he laid out close to $3000 ( there abouts anyway ) . He also got a whole bunch of other stuff at same time , some free ( gots more gloves than he knows what to do with ) , but welder sells for around $2000 plus additional for spool gun . More welder than I would know what to do with , but working in his shop maintaining equipment on 2 farms he needed something to replace his old miller(matic)35 that had more wire ran through it than I would use in a lifetime .

The show though was pretty cool , talk about the ultimate fabrication . Being a Truck driver / Owner operator , my preference is actually Duck Tape .

Fred H.

 

[ray66v]

What they showed is very heavy duty flux core welders that are out of the reach (price wise) of the common man. There is no comparison between those and the machines people have at home. A consumer grade mig will, with proper technique, weld heavy steel. It is however, not an efficient way to do it.
This can be demonstrated in a simple side by side test using both mig and stick machines on plate steel. You will quickly find the stick welder will deposit metal much faster and will likely have a longer duty cycle, (the amount of time you can weld at high amperage without overheating the machine). If you weld thick plate with a consumer grade mig plan on taking a lot of coffee breaks as the machine shuts down to keep from burning up. This also increases the size of "the heat affected zone" because you can't weld it and get it done fast. That will result often in increased distortion and warpage.