Maybe a stupid question...why smaw on heavy equipment repairs?

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Maybe this is a stupid question but I can't really find the answer to this.On this forum and others I've seen a few repair threads where some operator has completely destroyed a bucket or all the teeth on a big piece of heavy equipment like a trackhoe, bulldozer, etc and on every one of these threads the solution has typically been to use a cutting torch or arcair to blast away any damaged/rusty metal and repair the area for some new teeth or plate.  Then everything gets stick welded back together.Is there a particular reason for this, other than that from what I've seen dollar per amp you can get a bigger stick welder for cheaper?I'm wondering because I repaired a Komat'su trackhoe that was missing a couple teeth on the bucket and had a couple small cracks on the remaining teeth.  Everything was cut back to fresh metal, ground clean and migged and it seems to be holding up fine over 6 mos and lots of jobs later.  Mind you, the mig machine was a 400A lincoln unit with an LN-7 feeder and I know the operator isn't nice to this thing, but is there any sort of different expectation of repair quality using mig?  Or is it just a cost effectiveness issue?  At the time the 400A lincoln mig was the biggest machine I had at my disposal.Last edited by greenbuggy; 10-04-2010 at 03:06 AM.
Reply:I use FCAW often on repairs. rarely mig.   The SMAW and FCAW with the proper electrode selections produces a much better notch toughness weld for heavy beatings.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Maybe because when you weld heavy equipment, you're usually outside and it's often windy and SMAW machines are more commonly found in those situations?
Reply:i mostly use FCAW or MMAW. most of my repair work is onsite so gas shielding is out of the question. I reckon i can lay down far more filler in a given time with the right FCAW wire than i can with MIG.sometimes i will use stick if its a smaller job or a hard to get to joint. or if its not efficient to change/buy a new roll of flux cored wire for the job. by the way do you mean stick welding when you say SMAW?  because i thought you were talking about sub arc. where i come from MMAW stands for manual metal arc welding (stick),  and SMAW stands for submerged arc welding.Last edited by stamp; 10-04-2010 at 05:14 AM.
Reply:ok i just did a quick check and it turns out that stick is called SMAW in the states. sorry for the confusion. i was wondering how the hell you would do repairs using a sub arc machineLast edited by stamp; 10-04-2010 at 05:16 AM.
Reply:Green, most of the heavy equipment shops I have worked in were just that, heavy equipment shops and not welding shops, so the equipment selection was limited to what the equipment owner got the biggest bang for his buck out of.  Most welding shops also do just that,  and are not really equiped to do heavy equipment repair, so it is kind of a peaches and apples kind of thing.  A well equiped welding shop would probably choose a different process than the  guy on a service truck, because they  use what is available and are capable to use to get the job done and  the equipment back on the job.  A lot of very good service techs on service/crash  trucks cannot weld very well, (thats me), because they have many different job demands ( hydraulics, maintenance, wiring, vandallism, fire, operator damage, etc...) to contend with, but can do a good enough job to keep the equipment working till it gets back to the shop for maintenance and a  permanent repair, if the repair exceeds the shops capability a welder is called in to do the job properly for a safe, permanent repair..I'm spending my Kids inheritance, I dont like him that much anyway!!!!!!Enuff tools to do the job, enough sense to use em.Anybody got a spare set of kidneys?  Trade?
Reply:Ok, good to know.  Getting my shielding gas blown away wasn't really an issue as I extended the boom so the bucket was at least 6' inside the garage door of the shop, but that makes a lot of sense.  And yeah, by smaw I meant stick not a submerged arc process (I've never done sub arc but saw a TLC program that featured it and it looked pretty cool.  All the welding was done by a robot on a track)
Reply:I'm not very familiar with submerged metal arc welding but from my understanding, it's an automated process that's only done by robots because since it's submerged you'll never be able to see what you're doing.  From what I understand about MIG welding, is that originally it was created for welding sheetmetal because the wire feeds out in a continuous fashion making for a prettier weld.  The AWS (American Welding Society) doesn't even really acknowledge MIG welding as a process to be used for any critical type of welding. Flux Core for it's strength, and Stick for it's ability to be used in the field, on the other hand is what you'll see a lot of these days in construction and heavy welding projects, it's been my experience that Flux seems a lot hotter than MIG and the penetration is a lot better (try both types of procedures on the same scrap metal one day, and after you flux core, mig welding seems like your just squirting some JBweld out of the plastic tube). Everyone else is dead on with Stick welding and shielding gas in the field. I would keep aware though that you can still kinda weld with only some shielding gas present when miggin' of fluxin' but it makes for not as good of a weld as if you were getting all the gas shielding like you would inside a shop.
Reply:Originally Posted by stampby the way do you mean stick welding when you say SMAW?  because i thought you were talking about sub arc. where i come from MMAW stands for manual metal arc welding (stick),  and SMAW stands for submerged arc welding.
Reply:Originally Posted by ArmadilloI'm not very familiar with submerged metal arc welding but from my understanding, it's an automated process that's only done by robots because since it's submerged you'll never be able to see what you're doing.
Reply:lots of good info in here. I would have guessed that smaw or fcaw is better because getting the pieces "clean clean" would be difficult or time prohibitive. Something with a flux to clean out any impurities left behind. Our army welder had stick for portability. His trailer could be dropped off and he would wander around the motor pool fixing our equipment.Weldanpower 225 G7Ironworkers Local #24
Reply:Saw or a similar process was done on Navy ships and may still be.  The process was used on external decking to provide a permanent no slip surface for sailors and equipment to no fall overboard so easily.