MCAW sheet metal

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I've been doing a fair bit of reading about MCAW recently and it appears that, while it is more expensive than GMAW, there may be significant advantages. Are there any advantages to using it on on thin material? I saw something - that I can't find right now - about a .030 MCAW wire that's supposed to work well on 20ga sheet. I don't do all that much welding, nothing that's production work, so even if I'm spending twice as much on wire that isn't that big of an expense - especially when compared to the base metal, if I have to re-work it I spend way too much. Are there any small MCAW wires that should work well on sheet metal, or should I just stick with .023 ER70S-6 and C25?Lincoln 175HD
Reply:20ga is pretty thin sheet metal.   I'd just stick with the  .023/.025 wire for a traditional GMAW set up.   Otherwise, unless your a welding business, I'd say you're wasting your time and money for a MCAW set up.  Just my .02 cents worth........Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
Reply:I'm mostly working on motorcycle tanks and custom bodywork, which generally means 20ga and thinnerLincoln 175HD
Reply:MCAW wires produce a differently shaped arc cone(wider) than solid wire does.  They also have a different penetration profile than solid wire.  The broader arc can be an advantage if you're trying to bridge gaps in sheetmetal due to poor fitup.  A shallower penetration profile reduces chances of burnthrough, all other things being equal.BUT, the current needed to run 0.030 or 0.035" MCAW wires correctly is likely higher than that needed for 0.023" solid wire.  (I don't have charts in front of me as I type this, so don't crucify me if this isn't 100% true).  This means you'd likely need to travel faster with the MCAW wire than with an equivalent or smaller diameter solid wire.  Depending on what you're welding, moving faster might be an advantage(shorter arc on time=more efficient) or a disadvantage(harder to control=produce a good looking weld).  If you're making a series of short tack welds on a sheet metal panel to reduce warping, then I don't think MCAW buys you anything.But if you're welding a long, straight, lap, fillet, or butt joint in sheetmetal, then MCAW might help with poor fitup and improve productivity.  Most places I see this helping would be robotic, high volume welding applications.  It might help wiht motorcycle tanks and custom sheet metal, but I wouldn't expect miracles.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:I think you're talking about Harris "Twenty Gauge" wire. I remember seeing ads for it a few years ago but I think they stopped making it. I'm not aware of any MC wire being made that's less than .045.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Hobart makes some MCAW wires in 0.035".  Not sure about anybody else. Originally Posted by Silicon-basedI think you're talking about Harris "Twenty Gauge" wire. I remember seeing ads for it a few years ago but I think they stopped making it. I'm not aware of any MC wire being made that's less than .045.John
Reply:Originally Posted by slotardI'm mostly working on motorcycle tanks and custom bodywork, which generally means 20ga and thinner