Problems Welding EMT Conduit

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I have tried to weld EMT conduit for some projects and keep burning thru the thin steel tubing.  I can't seem to get the perfect settings to run continuous without burning thru and melting away.  I am using a Lincoln ProMig 135 with .035 NP-211 flux cored wire.  Am wondering if I would be better off with .025 wire.  Any guidance would be appreciated.Thanks, Dave
Reply:Smaller wire like .025 and argon/co2 would be best,also make sure you get all of the galvanizing cleaned off..Flux core burns hotter than solid wire,so small solid wire and gas would at least give you a chance.
Reply:Can you find something else to use instead of EMT?  Even if it's free, it's a PITA to weld being galvanized.  You should be able to pick up some 1" x 16 ga or 1" x 14 ga square tubing for ~ $0.45 - $.55 / foot.  Even if you are a skilled welder EMT, is still going to look like hammered dog doo when you get done.
Reply:As mentioned conduit is a PITA to weld. You really need to get rid of all that galvi, especially if using gas and solid wire. Besides the toxic fumes it gives off when you burn it, the galvi contaminates the weld puddle and causes issues. FC helps deal with the galvi contamination some what, but it's hotter welds make it a poor choice for thin tube..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by BlueweldersSmaller wire like .025 and argon/co2 would be best,also make sure you get all of the galvanizing cleaned off..
Reply:[QUOTE=Bluewelders;4738471]Smaller wire like .025 and argon/co2 would be best,also make sure you get all of the galvanizing cleaned off..QUOTE]I have done it this way on several occasions, with good results.
Reply:I am a hunter and trapper (feral wild hogs).  Over the years I have built several airboat engine stands and prop guards, many treestands, ATV carrier racks, and such, most built with EMT and some built with chrome moly.  I weld or braze most of the conduit with oxy/act torch and mig some of the heavier conduit.  I have an unlimited supply of EMT, fence company top rail, etc..  It is either free or very cheap so that has been my material of choice most of the time.  Build and rebuild hog traps also.Trying to pulse the thin wall conduit with .035 FC and bifocal eye glasses is a real PITA and looks like crap. DaveLast edited by Davexx1; 09-29-2014 at 07:02 PM.
Reply:Last time I welded emt (flux core) I got angry at it and threw like 6 tack welds on each joint. It held well even after it got thrown a couple yards when it got into a crash(it was a roof rack holding a tire... The flatbar was a little twisted , that was what we had to make it..."I thank God for all the freedoms we've got in this country, I cherish even the right to burn the flag, but I'll tell you what, we've also got the right to bear arms and if you burn my flag I'll shoot you"-Johnny Cash
Reply:Dip it in muriatic acid to get rid of the galv. Doesn't make it much easier but gets rid of most of the dangerous fumes.GravelThe difference between theory and practice is that in theory there is no difference.
Reply:If you clean off the zinc with acid,it will usually rust unnaturally fast,but it is the easiest way to get zinc off..035 flux core on something like that would be a heart breaker.
Reply:15 cent couplers are usually the best, cheapest and fastest way to connect conduit. This situation (outdoor electrical?) sounds like plastic conduit and a little bit of glue would be in order. I'm all for welding the world together but why are you welding conduit together, isn't there be a better siuted material for your project? Clean off the zinc, various methods have been hilighted here above ^. Don't forget to wear a decent mask and avoid inhaling any white smoke from your galvanized stock, yes it's toxic and health care is expensive and time consuming. Keep us posted with photos, pliz.  Last edited by bearston; 09-30-2014 at 10:00 AM.When a welder tells you to "stick it", what do they really mean?"In a time of universal deceit, telling the truth is a revolutionary act." - George Orwell
Reply:Could you cut a short piece of conduit, then cut a piece out to get it to slip inside to give you some backing. This also helps on fit up .  Then grind the galvanize off so the arc will start easier. I tried this to see what would happen . I remembered I don't like galvanize. I did not spend as much time setting the welder as I should have, some welds are cold. But with practice I think it could be done. Left weld is with o 35  solid wire and co2 Right is first weld and center is after I adjusted the welder some  wire is 045 flux core nr211 The right and center had a short piece cut and slid inside far left was just a but joint .Good luck
Reply:Just of curiosity, I picked up a new roll of Lincoln NR 211 MP .030 FC with new tips and tried that.  There was a big improvement over the .035 FC when welding EMT, 1/8" flat and angle, etc., but conduit to conduit joints are still tricky.  I drag and wobble and keep moving.There has been much said about the dangers of welding the galvanized EMT conduit, breathing the fumes, etc..  I make no effort to remove the galvanized finish prior to welding and just make sure I have ventilation, air movement, fan, or whatever and try to avoid the fumes.Dave
Reply:The welding fumes are just part of the problem.The zinc messes with the welding process and makes it harder to get a good bead.Welding this stuff properly , you need to get every advantage that you can.If you just need it stuck together then whatever works well enough to satisfy you requirements will have to do.
Reply:you guys should see the gate I just got- .075 2x2 square tube, galvanized but thin, like emt, not hot dipped- welded with a mig, .035 wire- looks like someone tigged it, and they weld right through the galvanizing. The company is Noble Panel, in OR. Beautiful work.  I have to weld an opener bracket on it soon, they sent me a bunch of scrap to practice on.
Reply:I do a fair amount of EMT. 0.23 wire, 75-25 mix. Don't clean off the galvanizing, weld right through it. Cleaning it off with acid will only cause them to rust out fast. Butt welding lengths can be rough so I swage them. I've also stick welded a fair amount of it with 6013.http://weldingweb.com/vbb/showthread.php...ot-emt-conduit