Welding Conduit

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I searched the Forum and read several posts about welding galvanized conduit. I have an unusual project that requires using conduit for the frame. I ground off the galvanized at least 1" from the weld area and it welded pretty good with .024 solid wire. Not real pretty welds, but plenty strong.My question, is it sufficient to grind 1" or should I grind more? I was very careful to stay out of the fumes and had no ill effects, but I have more to do tonight.Any advice is appreciated. I will post some pictures of the project later.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:An inch is good enough. Wen I have to weld that stuff, I prefer fluxcore wire. I do it with the same, .023/024 wire though, and it is fine. It can't be stressed enough to try and steer clear of the fumes of galvanized metals. Use a fan to move some air if there is no breeze. No sense in taking unnecessary risks that can be easily avoided or minimized.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Thanks, Rojo.I only have about 6 short welds to go, or I would go get some fluxcore. If they decide they want more made, I will get some for the rest of the pieces.This project is a portable, packable dentist chair for our Church's Mission Trip to Peru in September. I went to Peru last year and one of the team members made 2 chairs out of PVC. They were actually pretty good, but bulky. Our Missions' Team leader came up with a design using conduit for this trip. Since we send 2-4 medical teams a year to South America, Central America, and Africa, if we can get this right, we will need anywhere from 3-8 chairs a year. It depends on how many dentists we get to go.I will post some pictures of the finished project in a day or two. Just don't be too critical of the welds.  Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:Assuming that you are just talking about EMT conduit, I just burn through the thin coat of galvanized.  It burns off long before metal starts melting and I have found that it doesn't affect the strength or even looks of my welds.  I use it as a primary component of the deer stands I build.
Reply:Get a 3M half mask respirator and a pair of pink filters and you can weld all the galvanized you want without grinding it off.   They're available for not much money at the local welding shop or construction supply.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by Brians_45Assuming that you are just talking about EMT conduit, I just burn through the thin coat of galvanized.  It burns off long before metal starts melting and I have found that it doesn't affect the strength or even looks of my welds.  I use it as a primary component of the deer stands I build.
Reply:Originally Posted by wb4rtThanks, Rojo.I only have about 6 short welds to go, or I would go get some fluxcore. If they decide they want more made, I will get some for the rest of the pieces.This project is a portable, packable dentist chair for our Church's Mission Trip to Peru in September. I went to Peru last year and one of the team members made 2 chairs out of PVC. They were actually pretty good, but bulky. Our Missions' Team leader came up with a design using conduit for this trip. Since we send 2-4 medical teams a year to South America, Central America, and Africa, if we can get this right, we will need anywhere from 3-8 chairs a year. It depends on how many dentists we get to go.I will post some pictures of the finished project in a day or two. Just don't be too critical of the welds.
Reply:Hey Dave,That was my recommendation - to use tubing. I talked with the Team Leader today and he has agreed to try some tubing after we use the conduit that they have. I know it will weld better, look better, paint better, and I believe it will be much stronger. I asked him how many chairs he needed and he wants a total of 8, so maybe they will start looking better as we go along. Right now we are still experimenting with the right lengths, bends, etc.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:A recent post indicated that acid can also be used to remove the zinc coating.  I recently ground galvanizing off a pipe before welding and found it rather tedious to do so; the pipe was still close to round.  Would be nice if there was more info on acid removal so there was less guessing on this option.Think that the conduit would be much cheaper.  Seems steel tubing is still high so conduit would be my choice if zinc removal was easier.Chris
Reply:Originally Posted by Chris BarA recent post indicated that acid can also be used to remove the zinc coating.  I recently ground galvanizing off a pipe before welding and found it rather tedious to do so; the pipe was still close to round.  Would be nice if there was more info on acid removal so there was less guessing on this option.Think that the conduit would be much cheaper.  Seems steel tubing is still high so conduit would be my choice if zinc removal was easier.Chris
Reply:Originally Posted by wb4rtI searched the Forum and read several posts about welding galvanized conduit. My question, is it sufficient to grind 1" or should I grind more? I was very careful to stay out of the fumes and had no ill effects, but I have more to do tonight.Any advice is appreciated. I will post some pictures of the project later.
Reply:I've welded my fair share of conduit in the past, mostly for airboat propeller cages. I recently posted on this forum about using muriatic (hydrochloric) acid for removing galvanized coatings. I use the acid full strength and dip the ends of the conduit into it. Conduit has a real thin coating of zinc, and it burns off almost instantly. The best thing is it will burn the zinc off the inside as well as the outside. Once the zinc is gone, I weld with .023 solid wire and it comes out beautiful.Two safety notes:1)  DO NOT breathe the fumes generated. Do it outside in a well ventilated area. Use a small amount of acid (just enough to remove the desired length of zinc). I usually use a small rubbermaid type container with maybe 8 ounces of acid. The best safety suggestion would be to wear a respirator with acid (white) cartridges installed, solvex (or other acid proof) gloves and a faceshield. The acid will do it's job on conduit literally in a couple of seconds. Have a bucket of fresh water to rinse the acid off of the dipped item. Once your finished with the acid, if it's not too yellow you can save it for later use, otherwise dilute it in your bucket of water before dumping it.2) Conduit, by it's nature, is designed to bend easily. I would not recommend using it in any structural application. It works well for prop cages, as it only needs to support the wire mesh. For the airboat illiterate out there, the prop cage is not designed to contain the prop in the event of a failure, only to keep brush and wayward (human) limbs out of the danger zone. (There are two tubes attached to the cage that support the rudders, but they are made from 1" DOM tubing.)Miller Thunderbolt AC/DC (Sold)Miller Dialarc 250HFMiller MM251Miller MM200 (Sold)Miller MM130Miller Spot WelderVictor O/A rigMiller Spoolmatic 1 (Sold)
Reply:OK, I don't want to show any close-ups of the welds, because they aren't pretty, but here is the chair before it is painted and the pad installed. It folds up to fit into a suitcase.So far it holds me up and that's bigger than any Peruvian that I have seen (well, there was this one big guy, but I don't think he was coming to church). As long as it lasts 4 days, that is fine. They will leave it there when they leave. The next 6 we build are going to be out of 3/4" tube.Last edited by wb4rt; 09-11-2009 at 02:05 PM.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:Looks good man.  MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Thanks, DesertRider.I took your advice and used the pink 3M filters. I did not have any ill effects from the galvanized. Thank you for your support.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:Great!   They do work good.  Glad it worked out for you.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:I have some muriatic acid.  I see all you guys are MIG welding this stuff.  Any chance of getting a zinc coated coupling nut clean enough to TIG weld?Racecar FabricationOld Miller 320 A/BP TIGMiller 140 MIGwww.f-bodysport.com
Reply:I used to work in a sheet metal shop. I have run hundreds of feet of everdure bronze and never used a filter. We had a squirrel cage fan out of an old swamp cooler . I was told that I would be fired if he ever caught me welding without it blowing on me. This was in Hamilton Texas. Ha. I was the only one in there that got to work under a fan. Harold
Reply:Looks good, I agree with the guys suggesting bare metal tubing. You might even get a local powder coater to donate his services for you guys.Or powder coat yourselves. Its pretty easy I hear.
Reply:Originally Posted by StanIROCZI have some muriatic acid.  I see all you guys are MIG welding this stuff.  Any chance of getting a zinc coated coupling nut clean enough to TIG weld?
Reply:This is kind of an old thread, I suppose those guys are down and back by now.