Welding up galvanized tubing...yowzers!!

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Friends,Noob here...forgive me if I placed this question in the wrong forum and sorry for the length of this post.I'm just getting back into welding after being out for 12-15 yrs and am not a professional welder by any means.  I do have several years of stick welding experience from back in the day, but am having to re-learn the trade.  I have 3 teenage boys that want to learn to weld, and we have quite a few projects we want to build together.  Here's the first one...We are starting a project welding up some 1-1/2" thin-wall (.065), mild steel galvanized EMT conduit/tubing (electrician's conduit) to build a couple of L-screens for our local high school baseball facility.  We live in a football-first town and unfortunately, improvements to our baseball facilities fall on local biz donations and dad's with skillz (and equipment).I'm pretty much a noob to mig welding and recently bought a HH 140, which I'd like to use on this project.  That being said, I'm totally willing to stick weld if it would give me better results (I also have a Miller TB 300/200 AC/DC box).FYI-I have read extensively on-line about the hazards of welding up galvie pipe and am quite aware of the precautions needed to avoid breathing the toxic fumes.  Glad I read up on that first...jeez, scary stuff.Anyhow, back to my project.  We're going to weld up the pre-bent 90 degree elbows to the straight pieces for this project, and haven't any experience welding thin-wall (.065) pipe/tubing before.  Here's my questions:1) Recs on breathing apparatus or chemical masks, for the galv fumes, that are practical while under a welding hood??2) Would I be better off mig or stick welding this type of tubing??  3) Which size wire for mig and/or which size & type of electrode would you recommend for this application??4) What machine settings would you recommend starting with whether mig or stick welding for this application?? Amperage range, DCEP v. DCEN??5) I've read about dipping the to-be-welded joints in muriatic acid to remove the galvanized coating on the metal prior to welding.  Any thoughts on such a process??Thanks in advance,DC
Reply:As far as the mask and filters, The 3M 1/2 masks and pink filters are rated for galvy. (do a search hear on filters and galvanized and you'll pull up the exact numbers (I need to head off to work in a few and don't have time to look)Mig would probably be your best bet, and I'd use solid wire/gas because of the tube thickness. FC would also work, but it penetrates a bit more and can be a PITA on thin tube. FC is a good choice if you want to weld outdoors though to help with the fumes and there is a breeze. As far as polarity, depends on if it's solid or FC. I forget which is which since I seldome ever run FC and have to swap the leads on the machine. It's listed on the package though.I always sand off as much galvy as possible first if I must mig galvy. Not a big fan of acids and steel, due to rust issues..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:1/2" thin wall isnt gonna be very strong , for a few cents more use some rigid conduit.. lots thicker wall, easier to weld and cheaper in the long run..??
Reply:What sort of use will this project be put to? Perhaps thicker walled black pipe would better suit your need.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:I always heard drinking milk after welding galvanized helps prevent fume fever...... Does anybody know from experience that this is true?Lincoln ac/dc 225/125Millermatic 211 w/ Spoolmatic 100Miller 330 a/bpDynasty 200 dx
Reply:If baseballs will be bouncing off the screens, go with pipe. Conduit is too delicate.If you can chat up your local steel vendor for sponsorship they might cut you  a break or even donate the material.
Reply:I always heard drinking milk after welding galvanized helps prevent fume fever...... Does anybody know from experience that this is true?
Reply:1/2' EMT is only minimally strong, 3/4 EMT is a lot stronger and 1" EMT is better yet.I offer three choices: Good, Fast, & Cheap. You may pick two.Hobart AC/DC StikMate LXHarbor Freight AD HoodHarbor Freight Industrial Chop SawDeVilbis 20 Gallon, 5 HP Compressor
Reply:Originally Posted by DonnieC I've read about dipping the to-be-welded joints in muriatic acid to remove the galvanized coating on the metal prior to welding.  Any thoughts on such a process??
Reply:First of all, zinc oxides are emitted as particles, not fumes. All you need is a dust mask. I once worked for 3 years straight cutting & fitting galvanized steel angle making floor grating supports in Navy ships. Never once wore breathing protection and only got zinc fever once. The symptoms are like mild flu, mostly nausea. If you get them, drink a glass of milk. Works like magic. Danger from welding galvanized parts is enormously overstated. Don't do the acid dip. The acid will simply keep on eating and your joints will rust very quickly and will be very weak. Don't use 1/2" EMT for anything even vaguely structural. A 120V wirefeed welder is a good choice for thin tubing. Inside the cover of the welding machine will be the manufacturer's recommended settings. Start with those. It will be a whole lot easier to get clean strong welds using MIG as opposed to fluxcore, also make sure your machine is set up with the proper polarity. Whatever material you choose, buy some extra and practice welding butt joints before you get into the project proper.I suggest a quality cold galvanizing spray for the welded joints. This comes in either dull (most common) or bright (will match your parts much better). Make sure to shake the can long enough and to use a heavy enough coat. Read the instructions!Good luck, post picsmetalmagpie
Reply:I would use .023 wire and attempt to remove as much of the galvanizing as possible. With that said I would try to place a fan behind you in a way that will carry any smoke away from your head without blowing away your shielding gas and leave the garage door open (big doors not just the man door). The wire feed will be a whole lot easier for this project and the welds will probably look better
Reply:Originally Posted by HeisenbergI always heard drinking milk after welding galvanized helps prevent fume fever...... Does anybody know from experience that this is true?