I don't know if this is the correct spot for this but I'll try anyway. I work in a pipe/sheet metal fabrication shop. We have some 12ga galv sheet metal that they want welded up with full penetration. They told me to try GMAW which didn't pen at all, 70s hard wire. Then I tried GTAW and that broke it down but what mess. Any suggestion's would be great. Thanks
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Help with full penetration on 12ga.
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I do not think you are going to get a successful weld using Tig on that galvanized material. The zinc is going to smoke like crazy and foul the weld.
If it were me I would grind off all of the galvanized material in the area of the weld, then weld it using Tig.
The powers that be may want it completely galvanized, but that is not going to happen unless they send it out to be re-dipped after welding is complete.
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I just got done making some full pen welds on some galvanized I-beam for an overhead trolley in my shop. Depending on how thick that coating is, it can be very hard to get it all off. You might think you have it all off, but when you weld, you'll see boiling out of there.
Generally, when I weld on galvanized stuff, I prefer to stick weld it. 6010 will cut right through it and send off all sorts of awesome stuff that you shouldn't breathe in. Which is another reason why I use a stick rod, I can ramp up the ventilation fan and have another blowing right on me to get those nasty fumes away.
But still drink milk and wear a respiratory. Miller makes a really low profile one that claims to filter out not just the zinc oxide, but hexavalent chromium as well when welding stainless. It was worth the $40 or however much it cost.
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I tried hard wire but that was a waste of time. Wouldn't 6010 be a little much for 12ga galv? I'm a pipe welder by trade, so I'm familiar with 6010. Guess it would have to 3/32 rods... And heat super low. Their making it known "got to have full pen!!!"
And yes a respirator is a must for any welding!!! I also have a Miller fresh air sheild, works great but after a 8-10 hr day its alittle hard on the neck. Respirator and a fan do well. Thanks
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That's how the duct welder's do it. The use flux core or core sheild. One of the two. That stuff sucks anyway. I hate welding duct!!! But anyway, I don't think I'm going to get the penetration they want with mig. Its going to be butt seams.
I'm not sure how long the welds are other then it's 30" round 12ga, and some square to rounds. The round stuff is probably 4'-6' tall with a seam all way down.
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Pulsed Tig is not going to make any difference at all.
What you are fighting is the zinc coating on the 12ga steel. That crap boils and then fouls the weld.
Take a piece of 12ga bare steel and it will weld with complete fusion as easy as drawing a line.
Galvanized is never going to be weldable with the Tig process in my opinion.
And like others have said.....Those zinc fumes will make you very sick. Your boss needs to be told this.Dynasty 200 DX_set up on 3 phase
Coolmate 3
MM 251 w/ Spoolmatic 30A
HTP 625 Micro Cut Plasma Cutter
Victor O/A Rig
Bridgeport Mill_3 phase (w/ Acu-Rite 4 axis DRO)
10 inch South Bend Lathe_3 phase
Baldor Double Cup Tool Grinder_3 phase
Baldor 10 inch Buffer
Rockwell 12 inch Disc Sander
Cyclone 2ft X 3ft Bead Blast Cabinet
Quincy 325 2stg- Air Compressor_3 phase
Graymills Built-in Parts Washer
Rockwell/Delta Planer, HD Shaper, Uni-Saw etc.
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I agree with piniongear. Even when I attempt to tig after grinding off the zinc, I always end up finding a place with some of the foul stuff left. It's really easy I think you've ground enough off and just burnished it back a little. I am not very experienced with O&A outside of cutting and a little brazing, but could be a solution I guess. I'm still leaning towards stick. Any way you can get some test pieces and work through a welding process ahead of time? Good luck my friend. Let us know what you work out.
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Originally posted by BOBBYLEE View PostWe have some 12ga galv sheet metal that they want welded up with full penetration. They told me to try GMAW which didn't pen at all, 70s hard wire. Then I tried GTAW and that broke it down but what mess. Any suggestion's would be great. ThanksBob Wright
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