16 gauge exhaust duct

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Doing my first on site welding of 16 gauge exhaust duct using .35 flux core this week. I have a older lincoln SP125 right now that I've been using the past few weeks. I was thinking about purchasing the 140. I was curious if you guys think I'd notice any difference between the 2 machines.Also any tips on welding 16 gauge would be appreciated.
Reply:practice on exhaust scrap first because 0.035" flux core normally has to be run very hot to burn the wire to begin with.  You might find that you will need smaller diameter wire.  If you weld anywhere near a bend where the exhaust tubing is even thinner than 16ga, you'll burn through immediately (if you're not careful).  The tigher the bend radius, the thinner the material gets and the easier you'll burn a hole right through it.  Practice, practice, practice.  The more tacks, the better because depending on the tubing diameter, you'll likely only be able to weld about 1/2" before the heat buildup melts a hole in it. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Originally Posted by Oscarpractice on exhaust scrap first because 0.035" flux core normally has to be run very hot to burn the wire to begin with.  You might find that you will need smaller diameter wire.  If you weld anywhere near a bend where the exhaust tubing is even thinner than 16ga, you'll burn through immediately (if you're not careful).  The tigher the bend radius, the thinner the material gets and the easier you'll burn a hole right through it.  Practice, practice, practice.  The more tacks, the better because depending on the tubing diameter, you'll likely only be able to weld about 1/2" before the heat buildup melts a hole in it.
Reply:Originally Posted by WookieWeldingmandrel bent tubing is pretty much the same thickness throughout the bend radius
Reply:exhaust ducts and exhaust pipes are two different animals.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:Originally Posted by boatbuoyexhaust ducts and exhaust pipes are two different animals.
Reply:My guess is commercial vent hood ducts. They're required to be a minimum of 16ga and seal welded from hood to fan flange on the roof. Major pain to do in the field since good joints are hard to do and a combination of wind and roof work make MIG difficult at best.   I'm in the middle of doing one now. Personally I've given up on trying to flux core and just use stick with my Dynasty or Legend. It's the one time I wish I had a Maxstar 150. That Dynasty is kinda heavy to tote up a ladder and my Legend isn't as good at low amperage work. But I don't do enough of them to justify buying a welder just for that work. I tried that years ago getting a Millermatic 130 for my second install and then never doing another one till I'd gotten tired of the lower duty cycle and trading it for a 175 and later my 252.  I've also gone to using 14ga to make it easier. Not that much more expense in materials but much easier field welding.Last edited by irish fixit; 07-08-2013 at 10:29 PM.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Originally Posted by irish fixitMy guess is commercial vent hood ducts. They're required to be a minimum of 16ga and seal welded from hood to fan flange on the roof. Major pain to do in the field since good joints are hard to do and a combination of wind and roof work make MIG difficult at best.   I'm in the middle of doing one now. Personally I've given up on trying to flux core and just use stick with my Dynasty or Legend. It's the one time I wish I had a Maxstar 150. That Dynasty is kinda heavy to tote up a ladder and my Legend isn't as good at low amperage work. But I don't do enough of them to justify buying a welder just for that work. I tried that years ago getting a Millermatic 130 for my second install and then never doing another one till I'd gotten tired of the lower duty cycle and trading it for a 175 and later my 252.  I've also gone to using 14ga to make it easier. Not that much more expense in materials but much easier field welding.
Reply:Originally Posted by DVtechYou're guess is right. Commercial exhaust grease ducts. I mostly work in mall food courts and small restaurants, all ducts are 16ga. Most fittings are made in shop. On site welds are 1" welded flanged joints.
Reply:We had a similar project last year to do. Bought a miller  multimatic 200,the guys loved it, select the gauge of sheet metal, and squeeze trigger, get a small bottle of gas, go to it.
Reply:They didn't make the suitcase type migs back when I tried to tool up for this type work. Now days it doesn't make any sense for me to by a small portable mig. Mainly because it's rare for me to do portable work and most of the portable that I do is way to heavy for a small mig. I've got a Trailblazer 302 EFI sitting in storage right now waiting for me to get time to build my new truck. But the trucks not reached high enough on the to do list yet.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:We do a lot of these.  Bend a 1" flange on them and weld them MIG downhill in the shop and use 3/32 6011 in the field with a 110v Miller.Beck's Welding and Fabrication, Inc.-Misc. Metals Fabrication & Installation-
Reply:Originally Posted by OldSchoolPSDWe do a lot of these.  Bend a 1" flange on them and weld them MIG downhill in the shop and use 3/32 6011 in the field with a 110v Miller.
Reply:Not that much difference between the SP125 and the 140. You may want to try .030 flux core, easier to use with 16ga.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Way back many years ago when I got my first mig I used to get some 0.023" flux core. It's worked a treat on thin metal like this. I've not seen any for a long time but then I've not been looking for it. It is a pain to feed. Need a pretty short lead or a spool gun. Looks like SIP still sell it but I don't know where to get any in the US anymore.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Wild, I've never seen .023 flux core. Harris used to make an .030 metal core wire they called "Twenty Gauge" but I never saw any in person. I guess it wasn't that great.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:That's the only time I ever saw it. My first MIG was a SIP and I got the wire from the US parts source. I no longer have any info on them and I can't seem to find a US based distributer for them in a quick search. Lots of UK sources but no US sources pop up.   I do know that there flux cored wire is some of the best I've ever used for thin stuff. I really liked that small wire for 16ga work. Back then I had to work outside so flux core was all I could use. I used it to make the tool boxes that are on my current truck (back then it was my dads truck).   It looks like Esab makes a 0.030" wire that supposed to be good down to 18ga but I've never tried it.   I did finally find a couple of listings for wire that small but from places and brands I've never heard of before.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm