Exhaust flange welding

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I am trying to weld a 5/16" exhaust flange to header tubing. I bought some .025 copper covered mig wire at Home Depot-it says it is for mild steel. I have my gas set at 25. I am having trouble getting good penetration. The welder is a 110 Lincoln 100 HD. I know this isn't the best welder-I have tried multiple settings. Would a thicker gauge wire be better. I do have some .035 innershield wire I could try. The polarity is set up for gas as well. http://www.pacificcustoms.com/AC750735-1375.htmlAny help would be greatly appreciated. I think I'm in over my head-I already cut up the header on my VW-thinking this would be a piece of cake-lol
Reply:Proper prep and fit up will help somewhat. I can think of several reasons why you might be getting poor penetration, wrong settings, travel speed too fast, stickout too long, improper fit up... I bet if I think some more I can find a few more important ones. Picts would help nail down some of these problems. Thin tube should be weldable with that machine assuming you have everything set up right. However you are quite limited in output and that 5/16" is pushing that machine to the max at best. Normally I'd start by suggesting you crank up the heat and concentrate your puddle on the thicker material, but since you are underpowered to begin with, and may have to drop the output even farther if you have to use a longer than normal stickout to reach the weld joint, it's tough to make any definitive call without seeing what you are working with..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:Thanks for the reply-I have taken the exhaust off the car-I am thinking like you said I am pushing the limits of this machine. Basically I have the header pipe pushed through the hole in flange (in link) and am attempting to weld around the outer circumference. I am actually considering buying a 220 machine but would have to have the electrical ran somehow.
Reply:Easy bevel the flange to give you some more "fill". You don't need a 220 welder for exhaust. It ain't structural 5/16"! Run itHTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Ok great will give that a shot
Reply:Originally Posted by DCLAMPThanks for the reply-I have taken the exhaust off the car-I am thinking like you said I am pushing the limits of this machine. Basically I have the header pipe pushed through the hole in flange (in link) and am attempting to weld around the outer circumference. I am actually considering buying a 220 machine but would have to have the electrical ran somehow.
Reply:GMAW using the 'little' machine will NEVER get enough heat to weld to that 5/16" thick flange.Never.As DSW said, when welding thick-to-thin, usually you get the puddle going on the thick piece and then 'wash' the arc and puddle just enough onto the thin piece to get the weld to 'flow' and thus weld/join the two pieces.That machine has enough power/heat to blow a hole through the exhaust tubing itself, but not enough power/heat to get anything close to a 'decent' weld onto the 5/16" thick flange. (maybe with some really-really heavy preheat)  IMHO (and by looking up some of the specs/recommendations of the 'little' Lincoln 120V MIG machines and from using a 120V Lincoln GMAW/FCAW machine).0.025 solid wire and a 'little' 120V wirefeed machine running short-circuit transfer mode GMAW are great for guage-thickness steel.  Body panels, exhaust tubing, etc.  16 guage, 14 gauge, no problem.But the machine just does not have enough power to melt into a 5/16" thick piece of steel (again, barring maybe some really-really heavy preheating with a flame or other heat source, heavy as in glowing red-hot or hotter).  The filler will melt just fine but will just be laying on top of the thick flange.  Classic cold-lap, aka inadequate penetration aka inadequate fusion.Sticking the exhaust tubing into the hole in the flange means you would then be doing a fillet weld.  Still have the problem of thick-to-thin and not enough heat/power to get any sort of fusion/penetration into the thick flange.Moving up to a 240V machine in the 175-180 'class' still really doesn't give you enough power to use short-circuit GMAW onto 5/16" thick material.  To get fusion/penetration into the 'thick' flange, even the 175-180 class machine would need multi-pass with something like some 0.045 FCAW Innershield NR-211 (or equivalent).  The 0.035 NR-211 FCAW would top out at approx the 1/4" thick workpiece level (and still need multiple passes).IMHO, you just don't have enough power/heat to get the weld to fuse/melt/penetrate into the flange.  Without doing some 'tricks' like some bevel-prep of the hole in the flange (so you have someplace to get the weld going on a slightly 'thinner' section of the flange without just piling up great big globs (ugggh!) of melted filler on top of the plate/flange (poorly penetrating pigeon poop piled on plate steel, PPPPoPS) and also preheating the snot out of the plate/flange.It's not the welding to the exhaust tubing/pipe that is the problem (ummm, the exhaust/header pipe/tube -IS- cleaned plain steel and not anything coated, right?).Post up a few pics of the 'bad' welds and we can maybe figure things out a bit better.(other option if you just can't get the weld puddle going on the thick flange may be to use a 'high-temp' brazing filler like Harris Safety-Silv 45, solidus temp goes up to ~1200F)  The best laid schemes ... Gang oft agley ...
Reply:Sorry but it's just exhuast. I don't think he will have any issues. Like I said bevel the header flange where the tube goes through and just weld it up.HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Originally Posted by fordmanSorry but it's just exhuast. I don't think he will have any issues.
Reply:I think the 110 migs get a bad rap on this site.  I wouldn't think twice about using it to weld a 5/16" flange to exhaust tubing.  They are hotter then most people think.  I have a shop full of powerful welders, but if that was the job facing me, I would probably just pull out my hobart handler 120.  I'm sure many will disagree. If you welded hot enough to fully penetrate a 5/16" piece that would be great, but it would fail sooner on the thinner tube. The penetration using a cooler run will penetrate enough into the flange without over welding the tube, in my opinion.
Reply:Okay thanks again for the replies guys I am going to pull it all apart and bevel them edges. I will let you know how it goes.
Reply:Well I took everything apart-used a grinder to bevel the edges. I switched to .035 wire. Continued  to have problems. The penetration was noticeably better-but then the wire would not feed. I then figured out that you are not supposed to fully tighten the wing nut holding the mig wire so I loosened it up. The wire then started feeding great and my welds were much improved.  Just wanted to say thanks for the input-to those of you who responded.
Reply:Took exhaust apart-beveled the edges. Also I discovered that the wing nut holding the mig spool was over tightened not allowing it to feed correctly. The machine is working good now-welds much improved thanks for everyone who responded.