Couple MIG'd exhaust tubing welds

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Well I had only used my welder for shaving stuff since I got the gas.  I figured I'd try some exhaust tubing I had laying around.And what do you know, a buddy of mine wants to lop off his mufflers and weld up some new ones.  So its deserving practice.  I tried to get a shot of the penetration on the inside of the tubing, but I dont know if the pic turned out too good.Machine is a Pro Mig 175, Ar/CO2 mix, .023 wire (might be .025), 15cfh, wire speed 3, voltage setting B.I think they turned out pretty good.  And its the first time I've touched the welder in almost 5 months or so.  Course, more practice is in store, but I dont think those welds would break.  I'm going to attempty to weld in odd positions, since I'm sure I'll be put in some while under that truck, lol. And I havent fully welded it yet.Criticize!!!  It aint no roll of dimes, lol.  Any tips I'll gladly take and use next time round.Lincoln Pro-Mig 175Harbor Freight cart and accessoriesAnd learning...
Reply:Looks like the machine was set prety close.  Now practice, Practice and more practice.   John  SMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:It looks like you have a hole.  Get used to filling them in because they always end up at the top.   I have done a lot of them.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Get used to welding with a mirror...it's the only way you can avoid those holes in the top that DavidR pointed out. The top against the floorboard is usually blind welding and a mirror will solve that.Anything worth doing is worth doing RIGHT
Reply:The mirror thought crossed my mind yesterday, and I thought, for just a brief second that I was a genius, lol.  Apparently not.Lincoln Pro-Mig 175Harbor Freight cart and accessoriesAnd learning...
Reply:Originally Posted by bignick31985The mirror thought crossed my mind yesterday, and I thought, for just a brief second that I was a genius, lol.  Apparently not.
Reply:I just point the gun where I think it should be and listen to the arc.  I will accept NO holes.  Its easiest to start at the top and weld down each side to the bottom.  Once you get the heat right its like a zipper.  Good fitup counts a lot.  Nothing better than a 110 mig with .023 wire and gas for that job.  I have to do my car, so I'll post pics.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Heres a few more.  I wouldnt usually weld something like this, but since its merely practice I dont mind.  I know that b/c of how the tubing fits together, it would probably not be a good structural weld.But makes for a good practice session of making a huge hunk of nothingness.The 2nd picture is actually my little bro's weld.  I set him up and let him go at it.  After a mere 5 minutes of watching me and then practicing he produced that.  Then he got bored with it and left, lol.  Lincoln Pro-Mig 175Harbor Freight cart and accessoriesAnd learning...
Reply:Originally Posted by bignick31985Criticize!!!  It aint no roll of dimes, lol.
Reply:i, by no means, am a professional welder, but fromwhat i can see, it looks like you merely spotted it on there... it shoudl be a consistant, continuous weld. try weaving it back and forth, from one piece to the other, and back again... similar to the way you would stitch 2 pieces of fabric together. it looks... well... like poo to be honest with you. sorry to be harsh, but with practice you will be decent enough... i would suggest running flat, staright beads on a piece of scrap before working o the exhasut any more. get a piece of flat steel, similar gauge to the size of the exhasut tube, and try welding straight beads on it... don't try to weld 2 things together, jsut staright lines. after you get some good, consistant beads, try the weaving pattern i explained earlier.. after that, then try on some scrap exhaust... try butt-welding end-to-end, not one slipped over the other and welded where the visibale seam is). that should give you a better weld penetration in bother pieces. mine looked about that bad when i first started, but the constant practice and trail-and-error that i do is helping me out alot. hopefully i can get some pictures of my welds up here soon.now that i remeber it... check this one out... it was a few days after i welded my exhaust up (my first project)...http://www.weldingweb.com/vbb/showthread.php?t=15404later,AndyLast edited by aczeller; 10-26-2007 at 04:32 PM.
Reply:Personally I absolutely hate welding exhaust pipe, just about the hardest there is. It seems I get about two a month wanting me to weld on their exhaust or patch a muffler. I always say go to a muffler shop it's gonna be cheaper on ya anyway. They just can't understand why it's still $65 an hour for me to weld on exhausts. Guess I should tell 'em $100, heheh.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:This is from another thread, but I guess it can be reposted here.Here is the gap.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:I'm probably going to take some criticism for this, but I'll post my thoughts anyway.  Aluminized exhaust pipe in my opinion is the one AND ONLY place to ignore the continuous weld bead rule.  I have welded a ton of it, and I've found using a series of very hot, very fast overlapping tacks yields the best weld.I would usually set up the welder for about 19 - to 19.5 volts and a wirefeed of about 30 - 35 on .035 wire.  Basically it a too slow wire feed rate for running a continuous bead on the exhaust tubing.  Then I weld the tube in a series of very closely overlapping spots.  It takes a lot of heat to burn off the aluminizing, and this seems to do the trick for me.  I've expiramented a good bit on this stuff, and that is what works best for me.  If you set the machine for the proper setting for that gauge material you will get at minimum a half inch of cold, unpenetrated weld at the start.  Then as the tube heats up it will get pretty decent.  If you try it hot enough to burn well from the start you get a molten burned through mess very quickly.  It's a combination of the nasty aluminum coating and the fact that the steel itself is a very cheap low quality grade of ERW.I will try to find some pics of some I've done...