Please critique my tig welds

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I welded a new flex pipe to a used SS downpipe.  Used 1/16 red tungsten and 1/16 308 filler rod.  Lincoln PT185 set to 70amps with 7 second post and 13 cfh at the cup.  I wiped everything down with acetone, but in retrospect should have perhaps wire brushed the new flex pipe.  The flex seemed to provide much of the filler material, not on purpose though, my filler feeding is a bit slow and erratic. I back-purged with a separate argon tank set at about 5 cfh.  The weld area looked quite bland compared to the nice gold tig welds I've seen.  It looked a bit better once wire brushed.  This is my first real tig project, so don't hold back! Thanks Attached Images
Reply:too much heat is what turns stainless welds gray.  Move faster, its not easy, it takes practice.as you stated, you should have sanded down the flex pipe as well.  The cleaner the metal to be welded is, the more luck you will have.With something that thin i would have probably been around 50 amps.  I set my pedal so that i start off floored, and let off as i go.  I dont like setting the machine to 70 amps, and only using 50.  You lose some of the adjustability of your current by setting the machine higher than you need.Other than that it looks like your on the right track.Last edited by drivethruboy54; 06-13-2008 at 01:49 AM.
Reply:Looks like you got that done real nice. I hope my first Tig project turns out that good.Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:whats it for??
Reply:Thank you Drivethru, that makes sense.  I was pedaling back once I got the puddle going but definitely wasn't moving very fast.  I hadn't thought about how the machines amp setting affects the pedal's resolution too, but of course makes sense, thanks for that tip.  In past practicing I found myself without enough heat and so by the time the heat had built up I had vaporized the metal at butt joints, but I certainly could have turned it down on this project.  How badly does this overheating affect the integrity of the weld/metal?This btw is a aftermarket 3" down pipe for a MkIV VW Jetta/GTI with a 1.8 turbo motor,stock turbo, Revo chipped, front mount intercooler and a bunch of other bolt on stuff.  The chip(more timing and 6psi more boost) is good for 205 whp/218 ftlbs an additional 40whp and 60ftlbs on our dynodynamics dyno.  This downpipe helps the turbo spool a few hundred rpm soon for a more aggressive torque curve.  Here's the stock and fixed upgraded DP and today's welding project, this one for an audi 2.0T in a jig I made up. Attached Images
Reply:for what you doing, the welds are fine.  Just make sure there are no holes in your bead, the color will come with time.
Reply:I like'em..For a first timer..Not bad..Not really what you would want to start on but you did a good job!More seat time and you'll be tigging with the best of'em.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Crank up your argon from 13 to 20, maybe look into getting a gas lens, that will help with the oxidation and some of that small porosity.Looks good other than that, newbie!!!I r 2 a perfessional
Reply:Thanks for the help guys, I've done a fair amount of practicing on scrap, but I figured I might as well jump in on some real pieces too.  Today I worked on my other Downpipe.  I seemed to do well on the flange connections, helped I'm sure by their thickness.  I set the machine at 100 amps max, concentrating most of the heat on the flange.  I felt quite good about the results.  I seemed to loose my edge(it just looks ugly!) when it came to the center pie cut sections of .065.  I dialed back the amperage to 50 but my welding endurance seem to wane as I dipped the tungsten quite a bit.  I'm wondering whether 1/16 filler rod was too thick and/or that I was dipping too often as the bead seemed to really pile up. I was trying to keep the heat down as again my welds were quite grey.  Haven't had a chance to look inside the tube as I wanted to let it cool in the jig.  I am using a very small cup, I guess I should step it back up and/or crank up the gas as suggested. Attached Images
Reply:The one thing I immediately noticed was the tungsten stick-out...or lack there of.  You must be almost blindly dipping your filler if your tungsten is nearly flush with the cup.
Reply:I thought my eso should be small due to the small gas cup size.  Since I was using  a fixture that allowed me to move/rotate the work around as needed, I could always be in a position to see the puddle from the side, but I'm sure it did affect it. I did use the same technique on the flanges too.  Do I need filler rod on .065 butt joints that are well fitted and then filler when fitment isn't quite so tight?
Reply:I would say that you are using a 5 or 6 cup... so your eso should be about 3/16 IMHO...
Reply:you dont need your tungsten that sharp of a point as well. make sure when you grind it, grind it tangent to the diamond wheel or whatever you use so scratch marks run up and down not around. never regrind a contaminated tungsten either. snap it off and make a new point on it.looks not to bad for first time.
Reply:Thanks for the help guys! I put my gas lens collet and #6 cup on to do the  O2 bungs, and got much better results though it's a bit tighter working space than using the smaller 4.  My backpurging came out well and the inside of the pipe showed nice penetration without any sugar.  Just need lots more practice!
Reply:What part of town do you weld in Mike? 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:Your looking really good for this being your first project. good to see another Vw gearhead on here.   You ever come around the 1.8T forums on the Vortex?
Reply:Originally Posted by tanglediverWhat part of town do you weld in Mike?