Tig welding sch10 304 Exhaust manifold

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Hi guys just looking for a bit of advice on tig welding some 2.77mm thick ss sch10 304 having a bit of trouble finding a good setting and the outside weld always come out a little grey? i understand my it might be my angles but if anyone has any suggestions that would be great.So this was welded with argon along with argon back purge. settings are 0.7 pre flow, 60 amps, 2.5 down slope, 4.5 post flow. It has around 60% penertration i know my welds are not straight but my main issue is the grey colour and if i go any higher amps it just undercuts?I tried again but with pulse settings are 0.7 pre flow, 45 main amps, 65%, 5.0hz, 75 pulse amps, 2.5 down slope and 4.5 post. again i know my form is very bad but the colour just seems so dull witch i thought was due to heat but i didnt get any penetration when on these settings?Does anyone have any suggestions? as i can run a nice bead with penertration and amazing colours on 2mm stainless but i move onto this stuff and it all goes down hill? Cheers Alan
Reply:Heat isn't the only thing that causes the grey color. The slower the travel speed the more heat dumps into the work piece. In essence you want to get comfortable welding at a high heat with a fast travel speed and good gas coverage. I only see bright shiny metal on one side of the weld, make sure you clean the part being welded about 1/2"-3/4" back from where it is being welded. Same thing goes for the inside of the tube/pipe, the puddle can pull trash from the inside.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:You should bevel the tubes
Reply:Thanks for the quick reply, i have cleaned the outside of each pipe with a ss wire brush on my grinder then acetoned everything. im guessing you mean i will have to grind the material rather than just wire brush? its a little awrkward grinding near the weld as i will have a complete diffrent finish to the rest of the pipe if you see what im saying?
Reply:Originally Posted by motolife313You should bevel the tubes
Reply:You can get more weld in there and more penetration. This is for a header right? 1/8" is way to thick past that
Reply:Originally Posted by Alan.mThanks for the quick reply, i have cleaned the outside of each pipe with a ss wire brush on my grinder then acetoned everything. im guessing you mean i will have to grind the material rather than just wire brush? its a little awrkward grinding near the weld as i will have a complete diffrent finish to the rest of the pipe if you see what im saying?
Reply:Originally Posted by motolife313You can get more weld in there and more penetration. This is for a header right? 1/8" is way to thick past that
Reply:4.5s is not nearly enough post-flow, especially if you are traveling slow with lower amperage to boot.  I hope you're not using anything smaller than a #8 gas lens.   If you using anything more than 1/8" arc-length you are shooting yourself in the foot.  machine settings are only one thing, user technique is another.  Granted I've not done 2.77mm SS, that's around 0.110".  60A seems too low for that.  For 16ga (0.062") I usually use around 45A.  What is your actual arc length, and how fast are you traveling using actual length and time units?Last edited by Oscar; 11-01-2015 at 03:18 PM. 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:I've done my share of stainless exhaust stuff and for what it's worth imo your wasting time trying to achieve 100% pen. Just simply unnecessary.  Forget beveling the tubing, it'll only make it more frustrating. He's not building a boiler moto.
Reply:Beveling will also help you make straighter, more even beads. It gives the puddle something to sit in. If you're welding on a flat surface, especially if you're welding cooler than what would give full penetration, the puddle tends to chase slight imperfections on the base metal. Another way to reduce the gray color is to let the part cool between passes, or if you are doing it in one pass, you can weld it in quarters. I would recommend trying 85-90A. It always seems counter intuitive to turn the heat up on the welder to reduce your heat input on your part, but it has to do more with the speed that you weld than the actual amperage setting on the machine for how much heat you are putting into the part. You're already back purging, so you might as well get full penetration on the part. It'll help prevent the welds from cracking later on. You don't necessarily need an open root on this thickness of metal, but you should knife edge the bevels and insure you're getting fusion before you dab the rod in each time. If you're so inclined, you could just run a quick fusion pass with no wire, but I would definitely do that in quarters with at least 4 good fusion tacks so that it doesn't pull too much. Then run your normal bead on top of that.
Reply:Beveling will also give you a better chance to have a better looking bead aswell. I don't weld stainless much but on 1/8" id think you'd want 100 amps for that
Reply:I just re-read your post and in reference to the undercuts, you just need to add more metal. You need to watch the edges when you add your metal, and you need to push the rod into the puddle and watch it fill the undercut. When I say push, I mean ever so slightly, almost just letting it melt itself into the puddle just a little longer, but melt into the puddle, not away from the puddle as it would naturally do. Beveling will also help this. When you strike up initially, make sure it's making the puddle size you want, which may mean you are sitting there for a moment before adding metal in. Then your speed is determined by being able to keep the puddle the same size. just remember that you are not melting the filler rod with the torch. You melt the base metal into a puddle, and the puddle melts the rod.
Reply:Originally Posted by motolife313Beveling will also give you a better chance to have a better looking bead aswell. I don't weld stainless much but on 1/8" id think you'd want 100 amps for that
Reply:Thanks for the replies guys some really good advice, im currently using a standard #6 lens but i have ordered a #8 gas lens just waiting on that arriving, im trying to get a 1mm arc gap but as my hand isnt that steady i struggle to maintain it on a round surface at the moment (im hoping i will improve). Also how far should my tungsten stick out its 1.6mm? as for speed by inch im sorry i have no idea but im only doing around 1 inch at a time to try and keep some form so i might have a go at timing tomorrow. Most of the joins have a bevel its only the straights i have not done so im sure that can be applied, i really would like 100% penetration as its a top mount mani on a 400bhp car so i think it will need it. As you said i need to run more heat and now understand i need to apply more filler to compensate for the undercut so i will have to try this tomorrow but it always ends up very wide and messy so i guess thats all down to practice?
Reply:What size filler rod are you using? Hopefully it's 3/32 or smaller. I forgot to address that. 1/8 is going to give you problems trying to melt it on this thin stuff. When applying more filler metal, don't concentrate so much on the fact that you are adding more metal. You are more like allowing the rod to sit in the puddle longer and you are watching the sides of the puddle until you see the puddle take the size and shape you want, like filling in the undercut if you see any as you are going. THEN pull the rod out for the next dab. It could be a difference of fractions of a second more than what you are already doing. Also, keeping your tungsten sharp and close and pointed directly at the center of the joint can reduce undercut.
Reply:The filler rod and tungsten are both 1/16 sorry i thought i had added that in the original post. i always try to keep a sharp tungsten as iv tried with a blunt at it makes it even harder aha i understand what you are saying but always struggle to see what the weld is doing but i only have the tungsten stick out 2-3mm should i have it out further so i can see more? if so how far? and maybe a bigger cup?Thanks for the help
Reply:They do teach tungsten stick out and profile for sharpening in school, but in the real world, I've never seen it come up except for setting up robotic welders, and the tungstens we used for those are pre machined. The stick out is really dependant on gas coverage. If you are using a gas lens, you can stick it out more than the regular gas defusers. I gauge my stick out by the physical limitations of the cup to tip angle. If I have a deep bevel and open root where I would need to articulate the tungsten to point to either side of the bevel, I'd want more stick out so that I can keep the tip close. If I'm walking the cup on a pipe or tube, I am almost constantly adjusting the stick out  between passes so that I can keep using the same torch head angle with the deposited weld metal filling up towards the surface. When I have the weld flush with the surface and doing the cap, or doing a weld on any flat surface that I'm going to walk the cup, my stick out is almost nothing, maybe 2-3mm. Any time I'm freehanding, which looks like you are doing, I roughly put it too about 1/4-3/8". 2-3mm for free handing seems a little too close. As far as not seeing the puddle, what lens are you using? If it's a fixed lens, I highly recommend getting a gold lens. They're probably about $10-15 for the standard sized ones and maybe slightly over $20 for the larger ones. You can see much better and one you try it, you'll probably never want to go back to a green one again. I've been hearing something about some blue lens or filter lately that might be worth checking out, but the gold lenses already have a blue tint to the color. I do a lot of TIG welding under 100 amps and always run with  shade 9 lens or setting on my autolens, but it might be too bright for most people who go with a 10. Also position your eyes to be able to see under the cup if possible.Last edited by TheBFA; 11-01-2015 at 06:27 PM.
Reply:With a standard #6 cup without a mesh diffuser, you should keep the stickout to about 2x the electrode diameter.  So what you have right now is about the most you can get unless you want gray to be your new favorite weld color .  Normally you'd be able to do 3x the electrode diameter, but since you're traveling around the circumference of a tube,  argon dissipates MUCH faster into the surrounding atmosphere than a flat butt joint.  The #8 gas lens would be bare minimum in order to have extra coverage on your side.    With a #8 gas lens, you could do about 4-6x the tungsten diameter, but at this point it is no longer a "gas saver", because you have to up the flow to compensate for the argon dissipating quick.  No less than about 18 CFH with 3-5x the tungsten diameter for stickout would be my preference on tubing of that diameter.  A bigger cup is not necessary, when you have elevated your welding skills, but if you're not familiar with SS, get a LARGE diameter gas lens.  Think #12 or larger.  You can get a #18 Pyrex cup kit for around $50-60.  Once you're a pro, you won't need it, but right now....  .  Also, this is why you never practice on an actual project.   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:3 inch schedule 10 is tough to get good color on a consistent basis. I've been doing it for 35 years and mine come out dark red pretty often. It's not really worth fretting over, that weld is just as good as another, especially for an exhaust. Brush it off with a stainless wire brush, done.
Reply:Ok well i have a #8 gas lens coming in the post so i will see how that goes, i wasnt really fretting over the colour it was more of a concern when i see others welds and they have all these colours and mine is just grey it makes you wonder why and if its correct?So when its all here im going to try again with #8 cup 3-5x tungsten stick out, around 18cfh and a little more heat i will post my results hopefully tomorrow night.I also do agree that it was a bad idea taking on this project with little practise but without doing it i wont get any better and its for a friend not a customer
Reply:I use a #12. Run as fast and narrow as you can on that thin stuff. It turns grey because your weld is still red hot when it gets out of the argon. You have to keep the heat input as low as you can. Not saying run cold, but you have to run fast. The slower you go, the hotter the pipe gets.
Reply:When we run schedule 10, they always butt it up flat end like yours is. I like to grind out a little valley like the ends were bevelled. Our welds have to be full pen, and grinding that valley helps with that. It probably doesn't matter on an exhaust.
Reply:Get some .045 filler....Huge difference..But if the tubes are "flat" to each other...nice fit up with ZERO gaps... You can do this whole job with NO filler.Bu if filler is needed smaller is better...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:Originally Posted by motolife313Beveling will also give you a better chance to have a better looking bead aswell. I don't weld stainless much but on 1/8" id think you'd want 100 amps for thatIt's 1/8". That's pretty thick. I would think 70 amps would be bare minumum for me.