Help with welds and discoloration...TIG

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Hey guys.Fairly new to TIG welding and I am working on some stainless projects.Details...Shedule 10 pipe  304SS (both 1.25" and 1.5")309SS 3/32 filler at the stainless tube to mild steel flanges308SS 3/32 filler for the remainder3/32 2% theorated tungsten with a #8 cup.no pulse and 10seconds postflow of argon purge.running at 100 amps for the tube and 140 for the flange and using peddle control to regulate it.In some spots the fitup wasnt the best, but it generally is fairly tight.Any tips or techniques would be appreciated.Thanks,Matt
Reply:Suggest you study the rather exhaustive thread below:home made twin turbo the "right" way?http://weldingweb.com/vbb/showthread.php...ghlight=headerBlackbird
Reply:Thanks!Reading now!
Reply:at first glance I would say torch angle, and contamination are the main issues. Having had similar issues I can say it just takes practice when welding oddly shaped round exhaust stuff.
Reply:How many actual hours of hood time do you have ? Not time in a shop but time welding.
Reply:How does one get spatter on stainless with GTAW? It looks like you need a lot more practice before you try a job like that unless it is practice itself. Does the inside look anything like the outside? If so it aint going to give you the maximum performance and life that it could.Your beads need to be more consistant. Travel rate, torch angle, stand off, and amps all matter a lot. Did you have a purge on the inside? I'm betting the answer is no or not enough from the look of the welds.You just need more practice.Two turn tables and a microphone.
Reply:yeah man, the fit up is also very important to get the good looking welds too, nice straight cuts with beveled edges will go a long way to giving the potential for nice even welds without having to put too much heat into it... it's a challenge for sure..., I see dave linked to my saga of a thread  lots of ideas there to get good fit up though, I need to update it as to where I am now... built a new beveler too... it takes time & a lot of practice....miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Originally Posted by PangeaHow does one get spatter on stainless with GTAW?
Reply:Also not really a good idea to let Stainless anywhere near that rusty old work bench.
Reply:Originally Posted by PangeaHow does one get spatter on stainless with GTAW? It looks like you need a lot more practice before you try a job like that unless it is practice itself. Does the inside look anything like the outside? If so it aint going to give you the maximum performance and life that it could.Your beads need to be more consistant. Travel rate, torch angle, stand off, and amps all matter a lot. Did you have a purge on the inside? I'm betting the answer is no or not enough from the look of the welds.You just need more practice.
Reply:Originally Posted by Jay OHow many actual hours of hood time do you have ? Not time in a shop but time welding.
Reply:Originally Posted by Baila La PinzaAlso not really a good idea to let Stainless anywhere near that rusty old work bench.
Reply:Originally Posted by shlammedActually, or is that just a joke towards me?My shop is at a farm, and i pulled this out of a laneway as opposed to having to clamp directly to the project.... it is on my list as well.Thanks Guys!
Reply:When i look at it i see carbide precipitation, less heat!
Reply:Try a bigger Gas Lens and Gas Cup. Get the diffuser with the screen. Also may want to leave Gas Cup with post flow for a good 5 seconds or more on the joint before pulling away.Try as mentioned a little less heat as well. BUT my thought is you are using a small diameter cup and the single barrel style collet body. GET the Screen diffuser,.
Reply:Originally Posted by shlammedActually, or is that just a joke towards me?My shop is at a farm, and i pulled this out of a laneway as opposed to having to clamp directly to the project.... it is on my list as well.Thanks Guys!
Reply:Originally Posted by SpeedyGlasWhen i look at it i see carbide precipitation, less heat!
Reply:If you are using a pedal by all means use the peddle and slowly back off the heat while continuing to travel your torch. This will create a DOWNSLOPE condition and give you a nice tail out. For that bead width this should all happen in 3 to 5 seconds. Coordinate your travel with the sloping DOWN /foot pedal.
Reply:Thanks Don!Also, I have been using a stainless brush that i exclusively use on stainless as well as a rag with acetone to clean cutting fluid off of the workpiece.Even though I use the acetone on the part i occasionally get some smoke from the inside of the pipe where i missed some cutting fluid.  Is this going to sugar my welds, i havent been able to see in these areas which is why i couldnt clean it out.
Reply:The only thing that will sugar your welds is Atmosphere. Sugaring is GROSS OXIDATION of the weld puddle. To prevent this you have to BACK PURGE with Argon. Simply cut out cardboard the dia of your tube.Tape both sides with duct tape. tape to pipe. Insert tube / hose from regulator damm up exit but leave a 1/4 hole to vent. tape up tightly all escape holes.The oil (hydrocarbons) will effect discoloration by burning. The biggest threat may be screwing up the metallurgical composition in some cases. However the most visible would be a burn mark or soot were the oil was. The oil may also cause porosity and lack of fusion. The porosity will come from the oil burning and off gasing.Yea you do not want oil or grease anywhere near your weld. Remember welding 101 no rust,paint,oil,grease..........Last edited by Don B; 03-21-2011 at 03:39 PM.
Reply:Not stainless, but this is a practice for consistency and cleanliness to help my general skill.  T joint with mild. 1/8 mild, 110a plus pedal, 3/32 filler. Not my welding table, this was in my class. I can do this on mild all day now, which is good as king as it's a solid weld.Last edited by shlammed; 03-21-2011 at 09:57 PM.
Reply:You definitely have serious lack of sheilding problem in the first set of pics. Have you checked your set-up to make sure your getting flow from the torch and you don't have any leaks? And a project like that needs to be purged if you want it to look worth a damn IMO.
Reply:Originally Posted by SR20steveYou definitely have serious lack of sheilding problem in the first set of pics. Have you checked your set-up to make sure your getting flow from the torch and you don't have any leaks? And a project like that needs to be purged if you want it to look worth a damn IMO.
Reply:Sorry for the late reply, yes, I was being serious about the work bench. As said putting something non ferrous on top of it is ideal, depends what you're doing, but I would at least grind it down to shiney metal. Other things to watch out for are grinding sparks, If you cut/grind and the sparks hit the stainless they will wreck it.  Snapping the torch away to finish your beads is how it's done with lift/scratch start tig, but if you've got HF with slope/pedal, then you want to run your bead over the top of the start position a little, then either hold the torch still (can rest the cup if you like) hit the slope down and dab one last dip just as it starts to ramp down (to prevent a pin hole), or hit the slope down and move  forward, giving you like a comet tail finish. Another way to finish the bead (again, like a comet tail) is to not ramp down at all, when you've welded slightly over the top of the start of the first bead dab a little filler and push it quickly forward (so that it doesnt penetrate) untill the filler runs out, then hit the button to stop the arc. Other people might have their own ways of doing it, but I use these three methods, depending what welding set I'm using. (and the mood I'm in ).BTW you don't need to spend loads on a dual flow reg, just use the one you've got and buy a 'Y' fitting (the ones for Oxygen will work fine) and 2 flowmeters. If you search my posts, you will find a photo of mine in a recent thread.Last edited by Baila La Pinza; 03-23-2011 at 07:03 AM.
Reply:Thanks for the reply!I have been practicing different types of endings to get a clean weld made. Along with all of the other suggestions, I feel very strongly that my welds have improved!The biggest thing is slowing down, getting setup properly with enough points if contact and ensuring proper gas coverage.Seven seconds post-flow will not get you pretty stainless welds. I weld my fair share of x-ray stainless boiler tubing so it's easy at work to turn that post-flow all the way up so you can keep it all nice and pretty. Everything I'm saying may have already been covered as I haven't taken the time to read all the replys but you must keep your filler wire under constant argon coverage while welding and the filler is molten. If you pull a hot[molten] filler wire out of your argon coverage you have just contamenated your pretty weld. Where abouts are you located ? Not listed in your profile.One more thing your filler is to big imo, Try 1/16" , I keep some .045 around for small stuff as well.
Reply:What caught my eye when I read your post was the use of 309 AND  no gas lens....I have had problems getting "Cosmetic "  welds with 309 stainless parent metal....Never really used any 309 filler and don't know why you selected it?  I have found that 308L works pretty good for most applications short of FOOD related applications where 316L would be my choice......Try a gas lens, smaller filler (.035)  and better fit up..........  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Good Lord!!All those holes are trouble..First pic in this thread is very obvious and now that you have more practice via the second set of pics the holes are still there..Not very good.I would not even know where to begin if I had to fix that mess..You need to fix all that.It will never last if you dont get it right.Grind off what you can smooth and try again..You'll be glad you did......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 B_CNever really used any 309 filler and don't know why you selected it?  .
Reply:Hey guys, he said that he wasn't using a backside purge. Forget about it.  That manifold is toast.Two turn tables and a microphone.
Reply:Originally Posted by PangeaHey guys, he said that he wasn't using a backside purge. Forget about it.  That manifold is toast.
Reply:Originally Posted by B_CWhat caught my eye when I read your post was the use of 309 AND  no gas lens....I have had problems getting "Cosmetic "  welds with 309 stainless parent metal....Never really used any 309 filler and don't know why you selected it?  I have found that 308L works pretty good for most applications short of FOOD related applications where 316L would be my choice......Try a gas lens, smaller filler (.035)  and better fit up..........
Reply:I used 309 at the flange (mild) to the stainless pipe. I used 308 on all of the stainless pipe. Zap, the holes you are referring to are the creaters from stopping?I just this week With the help of the forum found out how to slow the heat down to prevent this. I will be getting a gas lense, but I didn't know what torch I had when I went to get one.   (embarrassing!)
Reply:I  have had problems welding some parts that were supposed to be 304 but got some 303 mixed in with the material being machined......The 304 parts turned out really nice but then I would grab a part made from the 303 and it didn't weld the same...Everything turned out OK but I did notice a huge difference cosmetic wise....I thought it was 309 but it was 303......It sucks getting old .....Last edited by B_C; 03-24-2011 at 01:32 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Originally Posted by shlammedNot stainless, but this is a practice for consistency and cleanliness to help my general skill.  T joint with mild. 1/8 mild, 110a plus pedal, 3/32 filler. Not my welding table, this was in my class. I can do this on mild all day now, which is good as king as it's a solid weld.
Reply:Being a gear head I think that manifold looks fine, bolt that baby on a run it.....It doesn't have to be a "SHOW CAR" to work.....If it cracks fix it.....that's what WELDORS do.....  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:any sugaring that is inside the pipe can break off when the manifold is run & it reaches temps hot enough to glow which it will if you run it to potential... even if the shrapnel isn't large enough to toast the turbo impeller immediately, it can still be enough to cause the impeller to be less than perfectly balanced, which can take out the bearing eventually anyway seeing as how the turbo can see in excess of 70-80k rpms in use... worry more about what the inside looks like if you want to not ruin a turbo...miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:I am about to start another manifold project to keep on developing skill (and i can sell it back to cover my material costs).  I will keep your comments in mind this time around guys.I will also be asking questions along the way.
Reply:The issue with stainless is chromium and the management of that.Exposed to carbon, or too much CO2 (like from air) when its molten and the chromium will just attach to the carbon.  End result: chromium carbide precipitation. That is what sugering is.BTW, the chromium get sucked out of the metal like someone put an absorbent paper towel behind the weld.  That's why its gray on the front side.Bottom line, machine with high carbon steel, or even scratching or scraping with a tool that has touched high carbon steel and you run the risk of pulling out the chromium which is an invitation to rust.I use a 3/8 aluminum plate  2'x 4' that was a drop from another customer. As for back purge, if you can't afford the dual regulator (or another bottle and normal regulator) Solar flux is almost a must (and its like $50 a can!).  Solar Flux gives the carbon something else to work on vs. chromium.If you do autogenious welding, and really watch the penetration, you can get away with good looking welds that don't have too much precipitation on the back side.  The moment you get a full penetration weld you will not only have chromium carbide precipitation on the back side, but the front side will turn ugly gray.  If you do this technique, you can come back with a second pass with filler to get the thickness.  I've never done that for a turbo housing so I don't know about ultimate strength.  The weld joint might end up being the weak point and the spot were cracking starts.As for filler, 309 is higher in nickle and that seems to help dissimilar metals.   The L just means lower carbon (remember the dreaded chromium carbide).  308 is more common for 304 stainless.  But then again, lots of turbo manifolds are made from 321 (which uses 347 filler.... and is also less susceptible to chromium carbide precipitation )Now if you find a cheap place for 321 tubing, let me know.  Everyplace I look (small volume) they charge 2x what they charge for 304 AND they are charging 2x for what others want for 304 - so effectively 4x as expensive as what I can do with 304.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Welded up this intake pipe for my civic for some practice...Setup was a 1 1/8" CK gas-saver lense @ 20cfm, 55amps on machine with foot control @ ~70%, 12 seconds postflow and minimal 0.035" 308 filler.Im still getting some discoloration in the welds and would like to get rid of it...This was wiped down with acetone and a light pass of scotchbrite pad post welding.  Material is 3a finish 304SS.
Reply:When doing manifolds or piping for that matter, fit-up means everything. You will definitely see a better fit-up in the end result.
Reply:Thanks.  The two visible bands were IMO very good fitup. And the last was satisfactory but there was probably a 0.03" gap in some places. I'm not sure that it is 100% of the problem in this case.
Reply:IF you cannot afford purge equipment you may research "Solar Flux" as an option
Reply:Very bad shielding, wrong torch angle too much heat and who knows what kind of contamination, work on something thats scrap ,clean, clean and more cleaning. That is a lot of wasted money for something that is only good for scrap. Take the time and do a lot more practicing.wboldenLast edited by wbolden; 07-12-2011 at 10:24 AM.
Reply:so i decided to see what the deal was with discoloration beginning with sheilding...so i cranked the crap out of my cheap guage type regulator to 30cfm with my CK pyrex lar1 1/4" gas saver lense and got this:Was welded autogenos fashion at 65 amps, with my pulser maxed on my tig 185 (20ppm).Weld was purged as this is 304SS  (pipe is 3a finish, flange was machined finish)Is this seen as an improvement?
Reply:Originally Posted by shlammedIs this seen as an improvement?
Reply:sorry, i had the post flow at ~10 seconds.... the point where the material welding and the tungsten would be cooled down.The arc length shorter... is this noticed by the wide blue band on the weld?  would this obstruct the structure of the weld such that it might crack?
Reply:mm vband flange
Reply:Originally Posted by con_fuse9The issue with stainless is chromium and the management of that.Exposed to carbon, or too much CO2 (like from air) when its molten and the chromium will just attach to the carbon.  End result: chromium carbide precipitation. That is what sugering is.BTW, the chromium get sucked out of the metal like someone put an absorbent paper towel behind the weld.  That's why its gray on the front side....If you do autogenious welding, and really watch the penetration, you can get away with good looking welds that don't have too much precipitation on the back side.  The moment you get a full penetration weld you will not only have chromium carbide precipitation on the back side, but the front side will turn ugly gray.  If you do this technique, you can come back with a second pass with filler to get the thickness.
Reply:Originally Posted by shlammedsorry, i had the post flow at ~10 seconds.... the point where the material welding and the tungsten would be cooled down.The arc length shorter... is this noticed by the wide blue band on the weld?  would this obstruct the structure of the weld such that it might crack?