More Help with Stainless Tig

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Not wanting to thread jack another thread on stainless tig I made another.I have been participating in the other threads on tig with stainless and have gotten some better results.Advice was given me on one reply to not pay attention to color at my level.Looking at my beads below, the beads I think were my best results, what should I be looking at to correct some of my issues?I only looked for color because I was under the impression that color tells if heat is correct or not.I usually get the "grey" beads with no color and a very flat no shine finish.  I mostly get my best bead results, or what I think are my best, the first two or three beads I run. Then things go down hill.The beads below were run on a stainless bar 1" by 1" thick square.  I was using 3/32" Red 2% tung, Medium gas lens #8 cup, air cooled WP17 torch, argon gas, 3/32" 308L filler and about 65 to 80 amps if I remember correctly.  No foot pedal or amperage control, HF start only.Last edited by MWalden; 08-20-2013 at 12:20 AM.
Reply:This is a more typical result.
Reply:classic example of too much heat at the part.  The beads you are making are very long and thus the whole thing heats up and the heat has no where to go to dissipate.  Compound that with the fact that SS dissipates heat very very slowly, is why the metal is oxidizing---it's too hot after the argon has dissipated.  How long is your arc length?  Chances are you're too far from the base metal---this heats up the part dramatically.    I know because I'm still combating this issue as well---getting better, but it takes time.Try doing short 3/4" to 1" long beads.  Keep your arc length very very tight.  Only use as much tilt on the torch as you have to---too much tilt is the same using too much arc length; voltage goes up and more power gets dumped into the whole piece heating it up to the point where the surrounding metal cannot wick heat away from the puddle/bead.  Run that short bead, then wick the heat out of the part before you do the next beads.  It is very easy to overheat SS because it is very very stubborn to conduct/dissipate heat---so you have to be pro-active in the artificial dissipation of the heat.  This is why some pro's use copper heat sinks when doing SS.  Also, try with 1/16" filler.  If you can get 1/16" filler to the puddle edge without it balling up, then it is generally an adequate size and needs much less amperage at the puddle to melt it without having it stick.Last edited by Oscar; 08-20-2013 at 12:34 AM. 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:Need to not "nasa" the torch at the end of the bead.  You're pulling up as you continue travel.Also, looks like you need to ease off the pedal as you get towards the end.Miller Dynasty 200DXMiller Spectrum 250DMiller Millermatic 200Bunch of old blue dinosaurs....
Reply:Need to not "nasa" the torch at the end of the bead.  You're pulling up as you continue travel.Also, looks like you need to ease off the pedal as you get towards the end.Miller Dynasty 200DXMiller Spectrum 250DMiller Millermatic 200Bunch of old blue dinosaurs....
Reply:Originally Posted by Oscarclassic example of too much heat at the part.  The beads you are making are very long and thus the whole thing heats up and the heat has no where to go to dissipate.  Compound that with the fact that SS dissipates heat very very slowly, is why the metal is oxidizing---it's too hot after the argon has dissipated.
Reply:Originally Posted by jontheturboguyNeed to not "nasa" the torch at the end of the bead.  You're pulling up as you continue travel.Also, looks like you need to ease off the pedal as you get towards the end.
Reply:Originally Posted by Oscarhe doesn't have a pedal, hence no heat modulation--or rather I should say not as much heat modulation as he could have.  As we all know, for SS heat control is critical, so no pedal is like starting out with a handicap to start out with.
Reply:Originally Posted by OscarIf you can get 1/16" filler to the puddle edge without it balling up, then it is generally an adequate size and needs much less amperage at the puddle to melt it without having it stick.
Reply:You dont need a foot pedal to tig weld stainless steel.I use scratch start and set the current on the welder then go to it. Use your arc length to make slight compensations in heat if you need it.Having your welder set too cold is just as bad as having it set too high. Too cold and you have to hold the torch too long to get the base metal fluid. That puts alot of excess heat in the HAZ (heat affected zone) and can over heat the parent metal area. If you have the machine set at just the right amount of current, the base metal goes fluid rapidly, you move quickly and add filler while producing a nice bead.Remember, stainless steel likes to oxide. You need to use a wire wheel on your grinder to remove the oxide coating from the metal before welding. Use the wire wheel to polish the weld bead after welding as well to bring out the shine in your weld.Also keep in mind if your welding an open joint, you will require a back purge or solar B flux to prevent sugaring of your weld on the back side. Stainless welds very nice with tig. Keep it simple, practice and it will all come together for you.Last edited by snoeproe; 08-20-2013 at 09:28 AM.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Are stainless tig beads also usually supposed to be narrower beads than on regular steel?
Reply:As long as you have some colour in weld you're good (if it's note some nasa or russian space program stuff). You have problems at the end, try more down slope time and let post flow do it's work, leave torch blowing argon on the weld when you stop welding . My guess is that you are too slow. Try 100-120 amps with 1/16 tungsten and 1/16 filler rod but with faster travel speed.
Reply:Originally Posted by ravseljAs long as you have some colour in weld you're good (if it's note some nasa or russian space program stuff). You have problems at the end, try more down slope time and let post flow do it's work, leave torch blowing argon on the weld when you stop welding . My guess is that you are too slow. Try 100-120 amps with 1/16 tungsten and 1/16 filler rod but with faster travel speed.
Reply:Originally Posted by snoeproeRemember, stainless steel likes to oxide. You need to use a wire wheel on your grinder to remove the oxide coating from the metal before welding. .
Reply:Originally Posted by MWaldenAre stainless tig beads also usually supposed to be narrower beads than on regular steel?
Reply:Originally Posted by OscarGood question.  I'm assuming you are meaning for a given material thickness, joint type, and amperage?
Reply:Originally Posted by Oscarcome again??
Reply:Originally Posted by snoeproeEver seen pipe welders tig weld stainless pipe?Stainless (much like aluminum) develops an oxide coating on it from the atmosphere if it sits for some time. To make a good weld, you need to remove that oxide coating with a wire wheel on your angle grinder before welding. It's standard practice when tig welding stainless pipe.
Reply:Got in another half hour or so before the thunderstorms arrived this afternoon.I am down to this last round bar of stainless and then I have no more material.I bumped the amps up to about 110 at the max.  It seemed a bit too much and I went down a few amps at a time to a low of 70amps at one point. That seemed too cold.Went back up to around 90 to 100 amps.  Seemed about right as I got an almost immediate puddle and the puddle width stayed a little wider and shinier.I tried hard to keep a tight arc length. I dipped the tungsten several times and had to resharpen each time.  I got the puddle going and tookoff and tried to keep a consistent and quick travel speed.1/16"  308L fille rod, 3/32" 2% Red tung, all metal cleaned with a stainless wire brush prior to welding.  Welds and material allowed to cool after a couple of beads before going back in.First two beads are before brushing with stainless brush.  All others are after brushing.
Reply:Originally Posted by MWaldenGot in another half hour or so before the thunderstorms arrived this afternoon.I am down to this last round bar of stainless and then I have no more material.I bumped the amps up to about 110 at the max.  It seemed a bit too much and I went down a few amps at a time to a low of 70amps at one point. That seemed too cold.Went back up to around 90 to 100 amps.  Seemed about right as I got an almost immediate puddle and the puddle width stayed a little wider and shinier.I tried hard to keep a tight arc length. I dipped the tungsten several times and had to resharpen each time.  I got the puddle going and tookoff and tried to keep a consistent and quick travel speed.1/16"  308L fille rod, 3/32" 2% Red tung, all metal cleaned with a stainless wire brush prior to welding.  Welds and material allowed to cool after a couple of beads before going back in.First two beads are before brushing with stainless brush.  All others are after
Reply:Originally Posted by dcoffmanjrStill looks to hot. I may have missed it, but what are you running for a cup, and cfh on your gas? And is that round stock our is it pipe, and what size?In any case, pick up the travel speed a bit and shoot for a shallower bead profile. Sent from my SGH-T989 using Tapatalk 2
Reply:Dont bother with super tight arc. For me a medium arc lenght works best. I weld stainless steel and titanium all with #8 cup an 8lpm (16 cfm) and all my welds are silver old gold colour. I have never used a pedal. For me fast travel speed and few more amps works best- dip move few mm and dip again (on titanium dipping 3 times per second).
Reply:Thunderstorm passed so I went back in for a few more attempts.NOTE:These two beads below are what I think is the closest I have gotten to correct.  However, these beads were done with no filler metal.  I simply got a puddle and ran a bead by washing the metal around.  So, something is going wrong as I add filler.  Not doing something correctly.These are unbrushed after weld.  Settings were 65amps, no filler, 3/32" tung, 20cfm gas flow, medium gas lens #8 cup.Last edited by MWalden; 08-20-2013 at 06:51 PM.
Reply:The pics below show a start amps of 65 and I step down to a low of 50amps.  My travel speed was still too slow on these beads.These beads are using filler wire instead of puddle washing.1/16" filler wire, gas lens with #8 cup.  Bead ran at 65amp  Bead ran at 60amp  Bead ran at 55amp  Bead ran at 50ampLast edited by MWalden; 08-20-2013 at 06:52 PM.
Reply:The pics below show those beads above compared to a 1/16" filler rod for size comparison.I'm gonna go out on a limb and say that you just dont have enough post weld argon coverage.  A 3/4" bar is quite small and is approximately like welding an outside corner joint.  The argon has no where to hang out on top of the bead (because obviously the bar is curved), so it being denser than air, it tends to just dribble down like water rolling down the bar, exposing the weld puddle that was liquefied just an instant ago to oxygen in the air.  Try this---get some heavy duty foil and fold it up a few times over, and make a V-type of dam to help trap some of the argon.  Basically, simulate an inside corner joint by using the foil as an "argon dam".  If this doesn't help after a few tries, then I take all this back.  A crude illustration of what I meanLast edited by Oscar; 08-20-2013 at 07:30 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:Originally Posted by MWaldenThunderstorm passed so I went back in for a few more attempts.NOTE:These two beads below are what I think is the closest I have gotten to correct.  However, these beads were done with no filler metal.  I simply got a puddle and ran a bead by washing the metal around.  So, something is going wrong as I add filler.  Not doing something correctly.These are unbrushed after weld.  Settings were 65amps, no filler, 3/32" tung, 20cfm gas flow, medium gas lens #8 cup.
Reply:Everyone is suggesting you're running too hot, and I agree in part. By running beads on such a small piece of stock, after a few beads, your HAZ would be really hot. Try quenching your scrap piece in water every few beads. This will keep the practice stock cooler. My approach to your practice parameters:1) I typically use a # 6 cup with a 3/32 tungsten2) when I was learning O.A. & tig welding, we puddled first. Line after line. it's analogous to practicing your handwriting. Once near perfection was achieved, we were then allowed to add filler rod.3) Try maintaining a smaller puddle, maybe 3/16 dia.Making practice more of a structured affair, rather than running random beads, will help you learn control ... which is every bit as important as color.http://www.facebook.com/LockhartMetalArthttp://www.facebook.com/pages/Grumpy...44306259043484
Reply:Originally Posted by OscarTry this---get some heavy duty foil and fold it up a few times over, and make a V-type of dam to help trap some of the argon.  Basically, simulate an inside corner joint by using the foil as an "argon dam".  If this doesn't help after a few tries, then I take all this back.
Reply:Originally Posted by dcoffmanjrBut on the flip side of that - I'm not 100% sure it's a shielding gas problem
Reply:Originally Posted by OscarI agree completely--IMO the real issue is heat control in the sense that there is no way to taper down the current as the bead is being made, especially on such a tiny part.  My suggestion is more of a brute-force approach because of the machine limitations.  Those pieces you welded up are huge and represent a much larger heat sink than his round bar, even if they are thinner---there's just more mass around the weld joint.So yea, it's not really a shielding gas problem as it is a heat problem that be cleverly pounced on by brute-force approach---get the part immersed in a lingering cloud of argon, and it has no say so in the matter and will cool down more before the argon dissipates.
Reply:Well well well.   It wasn't me, heat or shielding gas all this time.  It was the friggin metal!  I even tried the gas dam that was suggested and got the exact same result as before.  Gray weld beads no matter what heat I used.  I think that **** was some kind of tool steel.I ditched that piece of trash rod I had and got a piece of real stainless that I know is real stainless.  It was my "blade" on a press break I had built and no longer use. It is 1/4" thick flat bar.First bead was shiny.  Really shiny.  And this metal ran like a dream.  I had no issues with the metal jumping up onto my tungsten as I had with that other thing.  The puddle formed easily and was easy to manipulate and it stayed flat.I was able to keep a nice close arc length too.I used the same 65 to 80 amps of heat, 1/16" filler, 3/32" tung and the gas lens with #8 cup.  Argon flow at 25 to 30cfm.One bead in my pictures below looks kind of gray but it really isn't as gray as it appears.  It isn't as shiny as the others but its not real dull.I can work with this and can move on and improve I hope.  I will get some more real stainless soon and work on this diligently.  I will also work on more consistency in my beads.Last edited by MWalden; 08-21-2013 at 12:19 AM.
Reply:More of the same in different light and angles
Reply:Grrrr!!  Next time make **** sure it is really stainless!!!  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:Originally Posted by OscarGrrrr!!  Next time make **** sure it is really stainless!!!
Reply:Originally Posted by MWaldenCrap, does all stainless not weld the same?
Reply:Originally Posted by OscarI think you should fore-go picking up more un-identified SS at the scrap yard.  You'll save yourself years of aggravation....and you'll save us time from posting up advice that doesn't apply to your extra-terrestrial unweldable metals
Reply:lol too bad I didn't see this thread sooner. That looks like free machining steel with the way it's melting and flowing together into a blob and leaving a crater. Obviiusly not 304 or similar stainless anyway.Welding/Fab Pics: www.UtahWeld.com