Which Gas for Stainless Steel, StainMix 3 or Stargon SS

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I am mig welding a Stainless Steel smoker out of some 18ga. stainless steel,  I just ran out of my tri mix gas consisting of 90% He  7.5% Ar  2.5% Co2 and need to get some more shielding gas.  I don't want to spend another $85 for a 125 CF bottle of the Helium tri mix (Air gas) so wanted to know which gas would be a good substitute:  Airgas Gold Gas Stainmix 3 which consists of 35% helium, 63% Argon, 2.5% Co2 or Praxair Stargon SS which consists of >90% Argon, " means less than....so it is less than 90% Ar the stargon ss % came from praxair's web site that I copied http://www.praxair.com/praxair.nsf/2...5!OpenDocument and the Stainmix should be 2% not 2.5%.Last edited by hotrod123; 06-25-2012 at 02:06 PM.
Reply:The airgas mix with 35 He/2.5 CO2/Balance Argon will work, but the puddle may be sluggish.  The praxair mix with 10% CO2 is a bad choice, if you care about yor SS rusting.  Your original mix with high He is the best choice.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Thanks A Dab will do.  I think I will go with the Air Gas Stainmix.  Funny thing I just went to an independent LWS and they were telling me go with 100% argon cause I'm only welding .18ga SS.  I don't think they gave me good advice based on my welders transfer mode.
Reply:How about using Argon with 2% Co2?  I think I read it from ED CRAIG's. www.weldreality.com.
Reply:Never welded stainless with 100% Argon.  I'd think the arc stability would be terrible, and the puddle would be almost impossible to control as a result.98/2 Ar/CO2 works for SS in spray transfer.  So does 98/2 Ar/O2.  But the OP is welding on 18 gauge stainless.  The high heat input from spray transfer would warp that relatively thin sheet he's using.   The Helium/Argon mixes are better.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Ed Craig has been proponent for 98%Ar/2%CO2 for short arc welding for some time.Personally, I've never tried the mix (although I do mix my own gas).Always used the theory that if it isn't broken (tri-mix), don't change it.When you factor in the components of a SS build (base material, fab time, etc) the cost of the gas becomes a small factor.I don't do that much SS short arc mig (mostly tig), but I keep a 330 of tri-mix on hand for those jobs.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:OK, I just called Praxair and Airgas and an independent LWS and none of them carry C2  98%Ar 2%Co2.    Airgas does carry a C3 of 97% & 3%..... I think is close enough to 2% at least as close as I can get here.  I am using a fabricator 181i.  Since it only goes up to 180 amps I am most likely only going to be able to transfer with a short arc and not able to spray so I'm hoping the heat input from short arc transfer will not warp the .18ga SS sheet.
Reply:Originally Posted by hotrod123OK, I just called Praxair and Airgas and an independent LWS and none of them carry C2  98%Ar 2%Co2.    Airgas does carry a C3 of 97% & 3%..... I think is close enough to 2% at least as close as I can get here.  I am using a fabricator 181i.  Since it only goes up to 180 amps I am most likely only going to be able to transfer with a short arc and not able to spray so I'm hoping the heat input from short arc transfer will not warp the .18ga SS sheet.
Reply:Dave when you say very splattery using a short arc transfer with 97%/3% would it be overly excessive?  The build is a smoker out of some beer kegs  and my welding ability is far from professional so some splatter won't bother me, but I don't want it to look like I stick welded it with splatter all around the welds.  I think I could also crank my unit up to 180 amps and try to spray it but then I realize I will have to be concerned with the heat.Thanks,
Reply:Originally Posted by hotrod123.....some splatter won't bother me, but I don't want it to look like I stick welded it with splatter all around the welds....
Reply:This is irrelevant but is 75/25 a bad choice for SS 308 fluxcore dualshield?
Reply:Originally Posted by hotrod123Dave when you say very splattery using a short arc transfer with 97%/3% would it be overly excessive?  The build is a smoker out of some beer kegs  and my welding ability is far from professional so some splatter won't bother me, but I don't want it to look like I stick welded it with splatter all around the welds.  I think I could also crank my unit up to 180 amps and try to spray it but then I realize I will have to be concerned with the heat.Thanks,
Reply:Just to follow up.  I had no splatter with the short arc transfer with .030 / L308 using the 3% C02 (GG Stainmix) on 18ga SS
Reply:thanks for posting results, any pics?I'm guessing the "stainmix" is what Airgas recommended?Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:No pictures but the gas is from  Airgas.  I did email Ed Craig from Weldreality asking him about the splatter using short arc transfer.  Below is a copy of my email to him and his reply. On Jun 27, 2012, at 7:42,  hotrod123    wrote:  ">I have just have one concern.  Before I discovered your web site I was at the weldingweb.com forum, I had posted a thread this past Monday asking "Which Gas for Stainless Steel, StainMix 3 or Stargon SS"  and one of the replies was that the 2% CO2 mix is best for a mig spray transfer and not short arc because I will get a lot of splatter with the short arc.  My unit is 230 volts but only goes up to 180 amps(Thermadyne Fabricator 181i) and the stainless steel I want to weld is only 18ga thick.  Do you think I will encounter a bad splatter issue if I use a short arc transfer?  I really don't want to use a helium mix again due to cost although I think it welded nice.  Since I am a novice and my welds are far from that of a professional along with the fact that I'm building a smoker for my backyard, I am not overly concerned if I have a small amount of splatter but still want to be proud of doing the best job I can.  So I just want to check with> you before I pick up the gas that without the ability of a spray transfer I should still go with the 3%Co2.> Thank you again."Ed Replied:"With 035 wire You should short circuit around 200 inch/min (10 oclock) and 15 - 16 volt"I was using .030 308L wire and not .035 as he suggested and played around with my settings before I was satisfied with the sound and quality of the welds. I don't remember the settings I used but I forgot that he suggested the 200 ipm  and 15 16 volt settings and it still came out fine with NO splatter.   I hope that helps anyone.Last edited by hotrod123; 07-17-2012 at 06:31 PM.
Reply:Originally Posted by hotrod123I am mig welding a Stainless Steel smoker out of some 18ga. stainless steel,  I just ran out of my tri mix gas consisting of 90% He  7.5% Ar  2.5% Co2 and need to get some more shielding gas.  I don't want to spend another $85 for a 125 CF bottle of the Helium tri mix (Air gas) so wanted to know which gas would be a good substitute:  Airgas Gold Gas Stainmix 3 which consists of 35% helium, 63% Argon, 2.5% Co2 or Praxair Stargon SS which consists of >90% Argon, <10% Co2 <10% Nitrogen.Thanks
Reply:I asked a Praxair rep about it at Fabtech last fall and he was cagey about the exact composition. I opined that it would be a hard sell to anyone working to a WPS or any code when the composition is a vague "trade secret". Argon/CO2 mixes with added Nitrogen are commonly used for welding duplex SS, so the idea, at least, is valid.I have always used C3 (aka Stainmix Gold) for SS MIG, and while it's best with spray or pulse, it's not too bad with short-arc either.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:I wanted to get 2% C02 but Airgas had Stainmix which their website says is 97% AR and 3% CO2.  I wanted to get 2% but from my research 5% - 2% is fine.  Like I said the 3% had no splatter.  I will post some photos shortly.  My camera battery is dead and is charging.  But I warn you that my welding doesn't look nice.
Reply:Ok after looking at my photos I do have some splatter, but minimal for me and with the cost difference of using helium, I can live with the results for hobby welding.  These beads were practice welds while trying to get the settings right,  which might have something to do with it how they look but I don't really know.  I'm not sure if I ever got my machine  dialed it in but I'm teaching myself so I blame it on the instructor.  I know my welding skills are very bad.
Reply:Thanks Hotrod,after reading your thread I went to Airgas to get some "stainmix".The first salesman didn't know it existed....The second recommended a tri-mix: 90%He, 2.5% Ar, 2.5% CO2; which I got.  Only arc welded stainless before, so anxious to try mig.What regulator did you use?Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:The helium tri mix is very nice and smooth but pricey.  When I went to Airgas they were clueless as well.  Probably because they do have a lot of different gases and or lack of experience on the sales peoples part.  Anyway you'll like the tri mix.Last edited by hotrod123; 07-18-2012 at 11:52 PM.
Reply:Thanks for the info.  Cool thread.  HotRod, did your real welds look as cold as the practice welds you are posting?TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:Originally Posted by Drf255HotRod, did your real welds look as cold as the practice welds you are posting?The voltage does sound a bit low to me, but too much voltage can make it difficult to weld vertical. You may find C3 harder to "dial in" than tri-mix but its not that hard, and you're not paying the Helium Tax!JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Originally Posted by dubl_tThanks Hotrod,after reading your thread I went to Airgas to get some "stainmix".The first salesman didn't know it existed....The second recommended a tri-mix: 90%He, 2.5% Ar, 2.5% CO2; which I got.  Only arc welded stainless before, so anxious to try mig.What regulator did you use?
Reply:Josh,Frankly, I don't understand your post at all.For years, the industry strandard for short arc mig welding of SS has been a tri-mix (consisting of 90%He/7.5%Argon/2.5%CO2).  Are you suggesting that everyone (including Miller in their GMAW Handbook) doesn't know what they're talking about?A mix of 98% Argon, 2% O2 is a widely accepted mix for spray arc welding of SS, but not applicable here due to the machine the OP's using as well as the material he's welding.I have the capability to EASILY mix 98%Argon/2%CO2 using either my Thermco or Smith mixers, but I still choose to use the tri-mix for short arc welding.  This mix has proven itself to produce quality welds with excellent resistance to rusting.I have had to "redo/repair" too many marine railings that were mig welded with an excess of CO2 in the mix, to "take a chance" on my gas mix.My Thermco mixer stays hooked up to a 330 of Argon and a 50# CO2 cylinder.  Mixing Argon/CO2 (from 1% CO2 to 25+%CO2 is as easy as turning a knob).  Even with that capabiliy present, I still choose to use the "approved/proven" tri mix.  Maybe some day, especially considering the rising cost of helium, I'll try the 98%Argon/2%CO2 on a scrap project and just let it weather in the salt environment to see how rust resistant it really is long term.  Haven't had the need to go that route yet.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.