Gas Mixer?

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Does anyone have experience with Thermco or any other gas mixer?  I am having a REAL problem getting the mixed gas I need over here, all I can get is 100% AR, 100% CO2, or 80-20 mixed, I have one company that says they can "import" 97-3, from the UK, but it's 700 dollars a cylinder.  I will be welding a BUNCH of chromium carbide and would like to use 97-3 cause I need to use stainless wire.  Any suggestions?---Thanks--Matt6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:Espat,I have and use both the Thermco (Ar/CO2) mixer and the Smith mixers.If you could be a little more specific about your needs, I may be of some assistance.Are you trying to weld SS with short arc?Are you welding SS with spray/pulsed spray?When you refer to the desired mix as 97/3 are you referring to 3% O2 or CO2?The Thermco Ar/CO2 mixer is better suited for "in shop" use as it includes it's own mixing tank.  Looking at the machine internally, the Thermco would appear to be "more sophisticated" than the Smith, but at the cost of less portability.The Smith mixers are very compact and include their own flowmeters, whereas the Thermco requires a separate flowmeter. Attached ImagesSyncro 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:What i will have is 2 flat joints 190" long, 3/4" deep and about 1/2 to 3/4" wide, and 2 vertical joints the same but only about 48" long------I have 35 of these "projects" to do.  The material is SA1750CR overlay on mild steel  (3/8" on 3/8"), welded to A514.  I need to weld the sub strat to the A514, then fill the joint and hardface over the top.  Will use spray for the flats and short circuit for the verticals.  I can use E70 to weld the mild to the A514 but prefer not to due to contamination issues if the chrome is hit at all.  Do not have pulse capabilities.  Will be using 307 wire .035"---It's what I have.  Similar to the picture, but a different layout, different configuration of bed, same concept.--Matt Attached Images6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:i use the smith mixer at work for Ar He just like the one SDIII postedMiller Xmt 350Lincoln Ln-25Ahp 200xSmith Gas Mixer AR/HTig is my Kung FuThrowing down dimes and weaving aboutInstagram http://instagram.com/[email protected]
Reply:Expat,I hope I'm understanding your situation correctly.  I'm going to make several comments/suggestions, none of which are intended to be negative.I know of no gas mix for SS that works equally well with spray and short arc.Looking at your equipment, I see you have several XMT 350's and feeders.  Have you considered picking up an Optima Pulser (for the XMT's) and pulse welding the horizontals and verticals.  If you went this way, a 98%Argon/2%O2 mix would work fine for you.  You didn't mention O2 as being available, but if you're using OA for cutting, I'm sure you can get O2.  If you went in this direction, I would recommend the Smith (299-011-1B) mixer.While I don't use it (do mostly marine and tri mix has worked well for me) Ed Craig has recommended a 98%Ar/2%CO2 mix for short arc welding of Stainless Steel.  It may work but I've never used it so I can't recommend it.  The work that I do just isn't worth taking a chance on a rather unproven gas mix.  If you decide to try the Ar/CO2 mix for your short arc welding of SS, then I'd recommend the Smith (299-006-1B) mixer.The Thermco 8500 is a great Ar/CO2 mixer (very accurate), but due to the built in tank and general configuration, it's better suited to a "fixed station" application.  Also, with the built in storage tank, you lose a little more gas in purging when you change from one mix to another.  This is why, for your application, I would recommend the Smith mixers.It really comes down to economics.  You could buy one Smith mixer (299-011-1B) which retails for about $2,500 and an Optima Pulser (retail about $1,100) and do the whole job with spray/pulsed spray or...You could buy one Smith mixer for the spray, and a different mixer for the short arc.  In this case no one mixer is going to be able to mix Ar/O2 and Ar/CO2.Personally, the one mixer (299-011-1B) for Ar/O2 and an Optima Pulser (miller #043 389) is the way I'd go.The Smith mixers and the Optima pulsers do come up on e-bay at considerably reduced prices (that's where I acquired mine) but, like everything, they never seem to be there when you need them.  That's why I listed list prices.I suspect if you did this job with pulsed spray, you'd never want to do it any other way.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:The location prohibits me from using the 350's on these jobs---no power, so I will be using one of my Pro 300's with an A-22 feeder so I can mount the gun on a track burner car and pull the trigger and not have to hold the trigger, once I get everything running smoothly, I will probably set up 2 of them to run simultaneously---Time is money.It was Ed Craig that recommended to me to use 97AR-3CO2--He says, in my particular application this would be the best gas for MIG welding stainless using SCT, spray and pulsed applications--I also really like 97-98 AR and 2-3 CO2 for bore welding, just can't get it here., hence the questions about the mixers.  I have received quotes on the Smith mixers already and like what I see,  for the price of 2 and a half cylinders I can buy the mixer, seems like a no brainer to me.How is the accuracy of the mix when using the Smith mixers, or what is your "personal" opinion of them as a user of them?--Thanks, Matt6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:Expat,I think you'll be quite satisfied with the "accuracy" of the Smith mixers.When I first got mine, my brother in law (retired from the local natural gas company) brought one of their gas analizers (probably a 50K piece of equipment) by the shop and tested the mixers.  Like I said, they proved to be very accurate.Sounds like you know which way you want to go, but doesn't that Pro 300 have Single Phase AC output of 10,000watts continuous?Good Luck.PS.  Remember that for each mixer setup, you're going to also need an inert gas regulator and a CO2 regulator (not flowmeters).  The gas is delivered to the mixer at 100 PSI.  The mixer has it's own flowmeter.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:So far, I think I am going to order 2 of the 299-006-1B mixers, 2 of the 099-011-1B mixers and 20 of the 3291 filters--(what kind of life do you get out of the filters?), and half a dozen of the Series 30 inlet regulators.  Is there anything else you would recommend?  any spare parts needed?--Matt6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers
Reply:Expat,I'd split the regulator order (3 Argon Regulators/3 CO2 Regulators).  The fittings (as I'm sure you're aware) are different.  With the low flow rate of the CO2 in the mix, you should not have a problem with the CO2 regulators freezing.  For those applications where a high CO2 flowrate is required, Smith makes a 2 Stage regulator that handles the freezing better.  Not required here.Can't really think of any additional "spare parts" that you'll be needing.  The Smith mixers are pretty straightforward and if you put clean gas thru them, I don't think you'll have any problems in the forseeable future.I fully understand that your objective is to "get er done" but I'd still encourage you to look into the Optima pulser for one of those XMT 350's.  Pulsed spray is the cat's meow for out of position work.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:SundownIII---Thanks.  The fittings are a whole nuther ballgame over here.  The 80 AR 20 CO2 gas that i can get here uses a 540 fitting, I don't know for sure what the pure AR uses, but should get one tomorrow to take a look at.  The CO2 uses some kind of funky, can't find anything like it fitting so I'm trying to do a little cross referencing.  I found a real nice selection of adaptors in McMasters and may have to go that route---no such thing as standard CGA stuff here, very frustrating.  I will look into the pulser, I am kind of "old school", but i will take a look at it.--Matt6 Miller Big Blue 600 Air Paks2 Miller 400D6 Lincoln LN-25's4 Miller Xtreme 12VS2 Miller Dimension 812 4 Climax BW-3000Z bore welders Hypertherm 65 and 85Bug-O Track BugPair of Welpers