Mixing chamber

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Looking to purchase a mixing devise for Helium and Argon......With Helium prices like they are I want to mix my own gas........Anyone have something they can recommend? I used to use a simple Y fitting in the past but want a more accurate method .... Last edited by B_C; 03-11-2013 at 08:03 PM.  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:I was pretty content with the mixed gasses until the price went through the roof....and also I got a couple bottles that were WAAAAAAAAY off the ratio they were supposed to be........My 330 bottles of 25 /75 Argon Helium are 162.00 now  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:I've seen them at HGR for $600. Found mine on Craigslist.Dynasty 300DXSmith He/Ar gas mixerMM350PHobart Handler 120Smith LW7, MW5, AW1A
Reply:I know you have the skills to build one, finding drawings for one might be a little tougher.
Reply:Sundown III uses a Smith unit (or two).  If I recall correctly, it wasn't for the specific gasses he was mixing, but Smith gave him a correction factor to use."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:I believe the one that has been mentioned is the one I built which is way more complicated than what you need. Mine was built to allow two different outputs allowing for a trimix on the MIG side and just helium argon on the TIG side.   Here's the thread I did on it.http://weldingweb.com/vbb/showthread.php?t=41659  Anyway after living with this setup for a while now I can say that it's not perfect but it does work if care is taken. The primary difference between what I built and what Smith makes is on the input side. They have a balance regulator that keeps the pressure of the input gases at exactly the same pressure. I on the other hand have to keep a close eye on the pressures being put out by the regulators on the tanks. They do drift as the high side pressure changes. I still have a slight problem with the volume of gas in the long hoses in the reels giving a little to much sudden burst pressure at the start of a weld though not as much as I had with my old setup.   In your case of just mixing two gases for TIG it's a little simpler. It's is possible to mix with just two flow meters and a Y. I would definitely keep both flow meters the same high quality brand and putting output pressure gauges on them to keep them at the same pressure would be a good idea. Accuracy would depend on keeping those pressures the same. I would also try and keep my hose lengths and sizes down as much as possible to keep the wasted gas down. One of the problems with this setup is the fact that when the flow shuts down there's a short period of flow going into the hose as the system catches up. If one of the gases is at a higher pressure than the other then it will tend to fill the hose with more of that gas than the other throwing the mixture off. Putting the Y close to the machine and having check valves on it would go a long way to helping prevent this problem.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm