[rahtreelimbs]

When using helium with argon for tig welding you need a Y valve with adjustment knobs. It is my understanding that you use roughly 75% argon and 25% helium. In order to get the proper balance do you use 2 gauges and set CFH accordingly to get the proper mix?

[cj737]

You can use a Y fitting. 2 flow gauges are needed if you use 2 tanks. You can do an approximate mix of any ratio you desire. You can also have your local gas supplier provide a premixed tank of 10, 25, or even 50% Helium. I've opted for this approach and use a 25% mix

[rahtreelimbs]

I take it that a bottle used for argon can be filled with helium with no problem?

[entity-unknown]

It's an exchange program, you do not get your filled. Hopefully you didn't go any custom graphics or "cool" stickers on yours before you swap it out

[sedanman]

It's an exchange program, you do not get your filled. Hopefully you didn't go any custom graphics or "cool" stickers on yours before you swap it out

My supplier fills "your" tank if you own it. If it's leased from him, it's an exchange.

[rahtreelimbs]

Say you have your argon at 20 CFH......would setting your helium at 5 CFH give you 25%?

[Poland308]

Yes. The problem comes with trying to set your helium regulator that low.

[LtBadd]

Say you have your argon at 20 CFH......would setting your helium at 5 CFH give you 25%?

Of course you need to be using a flowmeter that has a helium scale for proper adjustment

[cj737]

Say you have your argon at 20 CFH......would setting your helium at 5 CFH give you 25%?

No, that gives you 20% (20cfh Argon, 5cfh Helium = 25cfh). 15cfh or Argon and 5 cfh gives you a 25% Helium ratio (5 cfh of the total flow).

[rahtreelimbs]

Do I need check valves for this helium mix setup? If so....where can I get these?

[cj737]

Your regulator should have one installed in it. If you use a Y connection, it too may well have one depending upon brand and model you get.

[Oscar]

My question is exactly what regulator are you planning to use on the helium tank?

[cj737]

My question is exactly what regulator are you planning to use on the helium tank?

This is the gauge I use with a pre-mixed tank, but it will work perfectly well on a pure Helium tank also

https://www.weldingsuppliesfromioc.com/ ... gJWavD_BwE

[Oscar]

That gauge is configured for output PSI, not CFM. If using CFM as the sole indicator, wouldn't he need one configured for CFM, so that he may dial in his desired mix percentage?

[cj737]

That gauge is configured for output PSI, not CFM. If using CFM as the sole indicator, wouldn't he need one configured for CFM, so that he may dial in his desired mix percentage?

Correct. There's 2 versions of that gauge, one is PSI the other is CFM. Both support Helium (and I do use the CFM models).

[rahtreelimbs]

Found this thru a Google search. Does this mean that since Argon and Helium are very close in numbers a flowmeter for Argon would work for Helium?

[Poland308]

Yes.

[Oscar]

That gauge is configured for output PSI, not CFM. If using CFM as the sole indicator, wouldn't he need one configured for CFM, so that he may dial in his desired mix percentage?

Correct. There's 2 versions of that gauge, one is PSI the other is CFM. Both support Helium (and I do use the CFM models).

Ah I see, I was wondering what was a good regulator for Helium. Thanks.

[Oscar]

Found this thru a Google search. Does this mean that since Argon and Helium are very close in numbers a flowmeter for Argon would work for Helium?

I would venture to say that is incorrect, in general. That might be specific for that Dartmouth RTA thing, but look at this Miller flowmeter. Not that 10CFM of argon (well the ball location that is), is about ~23 CFM of Helium. Now I see why people, including Jody, say you just barely have to crack it open and float the ball above it's seat; it's a heck of a lot of flow, probably due to density differences.

[kiwi2wheels]

Found this thru a Google search. Does this mean that since Argon and Helium are very close in numbers a flowmeter for Argon would work for Helium?

I would venture to say that is incorrect, in general. That might be specific for that Dartmouth RTA thing, but look at this Miller flowmeter. Not that 10CFM of argon (well the ball location that is), is about ~23 CFM of Helium. Now I see why people, including Jody, say you just barely have to crack it open and float the ball above it's seat; it's a heck of a lot of flow, probably due to density differences.

You're right. http://mpbflowmeters.com/downloads/MPB_ ... rsions.pdf

Which gives a 3.19 factor when using an argon flowmeter with 100% helium ( Ar 1.18 / He 0.37 ) which is close to what a welding engineer suggested ( 3 to 3.5 ) we use while waiting for a helium flowmeter.

[rahtreelimbs]

Can you use a TEE fitting to introduce the helium?

[Oscar]

Many people do that.

[pgk]

I had a weak moment and just bought a mixer.