Argon gauges vs CO2gauges???

[yeruncle]

I just noticed that Miller catolog states that the Millermatic 251 comes with "ARGON MIX regulator/flow gauge". It also lists a CO2 regulator/ flow gauge in the list of OPTIONAL accessories!!!!!! WHAT GIVES??????????
Are you telling me that I'd have to go out and buy an ADDITIONAL regulator for a BRAND NEW welder because I generally run straight CO2?
It seems that most migs come (as they should) with regulators that are compatible with both CO2 and Argon blends!!!!!
Does anyone know for sure if this is just hype? I don't recall ever seeing "ARGON ONLY" stamped on anyone's gauges. What could possibly be the difference?
It seems this MM 251 I'm in process of buying is becoming less and less of a bargain the more I re-check it!!
Any help appreciated, thanks!

[lramberson]

threads to fit the cylinder are different

[hankj]

Unc,

Yeah, it's true. Miller does not recommend running 100% CO2 through a mixed-gas designed flowmeter/guage due to the possibility of freeze-up and subsequent diaphram damage.

That said, I used my MM135 on 100% CO2 with the Smith mixed-gas flowguage that came with it for almost 2 years now with no adverse results. The flowguage DOES sweat when I get into running longer actual arc-on beads, like weave fillets, but it has never frozen. If you search on this subject, you'll find a lot of other guys who do the same, and a few of them weld far more than I do.

Hank

[ASKANDY]

yeruncle,

It's no hype. There are different threads on the regulators. They do make an adapter to go from the Ar reg to a CO2 bottle. But like the warning says, it could freeze up. Run your flow rates as low as you can to prevent this.

Have fun!

Andy

[walker]

Just to add an opinion to the freezing regulator issue, I deal with this on a regular basis. I use various regulators to cut 3600 psi natural gas down to as little as 30 psi. I forget the exact temperature/ pressures but the temperature drop about one degree for every 10 pounds cut. I have literally frozen an iceberg around regulators, with high pressure cuts, with no ill operational effect to the regulator. They still flow and lock up just fine, UNLESS there is any moisture in the gas. Then it starts to restrict the flow of gas until it thaws out. Your mileage may vary.

[drscotch]

The gases haved different densities so the flow readings will be off. The only problem is you won't know exactly what rate you're gas is flowing. Probably not a big deal for most. I've seen the CO2 adapters attached to many Ar/CO2 gauges and they seem to work fine.

[Mike W]

I have older Victor and Harris flowmeters. They both have scales for CO2 and argon/CO2.

[hankj]

Do they also have a "For argon use .032 orifice" notation on the face? Mine do. I have an old Victor with both an argon and CO2 scale, and they are not identical. I don't know for sure, but it seems that unless the correct metering orifice is installed, drscotch's post makes sense.

Hank

[Mike W]

To me orifice means flow guage. I am talking about the floating ball type.

[ASKANDY]

You all have to remember, we are talking about an inexpensive gauge with a cheaper diaphram and internals than a nicer gauge. This is the reason for the warning. I'm sure there are lots of gauges out there that do just fine in a multi gas environment. Just keep in mind that we put that warning on there 'cause we saw an issue, not 'cause we want to sell everyone a Co2 regulator.

Andy