[Shop-talk] CO2 And Argon for MIG

[Bob Nogueira]

I have a C02 tank for my MIG. I'm planning on doing some Aluminum work  so
I was checking on switching to Argon, My gas supplier says that I will need
to buy a Argon tank. He also says that a  75%  C02  25% Argon will work
better for steel than 100% C02. 
Since I have a CO2 and a Argon regulator could I hook up both bottles and
regulators ( 100% CO2 and 100% Argon) with a  " Y " joint located after the
regulator  and  use  a after tank mix?   
If so any suggestions on how to get the 25 - 75 mix ratio adjusted ? 

Bob Nogueira