I'm not certain as to what that will cause using the CO2 that you described, because I've not tried it. We also use 100% CO2 with our FCAW machines.
But the problem I would have to get around using it here in our shop would be conforming to AWS D1.1:2004 Paragraph 5.3.1.3 which states that ..."the gas or gas mixture used for shielding "
shall be" of a welding grade and have a dew point of -40F or lower". We have to submit certs of conformance on our wire and gas. So we need the documentation to support that the gas is of a welding grade and has a dew point of -40F or lower.
Maybe other forum users have used it on non-coded work and someone can attest to welding with the grade used in the fountain drinks.
John Wright