Back purge is in the 10 cf range. If your using a big Furick cup, that will be in the 30-35 cf range. You really need the ability to regulate the gas flow for the purge and torch separately to get the CF right for both. Dual regulator is the only way to accomplish this, and the outputs can be shutoff to use one or the other, or both. Here is mine, the way I have it turned, the helium scale is on the front and Argon scale is on the back, so I just transferred the scale to the front with a Sharpie. I only use Argon.
