> From: George Booth <booth at hpmtlgb1_lvld.hp.com>

> The best is a two-stage regulator designed for use on welding gas
> cylinders.  This reduces the 950 psi tank pressure to 10-20 psi.  You
> can get a cheap fixed-pressure regulator with no gauges for about $45
> from places that have beer brewing supplies.  The lowest cost is a
> Flow Regulated Orifice Gauge, FROG, and puts out a constant pressure
> (22 psi or so).  These are available from welding shops and are cheap
> but there are no gauges so you don't know when the bottle is about
> empty.  Without gauges, you'll just be surprised some day when you
> check the controller and find your pH is 8.2.

George, the FROG is a little better than that, because it does have a
little pop-out thing that tells when the tank is running low.  The label
says "10 minutes left when it pops in".  But this is for welders who are
not running it through a needle valve, so I'd guess you probably have a
week before you have to actually replace the tank. 

This is, of course, much much better than the single-gauge regulator I
bought for $50 which gives me NO indication at all, and 6 months later
when I tried to take it back to have an inlet gauge added they told me the
manufacturer welds that port shut.  D'oh! 

A real bad thing about the tank running out is that water can be pushed 
back through the CO2 line and into the needle valve & regulator.  Not a 
good scene.

   - Erik

Erik D. Olson                		E-mail-o-meter:
olson at phys_washington.edu             	it's back up!