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Re: CO2 regulator problem -- How to cut it and How to roll a joint.

Eric Wahlig offered some good tips on CO2 regulator use -- of course,
that won't stop me from adding some comments of my own ;-) :

"> The length of line shouldn't make a difference in the performance of
> a 
> needle valve.Well, it can have this effect, adjustments to the valve
don't immediately show up in the bubble counter.  Why?  Because the
length of tubing acts like a momentary pressure buffer; the longer the
tube the greater the effect.  Some well pumps actually have extra
volumes built into them just to keep momentary changes in pressure from
affecting the outlet flow.

> . . .I am suspecting that debris or dirt or water or something
> has 
> gotten into the system and is causing problems. Here are a few
> guidelines to 
> help prevent line contamination by foreign matter:
>   1.) Always "crack" the valve on a gas cylinder before attaching the
> regulator. This brief blast of gas blows out any dust or dirt that
> may be in 
> the tank valve.

Good advice but be ready for the auditory shock.  The blast can be high
pitched an in excess of 80 decibels.  Also be careful what the tank
valve opening is pointed towards.  A blast is a blast and who wants to
re-collate that dissertation?  Also, you don't want any dust or debris
to be blown right into your eye.

>   2.) I am very skeptical of check valves to prevent water from
> entering the 
> expensive CO2 equipment and any good ones that I think might be worth
> using 
> are rather expensive. 

I think most check valves work pretty good and even the good ones can
let a couple drops get by.  But you'd need an awful short tube for a
couple of drops to make it make to the CO2 equipment.  Put the check
valve as far drown the line, as close the the water source, as

> A positive way to prevent water from entering
> your CO2 
> equipment is to keep the regulator/valve assembly above the level of
> the 
> tank water. I admit this can be difficult or looks weird. In fact, it
> may be 
> dangerous if you don't secure the cylinder against falling over but I
> guarantee you won't get water in your CO2 system where it shouldn't
> be.

Not only does this impose the need to wear a hard hat (just kidding)
but you can still get water in the tank.  Pressure differentials can
cause a relative vacuum to suck water in to the CO2 tank.  Rare event,
requires a dead empty CO2 tank, sharp drop in ambient temp, etc.

>   3.) If you are using teflon tape to seal the joints be very
> meticulous 
> about how this is applied. The tape should be trimmed with scissors
> to a 
> width that will allow the first thread to be bare. 

No need to cut the tape.  Just stay away from the first *few* threads
when you wind on the tape.  If the excess bothers your, you can trim it
afterwards either with a cutting edge or, usually, just by pulling it
off.  The portion of tape that's doing any good can't be pulled out;
it's tight in the joint.

> Often it can be
> peeled or 
> split lengthwise into narrower widths. Keep the tape well away from
> the end 
> of the fitting and wrap it exactly twice. 

The number of ideal wraps depends on the condition of the two pieces of
the joint.  You might need more wraps to get a tight fit -e for
example, if your pieces have been assembled and disassembled several
times.  Pipe threads are tapered threads.  ;-)

> Use the scissors to trim
> the 
> length. 
Or don't. Or buy narrower tape.  I never knew a fitter that cut his or
her tape and it's not really necessary and it sounds like a meticulous
pita.  The point is to keep the Teflon out of the tubing interior --
don't wind it on there and you won't have a problem.

> Wrap it clockwise around the male fitting 

Clockwise *as you face the mating end of the fitting* if you're dealing
with normal threads (righty-tighty).  If you're one of those rare folks
that cobbles together a series of adapter so that you can use an Oxygen
tank, which has "reverse" threads, then you wind the tape in the
reverse direction too.  

> to prevent it from 
> binding, or trying to unravel, when you screw the pieces together. If
> you 
> make a mistake, or unscrew a connection made with this tape, you must
> thoroughly clean any and all remains of the teflon tape from both
> male and 
> female fittings before they can be re-joined. This last point is very
> important. I clean and inspect the threads of each piece with a
> dental pick 
> under good lighting. It is amazing how a small fiber of this stuff
> (or 
> anything else) will clog your system.

When they say needle valves, they mean it.  How else could the gas-flow
reach supersonic speeds unless the opening was very very itty bitty ;-)

[No need to complain TW -- we have the archives ;-) ]

When you wind Teflon tap around a fitting, it winds more easily
depending on which way the tape is unrolling -- when you are at the top
of the fitting (the tape roll is above the fitting), is the tape coming
from the bottom or the top of the roll.

You can roll a joint like this:  Hold the tape roll above the fitting
with the tape hanging down from the side of the roll that isn't facing
you.  Let out an inch or so from the roll an lay it across the fitting
above the upper threads.  With the hand holding the fitting, put your
thumb on the tape to hold it against the pipe.  With your other hand
holding the tape roll, wind around the fitting, pulling the tape snug
as you go.  After a few turns, you can yank/snap the tape to break it
off the roll or you can cut it with the scissors in your third hand 

As Eric said, make sure none of the tape is down by mating end of the
fitting when you join the fittings.  If the tape worms down into the
joint, you're bound to have gas problems sooner or later :-|

Scott H.

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