The orifice is a threaded insert that has and edge on the inside that the
second stage seat mates up with and is threaded into the tube that holds the
poppet assembly. There is a barrel o-ring on the outside diameter of it that
seals it. On an Apeks, the orifice has a hex key female end that you can
turn , on Scuba Pro it is a slot for a screw driver. Screw driver slot is
the way most regs are, but that presents a risk of scoring the walls of the
tube and making it harder for the o-ring to seal. To tune these regs, you
generally hold the purge button in , turn the orifice all the way in, and
then back it off until it will not bypass. Then , as you tighten it further
it will be harder to make it freeflow and of course, harder to breathe.

What I do is tune it with the adjustment knob halfway in such that the reg
will not freeflow when purged. This way you can both shut it down when not
in use or make it easier to breathe. You do not want a reg tuned on the
"edge" so that it violently freeflows if triggered. There is no need for
that kind of gas delivery unless you are trying to blowstart a jet engine.

Scuba Pros are a big problem in this regard as the seat will not tolerate
repeated adjustment, whereas the Apeks will let you do whatever without
wearing out. Also, the lever arm ears are captured by a plastic collar on
the Apeks so you will not get the ears to pop out of the ridges in the
poppet assembly and fail in the off position like the SP will do if you were
to both tighten the orifice and then try turning the adjustment knob all the
way in. Also, the Apeks seat will not dry out and harden up on you and fail
when you do not use the reg for a while. I have to keep my SP regs wet in a
sealed box to keep them working.

The best bet is to lower the IP to 120, maybe less for freezing weather, and
then to tune the second the way I mentioned. The other thing is to avoid
having any high performance inflators on you wings as these are both
unnecessary ( you need to anticipate buoyancy and descend properly) and they
represent a risk of freezing the first stage and or losing a bunch of gas if
they fail or fail the wings. An air balanced inflator is beyond the pale
stupid.

As always, there is a dirt simple solution to everything in this sport, and
there is never any need to convolute or sacrifice part of the system by
offsetting perceived problem with a bigger problem.


-----Original Message-----
From: ben lim [mailto:tingtong74@ya*.co*]
Sent: Saturday, January 05, 2002 9:22 AM
To: Trey
Subject: Apeks 2nd stage orifice


Hi mr irvine,
i'm sorry to trouble u again.
i tried asking around on what u actually meant by
having orifice tightened. But then none of my pals
actually knows.

i understand this might sound silly to u, but can u
kindly just provide more insight on it.

i trying to contact my locl apeks dealer , so all i
need to do is to ask him to tighen the orifice ?
nothing more spcific than that right ?

thanks
ben



--- Trey <trey@ne*.co*> wrote:
> The second stage needs to have the orifice tightened
> so that it will not
> freeflow.
>
> -----Original Message-----
> From: ben lim [mailto:tingtong74@ya*.co*]
> Sent: Wednesday, December 26, 2001 12:46 PM
> To: trey@ne*.co*
> Subject: Apeks FCD ( 2nd stage set)
>
>
> hi mr irvine,
> i was reading your post in techdiver@aquanaut.com
> about the apeks FCD.
>
>
> u gave this reply to a mr George Giovani:
> "Those things break before you get a chance to
> freeflow. I can not imagine what you guys are doing
> to
> freeze regs. They should have the IP turned down
> and the second stage set so that it will not
> freeflow.
> I have only been able to freeze a reg in the air,
> and
> that was a SP MK G250."
>
> I understand the tuning down the IP settings ,but
> what
> do u mean by " the second stage set " ?
>
> i thought all we have to do is to tune the IP of the
> 1st stage down to about 120 psi ?
>
> thanks
> ben
>
>
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