Re: [APML] Hypering psi?

["Bert Katzung" <katzung1@attbi.com>]

Hi Grant:
It may not be as bad as it sounds---could be something as simple as a piece
of grit in the o-ring groove, or just a need to tighten the tank valve in
its threads. I had a much faster "slow" leak than the one you describe on
one of my runs---I was hypering on the open reel with the cassette still
attached and lying on top of the reel just under the cover. When I took the
film out, it turned out the part of the film sticking out of the cassette
had gotten crimped between the cover and the base of the tank, preventing
the top from sealing completely. Interestingly, it didn't prevent me from
hand-pumping the initial vacuum, but it sure allowed the gas to leak out
fast. I had to refill it every 3-4 hours to keep it at 3 psi.
Good luck!
Bert
----- Original Message -----
From: "Grant" <GB1029@inter-linc.net>
To: <astro-photo@seds.org>
Sent: Sunday, July 07, 2002 12:57 AM
Subject: Re: [APML] Hypering psi?


> Thanks Bert.  This is definitely bad news.  If in fact it is a leak,
> it must be either the o-ring or the chamber valve.  Neither of
> which would seem to be an easy fix!  I guess we'll see...
> In the meantime, I went ahead and
> gassed out again and refilled the tank to about 6psi.
> Hopefully, positive pressure will hold for the remainder of the process.
>
> Grant
>
> At 11:37 PM 7/6/02 -0700, you wrote:
> >Hi Grant:
> >I don't think it's normal. There's a slow leak somewhere. After you take
the
> >film out, try pressurizing it with nothing inside and use the soapy water
on
> >the outside and looking for bubbles technique. Probably around one of the
> >fittings or valves but might be a micro-crack in the O-ring.
> >Bert
>
>
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