Re: [APML] Adapting Nikon F3/T for gas purge

["Steve Walters" <swalters@att.net>]

Kent,

I vaguely recall from working in an industrial lab long long ago that
nitrogen was available as either "Nitrogen" or as "Dry Nitrogen". I think
"Anhydrous Nitrogen" was the term. The difference was the H2O content.
Anhydrous (dry) was nearly pure N2 whereas regular nitrogen tanks had some
level of water moisture in the gas. I recall that we had both kinds of tanks
in this lab for different processes. I may be completely mixed up here as
this is going back some 35 years for me.

But if this is the case, I assume that we should be using the anhydrous form
of N2 for these purges although the H2O content of normal N2 may be quite
low, for all I know. But I never see this mentioned in any of the postings
regarding N2 purges.

Can someone clear this up for me?

Thanks!

Steve...

----- Original Message -----
From: <KGKIRKLEY@aol.com>
To: <astro-photo@seds.org>
Sent: Sunday, June 11, 2000 1:40 AM
Subject: Re: [APML] Adapting Nikon F3/T for gas purge


>
> In a message dated 6/10/00 3:35:49 PM, ireland@gate.net writes:
>
> >Hi all,
> >
> >
> >
> >I could use some advice on adapting my two Nikon F3/T bodies for a gas
> >purge
> >
> >system.  Living in South Florida (e.g. high humidity just about all of
> >the
> >
> >time), this is probably a necessary evil for the hypered PJ400 I like to
> >
> >use.
> >
> >
> >
> >Drilling through the tripod socket permanently alters the cameras, which
> >I'm
> >
> >not inclined to do.  So, it occurred to me that I could order two
additional
> >
> >camera backs, and drill through those instead.  I could use any advice
> >
> >anyone would have regarding how/where to drill; type of valves to use;
> >other
> >
> >equipment, etc.  By the way, I've ordered two additional standard F3
backs,
> >
> >not titanium ones.
> >
> >
> >
> >Ideally, it would be nice to rig up a system whereby one or both cameras
> >
> >could be used at the same time (with a splitter valve of some sort).
Also,
> >
> >sometimes only one camera would be used.  I plan to use Nitrogen, but may
> >
> >also consider the dry air purge.  It seems to me, however, if going to
> >this
> >
> >much trouble, I might as well use Nitrogen.
> >
> >
> >
> >Would appreciate any advice.
> >
> >
> >
> >R. Scott Ireland
>
> Scott:
> Using the interchangeable backs on the F3's is an interesting solution,
but
> N2 is usually introduced in front of the film, either in the mirror box,
> coupling adapter, or off-axis guider body. If introduced through the
camera
> back it's difficult for the N2 to get to the mirror box to keep the
emulsion
> dry. It will keep the film dry in the cassette and take-up area and may
> eventually get into the mirror box, forward of the shutter.
>
> Using nitrogen you will need serveral things:
> 1. Nitrogen tank of appropriate capacity
>     They usually come in 20, 40, 80, 200 cu. ft. sizes. In the smaller
sizes
> you
>      usually have to buy them. The 200 can be rented. For ease of
> transportation,
>      the 40 or 80 are best. The 200 is fine for permanent observatories.
> 2. Pressure regulator with Flow meter
>     The regulator controls and lowers the pressure.
>      The flow meter allows you to regulate the flow of N2 down to very
small
> levels.
>       The N2, tanks, regulator with flow meter are available from welding
> supply co.
> 3. I use drip-irrigation tubing and valves, available at Home Depost, etc.
>       All kinds of on-off, splitter valves are available and they are
cheap.
>       Once the N2 leaves the flow meter, there is very little pressure.
>
> If you proceed with the F3 Back N2 Introduction idea, please post your
> results.
> thanks,
> Kent Kirkley
>
>
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