Re: [APML]: Hypering Experiments

[Chuck Vaughn <aa6g@aa6g.org>]

Philip,

>Experiment 1
>------------
>Today I set up Batch 031 - a 'pseudo hyper'  - standard hyper in every way 
>except for one thing: there was no film in the tank. Description follows.
>
>Pre-warmed tank for 30 mins. Started pumping at 11:52 - temperature 42 C 
>5 evac / fill cycles - evacs to -27 psi, fills to 0 psi. 6th fill to +3 psi
>Stopped pumping / started 'hypering' 12:00 noon - temperature 48 C 
>Placed tank under thermal cover - temperature reached 50 C by 12:04 
>Double checked pressure at 12:04 still exactly on +3 psi 
>Pressure checked every hour - remained exactly on +3 psi throughout 
>Final pressure check 19:31 (as I write) - still reads exactly +3 psi

I think when you say -27 psi you mean -27 inches. The guage is inches on
the negative side and psi on the positive side.

This is sort of the test I ran escept I didn't preheat the chamber showing
that heating gas causes a pressure increase.

In your next test you hypered four rolls of film while I've only hypered
two at most. It still seems like a lot of gas to me (2 inches) but it's
hard to argue with results.

After pulling a high vacuum on Tech Pan I only see the 1 psi increase in
pressure when heating the tank, the same as I saw with no film in the tank.
This tells me that my film has essentially no water or O2 left in it.

>Even though this has yet to be proven, there's more than 90% certainty in my
>mind that I am hypering my films in a mix of forming gas and water vapour,
>and it's this that I am trying to avoid.  Even in the event that this is not
>mostly water vapour, it is still a contaminent and should be expelled prior
>to hypering.

It sounds like the only way to get it out is to pull a high vacuum on it.
Heating for a long time might do it but the film will be too fogged to be
useful. The vacuum introduces no fog.

Chuck  <aa6g@aa6g.org>