Re: [APML]: Hypering thread ...

[Chuck Vaughn <aa6g@aa6g.org>]

Philip Perkins wrote:
> 
> This pressure rise is very significant - from 3 psi to as much as 5 psi,
> and has been very widely observed, although by differing degrees, which is
> almost certainly explained by differing film conditions, pre-hypering
> conditions, and temperatures used during actual hypering.

I think your summary sounds reasonable to me. Considering the high vacuum
I'm using to remove the majority of gases from the film, it makes sense 
that I see no pressure increase after the tank is temperature stabilized.
I consistently see about 1 psi increase from room temperature to 50 C and
that's it.

Does the procedure of exchanging the gas during hypering have any impact
on the film? There's one thing you can check. How long does it take to
hyper the film? If it's really had an impact the time should decrease. High
vacuum hypering can decrease the time for TP by a factor of 10. If your
hypering time remains the same with or without gas exchanges then it's
probably not making much of a difference. The less time you have to expose
film to heat the better.

Chuck  <aa6g@aa6g.org>