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Scott,
Pick up a
copy of the Handbook of Acrylics by Jerry Stachiw. You can order it
anywhere, including http://www.psubs.org/store/books/stachiw.html.
It has all the info you need to safely design and manufacture your
viewports.
Annealing is
part of the process to create a viewport that is being built to ASME
standards. When you (or port plastics) machine acrylic (ie, cut it into a
circle, buff, polish, etc) the acylic incurs forces that need to be relieved by
annealing, or heating slowly at a controlled rate to a prescribed temperature,
holding at that temperature for a certain time period, and then slowly reducing
the temperature at a controlled rate.
All this
information is in Stachiw's book. It's not rocket science, but there are
numerous variables that have to be considered and it would just take too long to
go over them all in email. In my opinion, Stachiw's book, ABS docs, and
ASME docs are prerequisites for submersible construction.
Frank, 325
degrees is too high for annealing and is used for forming (bending, twisting,
etc). Various temperatures can be used, and the lower the temperature the
longer the annealing time required, but 230F is the max temp for
annealing.
Vance, I'm
quite sure the price quoted to Scott does not include annealing. It's not
clear that the company even provides that service. However, they may have
pre-shrunk material that meets the MIL spec included in an earlier email.
Of course, annealing will still be required. I will be calling the company
rep later this afternoon and finding out all these details.
Jon
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