Brian,
Distributors are unlikely to want involvement of making special cuts,
at least without a surcharge for the inconvenience. You are describing
a remnant that may or may not be available and probably have a better
chance of asking someone like Precision Plastics if they have anything
left over from some other work that they could send your way.
By the way, 1.5 thickness sounds high for your application. Are you
still designing for 500 foot depth? My calculations show a six inch
disc providing an inside diameter viewing area of 4.8 inches and a
critical pressure of 6090 psi or 13,685 feet. It looks like you could
use 1 inch material and still have a correction factor of near 5.
Jon
On 9/22/2010 11:54 AM, Brian Cox wrote:
In my case I need eight 6" viewports 1 1/2"
thick, is there any way just to get a rectangular piece 14" by 28" and
have that shrunk?
brian
I'll see what I can work out with Polycast. The problem is always
going to be finding "a bunch of guys" who are ready to invest in the
material at the same time as anyone else. You might recall that
Kittredge provided (8) eight-inch viewports for sale on PSUBS a few
years ago, and it took about 3 years before they finally all sold.
That was much longer than I ever thought it would take to sell them.
So your chances of finding someone ready to purchase acrylic at the
same time you are ready, may not be as high as we would like to think.
The cost for a sheet is not cheap. Eplastics is showing $2,584 for
1.5x48x96 sheet, however without specifications I don't know if that
particular material is PVHO rated and would assume it wasn't.
Depending upon the cost, PSUBS may be able to absorb the investment in
PVHO approved material and holding it. Segments could then be
"ordered" via the website. Perhaps members get it at cost and
non-members pay some higher amount. We'll can talk about this further
on the member forum depending upon what I get out of Polycast.
Jon
On 9/22/2010 9:45 AM, Greg Cottrell wrote:
So what to
do? Get a bunch of guys together, go in on a full sheet of pre-shrunk
polycast (that will be very flat and distortion-free) chop this sheet
up into smaller pieces, machine them into viewports, and then anneal
the parts in accordance with the schedule in Stachiws book. No fuss no
muss.
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