-----Original
Message-----
From: Jon Wallace <jonw@psubs.org>
To:
personal_submersibles@psubs.org
Sent: Tue, Sep 21, 2010 2:02 pm
Subject:
Re: [PSUBS-MAILIST] Sub as panoramic film platform ( viewport flange and lens
fit)
Brian,
You
could also use an o-ring around the circumference of the lens if your
thru-hull retains its circular shape after welding. That would alleviate
the issue of the o-ring sealing on the outside of the lens. See
"Handbook of Acrylics" page 254.
Jon
On 9/21/2010 12:22 PM,
Brian Cox wrote:
Thanks Dan, My lenses will be
6" in diameter and 1 1/2" thick and my flanges are pretty beefy with
3/4" thick wall and 3/4" seat. I think with care hopfully
I won't see any significant distortion after welding. If I
end up with some variation with how the lens is flush with the top of the
flange I could vary the thickness of the gasket material on the seat to
bring the lens up or down. The lens needs to be flush with the top of
the flange because the O ring has to get compressed by the outside
retaining ring. I will have a V notch on the edge of the lens.
The gasket on the seat also will act to seal the water
out.