Brent,
As numerous people have stated before, get Stachiw out. For
a port see page 257 where he has various diagrams for mounting which include
some similar to what you are describing. Generally if you need to do
something with port and domes, it is in Jerry’s book. If you don’t
have a copy, you need to get one (which has also been stated numerous times
also).
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
Talk sense to a fool and he calls you foolish.
- Euripides (484 BC - 406 BC)
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
Hartwig
Sent: Saturday, August 30, 2008 3:50 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] O-Rings & Acrylic Ports
Hi All,
Thank you for the good data to chew on guys. When I was working on different
dome and flat viewports in the past, I didn't know about the hard neoprene type
gaskets, and that it was considered a good option in some applications. I was
interesting in another way to seal a dome or flat viewport that wasn't glued
in, in such a way that it was hard to remove for maintenance and/or
replacement. I now wish to use the hard gasket type seals in several
applications.
Do
you think there would be any advantage to adding a small raised lip to the
inside of the hard gasket in the dome or flat viewport seating flange? I was
thinking it might be useful to keep the gasket from extruding in towards the
interior. But since there is so many square inches of surface area on the
exterior of the dome and/or flat viewport, much of it pushing down. I
figure that there is far more pressure being transfered down to the domes or
flat viewports seating surface then is being applied to the very small surface
area on the outer most edge of the gasket.
The configuration I was thinking of would have a small gap between the lip and
the dome, say 1/8", and the gasket would be cut to fit tight against that
lip. this way the gasket wouldn't have room to move and the dome wouldn't be
affected by the lip. That grove that would be created would get condensation
water running into it and might be a little hard to clean, but there might be a
way to install a very soft gasket type seal in that groove to deal with that
issue. To add a small lip in the interior of a flat viewport seat would be a
little different and would need to be in my opinion, shorter to as to not ever
touch the flat acrylic viewport under full rated pressure. So in that configuration
one might want a thicker hard gasket.
The viewports seat being distorted from welding, I believe is a very good
point. This is why I was thinking about a way to make a poured type gasket, and
in some way coat, wax, etc. the viewport so you can remove it after the gasket
has cured. Then clean the viewport and install it for the final time in the
orientation it was when the gasket was formed. Perhaps the orientation will not
be a issue. This way you have a custom gasket that is not glued to your
acrylic. This is what I was thinking about doing for my front lower viewport on
my K-250 that has a lightly pitted seating surface. I'll smooth the seating
surface out a fair bit with epoxy paint, but even if I get it smooth, there
could well be some welding distortions to deal with. One could use a couple
light coats of PVA mold release agent sprayed on, and if the paper or plastic
protective coating is still on or could perhaps be reapplied on the flat
acrylic viewports, then that might be a good way to go. For the domes you could
add some things like that as well.
Your resident pipe dreamer ;)'
Regards,
Szybowski