Re: Re: [PSUBS-MAILIST] Using a commercially available hatch as an emergency esca...

["Herve" <caribsub@coqui.net>]

There is confusion here between materials and tradenames.
Lexan, plexiglass... trade names.
materials are actually: polycarbonate or acrylic.
polycarbonate better fits view ports and windows for submersibles although
soft enough to be scratched and wornt out rapidly.
Tempered glass cannot be used in 1 atm subs, ambient pressure subs allow use
of tempered glass which is much more better for viewing, clarity and are
scratch proof.
Tempered glass is a heat treatment of glass which renders the glass
frangible in case of shock to avoid projection of sharpened pieces of glass,
in the process the glass actually gain 4 times the strengh of the regular
glass.
Greg , Dont need an escape hatch either since the windows  could be
shattered with the apropriate tool in case of an emergency and to get out.
Herve
----- Original Message -----
From: <rjune@fuse.net>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, May 08, 2002 3:18 PM
Subject: Re: Re: [PSUBS-MAILIST] Using a commercially available hatch as an
emergency esca...


> I think you've got it backwards.
> I have both lexan and plexiglass downstairs.
>
> I can pound away on a piece of 1/4 inch lexan
> with a 2 pound ball peen hammer and only dent it.
>
> and 1/2 thick plexiglass shattered after one hit.
>
> not only that but lexan can easily be machined,
> drilled, and even tapped.
>
> Additionally, I volunteer at a local aquarium,
> where we have tunnels constructed of lexan
> the floor in one of the tunnels is a flat pieces of
> 3" thick lexan and has a rated capacity of 6000 lbs.
>
> an additional thought ... the same piece of lexan
> was installed when the aquarium was built over
> five years ago and sees the foot traffic from
> 1000 to 2000 people 300 plus days a year and it still
> looks good
> >
> > From: Ray Keefer <Ray.Keefer@Sun.COM>
> > Date: 2002/05/08 Wed AM 11:54:59 EDT
> > To: personal_submersibles@psubs.org
> > Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch as an
emergency esca...
> >
> > Hi,
> >
> > I worked in a plastic fabrication shop in my starving student days.
Everyone
> > got nervous when they had to cut lexan. Occasionally it would catch in
> > a saw blade and kick back in shards. It is tougher then plexiglass but
> > brittle also.
> >
> > Regards,
> > Ray
> >
> >
> > > From: DBACKIDS@aol.com
> > > Date: Wed, 8 May 2002 00:05:30 EDT
> > > Subject: Re: [PSUBS-MAILIST] Using a commercially available hatch as
an
> > emergency esca...
> > > To: personal_submersibles@psubs.org
> > > Content-Transfer-Encoding: 7bit
> > >
> > > Quick note on using Lexan: If you plan on cutting it yourself, be
careful,
> > > for it shards like a glass would, not melts right through like plexi
would.
> > > (I built a 5" x 9" x 3' long "wet wind tunnel" (a wind tunnel, with
water
> > > instead of air), and found out that plexi, when cut fast, practically
melts
> > > itself back together, while lexan will shard off unless it is covered
or
> > > taped. It was a fun project, too) Ok, I went off-track, but you got
the
> > > point.
> >
> >
>
>
>