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

[Coalbunny <coalbunny@onewest.net>]

What are the depth/pressure limits for glass and plexiglass?  What about
bullet-proof glass?
Carl


Herve wrote:
> 
> 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.
> > >
> > >
> >
> >
> >

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