Re: [PSUBS-MAILIST] Viewport Toughness

[Ian Roxborough <irox@ix.netcom.com>]

It boils down to pretty much one thing.  How much testing has
been done on the materials you are considering using?
I don't think that glass has had any where near the amount
of testing that Acrylic has had.  I've certainly not seen
any studies on the topic of glass view ports.  But if you where
to make a few hundred glass domes and destructively test
them (after various pressue cycling to simulate the life
cycle of the vessel you will be using them in - or at least
the life of the vessel until you replace the windows), then
you'd probably have enough data to decide if you would trust
your life to it or not.

Saying, that, one reason why I would choose Acrylic over glass
(other than the amount of test data available), is that Acrylic
will turn 'milky' (in color) long (hours? I don't really know
the duration) before you get to the point of failure.  This will
hopefully provide enough time to get the vessel to safety.

Ian.

On Fri, 10 Oct 2003 00:25:34 -0700
"Brian Cox" <ojaibees@ojai.net> wrote:

> I have a question about using a glass dome, wouldn't a thick glass dome actually stronger than acrylic?  But it would not be able to be used because of it propensity to shatter under certain types of stresses.    Adam ?
> 
> Brian Cox
>  
> ----- Original Message ----- 
> From: "Adam Lawrence" <adteleka@in-tch.com>
> To: <personal_submersibles@psubs.org>
> Sent: Monday, October 06, 2003 7:30 AM
> Subject: Re: [PSUBS-MAILIST] Viewport Toughness
> 
> 
> > From what I have read, when a viewport breaks it starts by extruding itself
> > into the flange and then final failure is like a shotgun going off. Also,
> > failure initiates on the inside surface, where the acrylic is in tension.
> > Test it, that's the only way you'll know!
> > 
> > Adam
> > 
> > 
> > ----- Original Message -----
> > From: "pierre&marie" <poulin.carrier@videotron.ca>
> > To: <personal_submersibles@psubs.org>
> > Sent: Monday, October 06, 2003 5:49 AM
> > Subject: [PSUBS-MAILIST] Viewport Toughness
> > 
> > 
> > > Hi People!
> > >
> > > I've been to a house building show here in cold Canada and there was a
> > boot
> > > that sold "unbreakable" windows for thief.
> > >
> > > They say that there technologie can change a normal window into a bullet
> > > proof window.
> > >
> > > The basic of that method is to put a high resistance thin plastic film
> > that
> > > stick on the window. Almost like a windshield. You should see me comming
> > > from now... I asked if we can put that film on acrylic and the said yes.
> > >
> > > Do you think that this could be helpful for psubs? It would not augment to
> > > strenght of the viewport but if it break it could prevent water from
> > comming
> > > inside the sub or prevent the viewport from imploding?
> > >
> > > Comments?
> > >
> > > Pierre "Viewport Strenghtener Technicien" Poulin
> > >
> > 
> > 
>