[PSUBS-MAILIST] Acrylic & distortion

[Alan James]

Hi Joe,
it is do-able if you stick to a basic shape. 
You could blow 2 ellipticle hemispheres & join them at the flanges &
mount them under a frame that extends from the hull.
Greg's the best person for advice on this.
Alan



________________________________
 From: Joe Perkel <josephperkel at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Tuesday, January 14, 2014 4:02 PM
Subject: Re: [PSUBS-MAILIST] Acrylic & distortion
 


Alan,

I don't have that text yet, every time I think to buy one I get a weeks worth of groceries instead! :)

 Joe

On Jan 13, 2014, at 7:53 PM, Alan <alanlindsayjames at yahoo.com> wrote:


Joe,
if you look in the Stachiw book on acrylic you'll see that light is distorted
as it moves through acrylic, & the longer it travels through it the more distortion.
So looking straight through a thin section, not so bad, but looking through 
the curves formed in an object made of acrylic would give more distortion.
The impact resistance would be a problem for a ballast tank. When 
forming a rounded shape from acrylic there is a thinning at the apex. 
For a blown hemisphere dome the thickness at the apex is about a 3rd of the 
original sheet thickness. So you would have to start with a relatively thick sheet.
You would have to connect it to the hull, & this would be a problem as these
connections would be stress points that could produce cracking.
Hope that's thrown cold water on the idea. (sorry can't find smiley button on ipad)
Alan

Sent from my iPad

On 14/01/2014, at 1:05 pm, hank pronk <hanker_20032000 at yahoo.ca> wrote:


Joe,
>If the acrylic is wet on both sides it disappears. 
>Hank
>
>
>
>On Monday, January 13, 2014 4:52:33 PM, Joe Perkel <josephperkel at yahoo.com> wrote:
> 
>What can I get away with as far as transparent see thru panels and not horribly distort the visual field?
>
>For example, large transparent panels that double as MBT shell. Any rules of thumb, curvature direction, compound curves vs developable surfaces, etc?
>
>Joe
>
>Sent from Yahoo Mail for iPad 
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