Re: [PSUBS-MAILIST] acrylic dome

It would work except for one thing- glued joints are only suitable if the forces acting on them are only compressive forces. The orientation of the joints in your laminated dome would cause them to be subject to tensile and shear forces. This is why ABS will approve a radial glue joint in a sphere but not laminated viewports.

Greg Cottrell

Project Manager

greg@precisionplastics.com

http://www.precisionplastics.com

P please consider the environment before printing this email

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Alan James
Sent: Tuesday, September 21, 2010 5:25 PM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] acylic dome

Greg,

Prompted by Jon's dilemma re viewports & wanting to get down to 1000 ft, I'm

forwarding this idea for your scrutiny.

I've had thoughts about making a dome by stacking 2 rings of 100mm (4") thick

acrylic on top of each other & a disk on top of that, & gluing together.

The first ring starts off as a 600mm (24") circle cut out of a block of 100mm thick cast acrylic.

Then a 500mm circle (disk) is cut out of that. This disk is kept to go on top.

Another disk is cut & ring formed slightly smaller than 600mm diameter with a wall slightly larger than

50mm wide.

So you end up with 2 donuts stacked on top of each other & a disc on top of this.

You either glue them together & machine them to a dome or machine them close, glue them & sand & polish.

This would use about 1.2 meters x 600mm of 100mm thick cast acrylic, & give you a dome 40-50mm thick.

Possibly a dome that would get you a 1000ft operating depth for under $4000-.

If you used a larger diameter for the bottom ring you could machine a flange on it too

The person who blew my dome told me the joins would be invisible unless at eye level looking straight at the join.

Any thoughts on this idea thanks.

Alan