Hi Andre,
I’m not an expert on domes, but I agree with David that the O-ring groove is in a dangerous spot. You could, for instance, chamfer the outside edge and put the O-ring there (see photo on the Snoopy project page). In addition, careful with the drawing on the left and stress concentration at the flange. Domes are made with a flange like that, but it should be machined off because during fabrication it will have accumulated stress. When a shoulder is used, as in the K250 domes, it is a bonded shoulder.
Viewports are an area where one can very easily get something wrong with catastrophic consequences. I would highly recommend purchasing a dome from someone like Greg or Emile. It will come with free advice worth more than the dome itself. Of all the things one has to build for a sub, this is one of the areas with the most specialized fabrication requirements. I find viewport design is not a problem if you get a copy of the PVHO, which should be considered mandatory reading and is more or less a collection of recipes. But fabrication is something else altogether, and to get to where the dome fabricators are has them years of trial and error.
Thanks,
Alec
The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it. From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of André Eriksen From what you said I made this sketch (attached). Is this a good way to fasten the dome? -Andrè 2012/6/15 Emile <emile@airesearch.nl> Hi Andre, It is not done to drill / tap any holes in a acrylic dome. Stressraiser! For shallow divers you can glue . Under high pressures the dome contracts more than the ring I use a o-ring on the edge and stainless steel bands hold down the dome. Flange also possible for shallow divers. In the handbook of acrylics are some examples. Emile Van: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] Namens André Eriksen Hi, I`m new to this forum, and are planning to build a 3 person sub. I can`t seem to find any plans or pictures on how to fit the acrylic dome for the hatch. Is it screwed down on flanges with an o-ring underneath, or liquid gasket/glue? I`ve seen some domes without flanges, how do they attach them? thank you. -Andrè Eriksen, Norway
Sent: Friday, June 15, 2012 4:16 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] how to fit the acrylic dome
Verzonden: vrijdag 15 juni 2012 17:25
Aan: personal_submersibles@psubs.org
Onderwerp: [PSUBS-MAILIST] how to fit the acrylic dome