[PSUBS-MAILIST] Gamma bow dome

Alec Smyth via Personal_Submersibles personal_submersibles at psubs.org
Fri Feb 27 11:34:35 EST 2015 

Yes, that drawing is exactly what I was trying to describe.



On Fri, Feb 27, 2015 at 10:49 AM, James Frankland via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:

> It took me about 5 mins to do the drawing on MS paint!
>
> I think you mean something like Stachiw's book, page 524 fig 11.76.
> Bottom drawing.  Probably will work just as well.  No machining required!
>
> On 27 February 2015 at 15:35, Alec Smyth via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> Thanks, you went to some trouble making that drawing, but it certainly
>> added clarity. In my case the outside wall of the acrylic is completely
>> square and there's virtually no gap at all between seat and window, its
>> literally a few thousandths. I could machine the seat to take an O-ring
>> groove, as you did with the retaining ring. However, PVHO 2-2.11.1 says "As
>> primary seals for standard window geometries shown in Figs. 2-2.1 through
>> 2-2.4, a soft elastomer compressed between the high pressure face of the
>> window and retainer ring will be acceptable. The soft elastomeric seal may
>> take the form of a flat gasket, or a seal ring with O, U, or X cross
>> section."
>>
>> Given its so easy to cut out a circular flat gasket, I think I'll try
>> that first and see how it goes. If there are nuisance leaks, I could
>> upgrade to an O ring by machining the appropriate groove, but I'll try the
>> lazy approach first. These bolt-on window seats are nice in that they allow
>> for later modification.
>>
>>
>> Best,
>>
>> Alec
>>
>>
>>
>> On Fri, Feb 27, 2015 at 9:56 AM, James Frankland via
>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>> Hi Alec,
>>>
>>> The epdm gasket was really just to relieve stress on the seat of the
>>> dome.  This was with advice from the guy who built the Canary island subs
>>> who came to visit me.  Although of course it should provide sealing at
>>> higher pressure.
>>>
>>> Emile made the dome and mounting ring and suggested I would need another
>>> seal for low pressure.  So, I made the low pressure seal an O ring sitting
>>> in a machined groove in the retaining ring.
>>>
>>> See hastily drawn picture.
>>>
>>> The gap where the O ring sits is nowhere near as severe as it looks in
>>> the picture, which is of course not to scale or anything.   I would love to
>>> say it was carefully engineered, but im afraid I just winged it a bit.  To
>>> start with the O ring groove was just a chamfer.  This didn't work as I
>>> couldn't get the O ring to stay in.  Then I machined it for a very small O
>>> ring.  Couldn't get it in.  Eventually, I got a groove and O ring
>>> combination that seemed to work.  There is lots of silicone grease on all
>>> surfaces as well.  It doesn't leak.
>>>
>>> Regards
>>> James
>>>
>>>
>>> ​
>>>
>>>
>>>
>>>
>>> ​
>>>
>>> On 27 February 2015 at 14:05, Alec Smyth via Personal_Submersibles <
>>> personal_submersibles at psubs.org> wrote:
>>>
>>>> Hi James,
>>>>
>>>> That's some good looking hardware! Just a question if I may. Do you
>>>> have just the gasket for making a seal, or is there an O-ring as well?
>>>>
>>>> My project sub has a bow dome seated in an aluminum ring. Currently the
>>>> window is just sitting on a gasket with no O-ring, but I'm wondering
>>>> whether to switch to an O ring. The window seat is 90 degrees square, so
>>>> one possibility would be to chamfer the edge of the acrylic and put an O
>>>> ring in the angle. That is what I did on Snoopy's hatch dome, it worked
>>>> well and is a solution that doesn't require any changes to the seat. The
>>>> other option is to put an O ring at the top of the acrylic and squeeze it
>>>> with the retaining ring, but that would mean machining a chamfer into the
>>>> seat, and would require machinery larger than what I have here. Or of
>>>> course I could do nothing and see if it seals well with just an EPDM gasket.
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Alec
>>>>
>>>> On Fri, Feb 27, 2015 at 8:40 AM, James Frankland via
>>>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>
>>>>> ​Hi Hank.
>>>>>
>>>>> Yes, agreed, my dome does sit on a gasket.  The actual edge of the
>>>>> acrylic itself sits on a 1mm epdm gasket that sits onto the aluminium
>>>>> ring.  That ring bolts to the main reinforcing ring and has an o ring like
>>>>> you say.  Maybe this does give it a little bit of leeway.
>>>>>
>>>>> My dome is off at the moment, so I will have a look at the weekend and
>>>>> see if I can see any distortion on the reinforcing ring.  Im pretty sure
>>>>> there is none, or none that is detectable by the naked eye\straight ruler.
>>>>> The alu ring seems to fis to it perfectly.
>>>>>
>>>>> I suppose the best option is like you say, get it machined after
>>>>> welding.  You wont have to worry at all then.
>>>>>
>>>>>
>>>>> ​
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On 27 February 2015 at 13:23, hank pronk via Personal_Submersibles <
>>>>> personal_submersibles at psubs.org> wrote:
>>>>>
>>>>>>
>>>>>> James,
>>>>>> I am just assuming it needs to be perfect ? and I can not imagine
>>>>>> that it will not warp at least a small amount.  I am not experienced with
>>>>>> how such heavy material will react. Your dome sits on a gasket witch may
>>>>>> give you some forgiveness. Maybe Emile can comment having done this also.
>>>>>> Hank--------------------------------------------
>>>>>> On Fri, 2/27/15, James Frankland via Personal_Submersibles <
>>>>>> personal_submersibles at psubs.org> wrote:
>>>>>>
>>>>>>  Subject: Re: [PSUBS-MAILIST] Gamma bow dome
>>>>>>  To: "Personal Submersibles General Discussion" <
>>>>>> personal_submersibles at psubs.org>
>>>>>>  Received: Friday, February 27, 2015, 7:28 AM
>>>>>>
>>>>>>  Do
>>>>>>  you need to go to all that trouble?  When I did mine, the
>>>>>>  reinforcing ring was milled flat on the seating surface and
>>>>>>  I just pre-heated it and welded it in.  It was so big I
>>>>>>  don't think there was any distortion and it doesn't
>>>>>>  leak. Just thinking of saving you
>>>>>>  what sounds like an expensive job.
>>>>>>  On 27 February 2015 at
>>>>>>  11:45, hank pronk via Personal_Submersibles <
>>>>>> personal_submersibles at psubs.org>
>>>>>>  wrote:
>>>>>>  James,
>>>>>>
>>>>>>  I am amazed at the equipment some of the big shops have. A
>>>>>>  vertical mill is probably the way to go.  I am checking out
>>>>>>  another option also.  There are machines made to machine
>>>>>>  pipe flanges that clamp on and are portable.  There is a
>>>>>>  company in Calgary that specializes in this. I am just not
>>>>>>  sure yet what the accuracy is yet.  It is nice that I live
>>>>>>  only 3 hr from a big oil town that caters to the oil
>>>>>>  industry.  You can tell that oil is low, and the shops are
>>>>>>  slower.  I ordered the ring on a Friday and it was ready
>>>>>>  Monday.
>>>>>>
>>>>>>  Hank    --------------------------------------------
>>>>>>
>>>>>>  On Fri, 2/27/15, James Frankland via Personal_Submersibles
>>>>>>  <personal_submersibles at psubs.org>
>>>>>>  wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>   Subject: Re: [PSUBS-MAILIST] Gamma bow dome
>>>>>>
>>>>>>   To: "Personal Submersibles General Discussion"
>>>>>>  <personal_submersibles at psubs.org>
>>>>>>
>>>>>>   Received: Friday, February 27, 2015, 4:08 AM
>>>>>>
>>>>>>
>>>>>>
>>>>>>   Hi hank,Sounds like
>>>>>>
>>>>>>   it will be a good
>>>>>>  modification.  How are they going to
>>>>>>
>>>>>>   machine the ring?  Some sort of vertical
>>>>>>
>>>>>>   mill?RegardsJames
>>>>>>
>>>>>>
>>>>>>
>>>>>>   On Friday, 27 February 2015, hank pronk via
>>>>>>
>>>>>>   Personal_Submersibles <personal_submersibles at psubs.org>
>>>>>>
>>>>>>   wrote:
>>>>>>
>>>>>>   Today I
>>>>>>
>>>>>>   officially took the plunge and removed the forward
>>>>>>  ballast
>>>>>>
>>>>>>   tank to install my new bow dome.  After much agony I
>>>>>>
>>>>>>   decided to make the change.  I am not enjoying the sub
>>>>>>
>>>>>>   because the forward window arrangement is not ideal for
>>>>>>
>>>>>>   lakes with marginal visibility.  I went to the big
>>>>>>  city
>>>>>>
>>>>>>   yesterday and picked up the reinforcing ring and should
>>>>>>  have
>>>>>>
>>>>>>   it fitted in a couple of days.  I am bringing in a
>>>>>>  pressure
>>>>>>
>>>>>>   welder to weld the ring and then the sub is off to the
>>>>>>  big
>>>>>>
>>>>>>   city to machine the ring.
>>>>>>
>>>>>>
>>>>>>
>>>>>>   Hank
>>>>>>
>>>>>>
>>>>>>
>>>>>>   _______________________________________________
>>>>>>
>>>>>>
>>>>>>
>>>>>>   Personal_Submersibles mailing list
>>>>>>
>>>>>>
>>>>>>
>>>>>>   Personal_Submersibles at psubs.org
>>>>>>
>>>>>>
>>>>>>
>>>>>>   http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>   -----Inline Attachment Follows-----
>>>>>>
>>>>>>
>>>>>>
>>>>>>   _______________________________________________
>>>>>>
>>>>>>   Personal_Submersibles mailing list
>>>>>>
>>>>>>   Personal_Submersibles at psubs.org
>>>>>>
>>>>>>   http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>  _______________________________________________
>>>>>>
>>>>>>  Personal_Submersibles mailing list
>>>>>>
>>>>>>  Personal_Submersibles at psubs.org
>>>>>>
>>>>>>  http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>>>
>>>>>>
>>>>>>
>>>>>>  -----Inline Attachment Follows-----
>>>>>>
>>>>>>  _______________________________________________
>>>>>>  Personal_Submersibles mailing list
>>>>>>  Personal_Submersibles at psubs.org
>>>>>>  http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> Personal_Submersibles mailing list
>>>>>> Personal_Submersibles at psubs.org
>>>>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Personal_Submersibles mailing list
>>>>> Personal_Submersibles at psubs.org
>>>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> Personal_Submersibles mailing list
>>>> Personal_Submersibles at psubs.org
>>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>>
>>>>
>>>
>>> _______________________________________________
>>> Personal_Submersibles mailing list
>>> Personal_Submersibles at psubs.org
>>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>>
>>>
>>
>> _______________________________________________
>> Personal_Submersibles mailing list
>> Personal_Submersibles at psubs.org
>> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>>
>>
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20150227/e58ee54a/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Dome222.jpg
Type: image/jpeg
Size: 53468 bytes
Desc: not available
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20150227/e58ee54a/attachment-0002.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: dome.jpg
Type: image/jpeg
Size: 76376 bytes
Desc: not available
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20150227/e58ee54a/attachment-0003.jpg>

More information about the Personal_Submersibles mailing list