[PSUBS-MAILIST] Gamma bow dome

Fri Feb 27 09:05:11 EST 2015

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
>>
>>
>>
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