[PSUBS-MAILIST] Foam preperation

Thu Jun 27 16:41:55 EDT 2019

Brian,
If I had $3million spare I wouldn't spend it on syntactic foam.
The danger is that if you were descending you might not know that you
were becoming negatively buoyant until you tried to stop. Then when 
you tried to counter by filling the ballast tanks with air; because of the compression
of the air at depth this might be a slow process.
Bottom line is not to dive the sub in depths that are beyond your maximum
dive depth till you are confident the foam isn't compressing.
Alan

> On 28/06/2019, at 7:41 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,       I don't have 3 million dollars.    In any event I only need it to go to 300 psi, theoretically ,   I also have about 1000 cu ft of air on board and could easily fill my ballast many times over even if the foam were to shrink.  I don't think the foam has an elastic property to it.  
> 
> 
> Brian
> 
> 
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Fri, 28 Jun 2019 07:33:33 +1200
> 
> Brian,
> as Cliff says it may have a volumetric change under pressure that leaves
> you negatively buoyant. I am not sure how you would test this in a 
> pressure chamber.
> As an example, a soccer ball could take a lot of pressure & look perfectly
> fine after a pressure test even though it might have been reduced to a 
> fraction of its original size in the process.
> I was told that Alvin's syntactic foam & testing process cost $3 million.
> They put it together in segments after testing each individual segment.
> It might be perfectly OK though...
> Alan  
> 
> On 28/06/2019, at 7:03 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> I have a pressure gauge guy who does oil industry work that I think has a small chamber where I could test a plug of foam.
> 
> Brian
> 
> 
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
> To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Thu, 27 Jun 2019 11:37:26 -0700
> 
> Cliff,
>               It's rated for 580 psi.
> 
> Brian
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Thu, 27 Jun 2019 15:55:01 +0000 (UTC)
> 
> Brian, this is not syntactic foam.  It's made for marine service but not for deep submergence.  It is really for surface buoyancy. I would not use this if you are relying on it for buoyancy at depth.   It is the macro-spheres and microspheres in syntactic foam that prevent it compression at depth.  I don't think this foam has either.
> 
> Best Regards
> 
> Cliff
> 
> 
> On Thursday, June 27, 2019, 10:45:29 AM CDT, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Clifff,   Here is the foam, it's the most dense foam , the 16lbs / cu ft
> 
> http://www.uscomposites.com/foam.html
> 
> 
> suppose to be good to 580 psi  
> 
> Brian
> 
> 
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Thu, 27 Jun 2019 14:29:12 +0000 (UTC)
> 
> Brian, I have been tied up and have not had a chance to follow this thread but I wanted to make sure you understand that unless this pour-able 2 part foam has a filler like 3-M's glass micro-spheres or some kind of incompressible macrosphere, then while the foam may appear rigid, it would compress when subjected to deep water and thus your buoyancy would be reduced.   I don't think this is a replacement for syntactic foam if that is what you are doing.  Can you send a link to the foam you are using?
> 
> Best Regards  
> 
> On Wednesday, June 26, 2019, 10:30:48 PM CDT, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Hi everybody,
>                                    I poured a small test piece of that 16 lb foam, man that stuff  gets as hard as a rock !  very dense , and very light.   This pouring of the foam is not going to be as straight forward as I thought,  The barrier to contain the foam is working out good, I'm just using wood and thin  1/8" luan ,  then I'm covering that with 4 mil flexible plastic ( heavy garbage type bag)  so the foam won't stick to it.  But I'm worried that any little gaps I have and the liquid foam might run out the bottom of those areas before it starts foaming, so I'm cramming big blankets ( cheap moving blankets from harbor freight)  in tight to contain any foam.  That way I can get the cavity that I'm trying to fill completely maxed out.  Waiting for an 80 + degree day  .   
> 
> Brian
> 
> 
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
> To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Mon, 24 Jun 2019 16:12:46 -0700
> 
> My first batch of foam cam today !  yay !   two five gallon pails, A and B,  should be interesting !
> 
> Brian
> 
> 
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Foam preperation
> Date: Fri, 21 Jun 2019 17:47:56 +0000 (UTC)
> 
> Brian,
> Did you find foam to fill the void?
> Hank
> 
> On Thursday, June 20, 2019, 8:30:55 PM MDT, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Kind of unnerving drilling holes in my boat !
> 
> 
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