[PSUBS-MAILIST] Foam preperation

Thu Jun 27 19:17:45 EDT 2019

Brian this would only be a good test if you had a camera on it with a ruler.  I believe it would compress significantly then expand when you took back to surface.  Without microspheres and or macro spheres, there is just nothing to keep the entrained air from shrinking .  The pressure rating you need is what pressure you can take without any change in volume.

Cliff 

Sent from my iPhone

> On Jun 27, 2019, at 5:01 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> I think what I might just do is just go out in my sailboat , off Pt. Magu,  and drop a test plug down to 600' , bring it back up and check it out.  Need to go out for a sail anyway !  
> 
> 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 08:41:55 +1200
> 
> 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 !
> 
> 
> _______________________________________________
> 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
> _______________________________________________ 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/20190627/c9bcf03d/attachment-0001.html>