[PSUBS-MAILIST] syntactic foam.

Sat Jun 10 20:12:14 EDT 2017

Hank,
Using a phase changing material might alleviate one of the challenges that arise when making buoyancy foam with two part resin- the heat created limits the amount that can be poured at one time. A large section can sometimes require many pours. Too much heat and the resin will boil and be ruined.
If the wax works at depth, I don't see any reason that very thick ( and cheap!) sections couldn't be done at one time. In theory the wax could be melted and poured in a vacuum chamber.
Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, June 10, 2017 6:44 PM
 Subject: Re: [PSUBS-MAILIST] syntactic foam.

Alan,Luckily I have lots of time to work this out.  After looking at the cost for home made foam, it is not bad at all.  I will of coarse keep looking at other ideas, like the wax, that would have never occurred to me.Hank 

    On Saturday, June 10, 2017 4:18 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,I saw a number of syntactic foam samples at the Underwater InterventionConvention. The microspheres on the samples for deep diving were tiny.The deeper you go, the smaller the spheres. That idea might have meritdepending on how deep you were going, as it would be easier to work withthe larger spheres. However if you spent the extra money on resin rather thanoil you would have a rigid product.On Alvin I believe the foam was in sections that were pressure tested individually.I think you can get an imploding chain reaction, hence the multiple sections soyou don't put all your eggs in one basket.Alan

Sent from my iPad
On 11/06/2017, at 9:04 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Greg,That is a pretty interesting idea.  I would have to do some math, because the spheres gain a lot of strength when reinforced with resin.   Very interesting, I would not have thought of that.Hank 

    On Saturday, June 10, 2017 1:40 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,
The density of paraffin wax is about 10% less than water and liquefies at about 155 F.  You can buy it in bulk online (10 lbs cost about 20$).
Greg

      From: james cottrell via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, June 10, 2017 2:48 PM
 Subject: Re: [PSUBS-MAILIST] syntactic foam.

Hank,
I like your idea. What if you were to use an environmentally friendly oil that is a solid at room temps? In other words heat it to liquid state , pour it in the spheres and let it solidify?
Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, June 10, 2017 1:44 PM
 Subject: [PSUBS-MAILIST] syntactic foam.

I have an idea, but not sure if it will work.  My idea is to fill a neutrally buoyant container with macro and micro spheres.  After the container is as full as possible, then fill with an environmentally friendly oil.  This would be more buoyant than using a resin and less complicated and cheaper.  My concern is, how well will the spheres stand up against breaking from being in contact with the other spheres and the container.   Are these spheres delicate?  Hank_______________________________________________
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