[PSUBS-MAILIST] Gamma needs a diet

hank pronk via Personal_Submersibles personal_submersibles at psubs.org
Sat May 17 19:43:58 EDT 2014 

That is pretty good stuff, 6ish lb buoyancy per imperial gal of volume.  
Is it reasonable to think a regular guy in a regular shop can produce comparable quality and performing material.

--------------------------------------------
On Sat, 5/17/14, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] Gamma needs a diet
 To: personal_submersibles at psubs.org
 Received: Saturday, May 17, 2014, 7:26 PM
 
 
 
  
  
 
 Hank,
 Here's a chart for a starting point: 
 http://www.diabgroup.com/~/media/Files/Products/Core-material-pdf/BMTI%20Selection%20Guide%20-%20October%202013.pdf
 Cliff used it somewhat in the R-300.  I don't
 have hands-on 
 experience.  This search will give you a bunch of other
 links:
 http://search.aol.com/aol/search?enabled_terms=&s_it=wscreen-smallbusiness-w&q=density+of+syntactic+foam
 Jim
  
 
 In a message dated 5/17/2014 6:17:39 P.M. Central
 Daylight Time, 
 personal_submersibles at psubs.org writes:
 Jim,
 What kind of numbers are we talking here. How much volume 
   of foam per lb of 
   buoyancy.
 Hank
 --------------------------------------------
 On Sat, 
   5/17/14, via Personal_Submersibles
 <personal_submersibles at psubs.org> 
   wrote:
 
 Subject: Re: [PSUBS-MAILIST] Gamma needs a diet
 To: 
   personal_submersibles at psubs.org
 Received: Saturday, May 17, 2014, 7:11 
   PM
 
 
 
   
   
 
 Hank,
 Greatest net buoyancy on 
   your syntactic foam is
 achieved by mixing larger 
 spheres with smaller 
   spheres so the smaller ones fit in the
 gaps between the 
 larger 
   ones.
 Jim
  
 
 In a message dated 5/17/2014 6:04:36 P.M. 
   Central
 Daylight Time, 
 personal_submersibles at psubs.org 
   writes:
 Sean,
 Very interesting, I just googled glass microspheres and 
   
    this is very 
    
   doable.
 Hank
 --------------------------------------------
 On Sat, 
   
    5/17/14, Sean T. Stevenson via
 Personal_Submersibles 
   
    <personal_submersibles at psubs.org> 
   wrote:
 
 Subject: Re: 
    [PSUBS-MAILIST] Gamma needs a 
   diet
 To: "Personal Submersibles General 
    Discussion" 
   <personal_submersibles at psubs.org>
 Received: Saturday, May 
   
    17, 2014, 6:34 PM
 
 Hollow
 glass microspheres in a 
   (typically) epoxy 
    matrix. The
 spheres are so small, 
   they're more like a powder (for a
 deep 
    / dense foam. 
   Shallower foams will incorporate larger
 spheres). Mix the 
    
   composite with the highest possible volume
 fraction of glass to 
   
    resin.
 Sean
 
 
 
 
 On May 17, 2014
 4:09:46 
   PM MDT, hank 
    pronk via 
   Personal_Submersibles
 <personal_submersibles at psubs.org> 
   
    wrote:
 How is syntactic foam made.
   I once 
   experimented with 
    3/4inch plastic water line (pex
 pipe), 
   the stuff we plumb houses with now. 
    I heated the end
 of a 
   piece and it melted shut nicely.  So I planned 
    to 
   make
 a bunch of pipes with both ends melted shut then slide a
 bundle 
   
    of them inside a pvc pipe.  Then fill the
 void 
   with
 poly urethane 
    molding resin.  It would be cheap 
   and pretty
 tough.  Perhaps an 
    experiment is in order, 
   unless there is a
 better idea out 
    there.
 Hank
 
 On 
   Fri,
 5/16/14, Sean T. Stevenson via 
    
   Personal_Submersibles
 <personal_submersibles at psubs.org> 
   
    wrote:
 
 
 Subject: Re: [PSUBS-MAILIST] Gamma needs a 
   diet
   
    To:
 "Personal Submersibles General 
   
    
   Discussion"
 <personal_submersibles at psubs.org>
   
   
    Received:
 Friday, May 16, 2014, 7:12 PM
   
   
   
    There's
 always the not-so-easy but
   
   very elegant solution 
    of
 syntactic
   foam filled 
   hydrodynamic fairings.  
    Go
 bigger than you
   
   need to
 
 accommodate future expansion, 
    and compensate 
   in the
 meantime
   with keel
   weight.  
   
    Would improve
 stability, too.
   
   
   Sean
   
    
   
   On
 2014-05-15 18:51, 
   hank pronk via 
    Personal_Submersibles
 
 wrote:
   
   Alan,
   That would work 
    but
 I want to keep the sub 
   clean on the
 
 outside.  Gamma is 
    very slippery 
   the way it is.  I
   am confident I can shed the 
    
   weight.  I have been
 
 weighing all the bits and it looks 
   
    doable.  I am also
   looking at a winter 
   project for 
    Gamma.  I would like
 to
   have 
   the arm, and valve and a 
    couple 
   of
 positioning 
   thrusters on a common chassis, 
   
    like
 the DW's.  I could
   reduce the weight 
   of the
 lead 
    drop weight because the entire
   
   assembly would be
 the drop 
    weight.  That also 
   solves
   the weight
 problem from the 
    
   batteries.  I would use the
   
 original drop weight screw to 
   
    drop the new assembly.
   Hank
 
   On 
   Thu,
 5/15/14, Alan 
    James via 
   Personal_Submersibles
   
    
   <personal_submersibles at psubs.org>
   wrote:
 
   
   
    Subject: Re:
 [PSUBS-MAILIST] Gamma needs a diet
   
   To:
 "Personal 
    Submersibles General Discussion"
   
   
    <personal_submersibles at psubs.org>
   Received: 
   Thursday, May 
    15,
 2014, 8:17 PM
   
   
   Hank,a
   
    simple
 solution would be to just have 
   a
   number of floats
 like 
    Alec's 
   Snoopy.He
   has them in a tube, but
 if the floats 
    
   had
   attachment ho!
   les
   you 
    
   couldtether
  
 them & clip them on or off.Alan
   
   
    
  
       
   
    From: hank 
    pronk via
   
   
    
   Personal_Submersibles
  
 <personal_submersibles at psubs.org>
    To:
  
 personal_submersibles at psubs.org
   
   
    
    Sent: Friday,
   May 16, 
   2014 12:04 
    PM
    Subject:
   
   [PSUBS-MAILIST] Gamma needs a 
    
   diet
  
    
   Gamma or the pilot needs 
   
    to go to
 Jenny
   Craig.  My 
   new
  
 AGM batteries 
    weigh 73 lbs each and Gamma 
   has a
   60 to 65 lb
  
 weight 
    budget, per 
   battery. That means Gamma
   needs to 
    
   shed
  
 some lbs before I can take a passenger.  I
   
   
    can switch
  
 to aluminum scuba tanks, not sure 
   the 
    weight
   saving
  
 there.  I can 
   make an aluminum 
    rudder and a
   few 
   other
  
 parts also.
   
    
   Hank
 
  
 Personal_Submersibles mailing 
    
   list
  
 Personal_Submersibles at psubs.org
 Â!
     
   
   
   
 http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
   
   
    
   
 
       
   
  
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