Re: [PSUBS-MAILIST] acrylic sphere/lithium Hydroxide

[Ppjanca@aol.com]

The ultimate US source for acrylic hyperhemispheres is Reynolds Polymer 
Technologies, Inc. of Grand Junction Colorado (<A 
HREF="http://www.reynoldspolymer.com">www.reynoldspolymer.com</A>), ask for 
Kyle. In the UK you have the choice of Stanley Plastics or Blanson. All three 
have supplied me with PVHO acrylics in the past and with one single (UK) 
exception we have been most pleased with price and delivery. One big question 
to ask them is "what size tooling do you already have, and.... is it 
proprietary?"  Then design around their tooling inventory. I have over $250K 
invested in acrylic tooling and you had better not expect to purchase acrylic 
off of my tooling without some compensation. In many cases a few ice cold 
Coronas will be sufficient compensation if you are a serious builder and 
safety oriented.
A 66" hyperhemisphere with 5" nominal wall thickness should cost in the 
region of $160K.
AMRON International (<A HREF="http://www.amronintl.com">www.amronintl.com</A>
) sell  "off the shelf" scrubbers but they are relatively easy to make using 
a dual voltage vacuum cleaner motor (BUFFALO is one brand that comes to mind) 
so that you can run it at normal speed on 12/24 vdc and then boost the 
scrubbing action in stressful periods by switching to 120 vdc. I always 
prefer transparent (acrylic again NOT Lexan) canisters with "milk filters" 
upstream and downstream (top and bottom of the acrylic canister) to trap 
fines. The only grade used in commercial boats is "408 white to violet." By 
using the transparent canister you can see the color change take place.  It 
is probably unnecessary to say this but you want the scrubber intake to be as 
low as possible in the command compartment because co2 is a heavy gas. The 
most popular discussion in making scrubbers is "suck or blow." We always 
prefer to draw the command sphere/compartment atmosphere through the scrubber 
bed. My personal feeling is that I am tuned to hear the scrubber slow down 
and immediately suspect (1) low voltage (2) scrubber bed loading (dust or 
moisture).  Hopefully all of you know how to make a lung powered scrubber and 
have plans to do so!
Again, suck or blow is the big issue. Here the issue seems to be more 
personal pilot opinion.  In diving technology (wet type) we know that 
exhalation resistance can often be more distressing than inhalation 
resistance. For my money I will always scrub on the inhalation cycle!
We have used all of the popular co2 absorbents but I personally prefer 
Sofnolime. You can purchase directly from  <A HREF="http://www.oclugo.com">
www.oclugo.com</A> they presently have smaller containers in stock and are 
expecting a large delivery of the 44# "kegs" in a mid-October.
Another great source for small quantities of absorbent is Advanced Diver 
magazine 
<A HREF="http://www.advanceddivermagazine.com">www.advanceddivermagazine.com
</A>
Sorry for the long winded answers.
Best Regards:
Phillip Janca
Chairman
HyperTec, Inc.
World Leader in Hyperbaric Technologies
800-218-3588
940-564-5600
940-564-5609 Fax
http://www.hypertec.ws