Materials to avoid

Packhorse · 16th January 2008, 00:48

I hear that PVC should be avoided in the breathing loop as it may off gas some particularly nasty chemicals. And yet I see may homebuilds using PVC.
What are you thoughts on PVC? Is there a type that is OK to use?
What other materials should be avoided? Eg aluminium due to corrosive issues? What about materials for the counterlung? Is neoprene or urethane backed cordura OK?

It would be a shame to build a safe rebreather only to die of lung cancer 5 years on.

OceanOpportunity · 16th January 2008, 00:56

aluminum is used in many of the commercial units, so is ok. anodized is better of course to reduce oxidation issues.

PVC that is used for potable water is fine. actualy, most solid state PVC is incredibly stable. its the adhesives you have to worry about

cstmwrks · 16th January 2008, 01:33

Quote: (Originally Posted by OceanOpportunity)

most solid state PVC is incredibly stable. its the adhesives you have to worry about

Thats why I took up the art of plastic welding with a heat gun and fill rod.. Just one more spendy item to buy to save money on that home build!

lizardland · 16th January 2008, 10:14

Be careful with some sealants as they offgas a weak acid (i.e. vinegar) during curing. They take a surprising amount of time to fully cure and the vapours are irritating if you have them in a breathing loop. I found out the hard way

Mdemon · 16th January 2008, 11:38

PVC, ABS with nasty plasticisers.

Polyprop is supposed to be OK.

16th January 2008, 00:48	#1 (permalink)
Packhorse Custom Title Allowed! Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jan 2008 Location: Auckland New Zealand Posts: 103	Materials to avoid I hear that PVC should be avoided in the breathing loop as it may off gas some particularly nasty chemicals. And yet I see may homebuilds using PVC. What are you thoughts on PVC? Is there a type that is OK to use? What other materials should be avoided? Eg aluminium due to corrosive issues? What about materials for the counterlung? Is neoprene or urethane backed cordura OK? It would be a shame to build a safe rebreather only to die of lung cancer 5 years on. __________________ There are no stupid questions, but there are a LOT of inquisitive idiots.
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16th January 2008, 00:56	#2 (permalink)
OceanOpportunity for a world of water Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Dolphin Home Build Join Date: Nov 2006 Location: Providence, RI USA Posts: 544	Re: Materials to avoid aluminum is used in many of the commercial units, so is ok. anodized is better of course to reduce oxidation issues. PVC that is used for potable water is fine. actualy, most solid state PVC is incredibly stable. its the adhesives you have to worry about __________________ Michael Lombardi Oceans of Opportunity www.oceanopportunity.com Elected Director, Society for Human Performance in Extreme Environments MN'07, The Explorers Club Project Manager, Diving a Dream
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16th January 2008, 01:33	#3 (permalink)
cstmwrks The old ways still work. Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Sep 2006 Location: Boise Idaho Posts: 238	Re: Materials to avoid Quote: (Originally Posted by OceanOpportunity) most solid state PVC is incredibly stable. its the adhesives you have to worry about Thats why I took up the art of plastic welding with a heat gun and fill rod.. Just one more spendy item to buy to save money on that home build! __________________ Why you ask... well it's not like I have anything better to do.
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16th January 2008, 10:14	#4 (permalink)
lizardland Yak Current Rebreather/s: MK 15.X Home Build Other Rebreather/s: Classic Kiss Home Build Join Date: Mar 2005 Location: North... Posts: 1,302	Re: Materials to avoid Be careful with some sealants as they offgas a weak acid (i.e. vinegar) during curing. They take a surprising amount of time to fully cure and the vapours are irritating if you have them in a breathing loop. I found out the hard way __________________ Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you? www.westons-cider.co.uk Azerbaijani Association of Technical Divers Publicity Officer and Goat Wrangler
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16th January 2008, 11:38	#5 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,927	Re: Materials to avoid PVC, ABS with nasty plasticisers. Polyprop is supposed to be OK. __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
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