Anyone up to “no good” with design ideas?

AD_ward9 · 22nd September 2005, 17:32

Quote: (Originally Posted by Crazyduck)

What material are folks using for their scrubber cans?

Can’t use PVC, or certain plastics like delrin!

I was considering using harder plastics such as acrylic but that is questionable.

The best material is Grilamid. This comes in clear (TR90UV) and colour versions (LV 3H), is resistant to most solvents, tough. We have been testing it recently, and are very satisfied. At $6/kg the material cost is insignificant in a rebreather.

Uwatec use Grilamid for their latest dive computers, the ones with the overmoulded screens. It has very good properties for dive applications, in particular, it is resistant to UV and sea water, does not outgas nasty chemicals or smell, good fracture growth properties especially when glass loaded. It is one of very few plastics that come in a clear form that is resistant to solvents. Having it in two forms, clear and opaque coloured, makes over-mouldings bond and seal like a dream.

If you think about using acrylic, try some cheap nail varnish remover on it (containing acetone): just a wipe will be enough to reconsider. If people threw some at police riot shields, the shields would just crumble (so long as the police were not smoking, in which case there would be a different outcome).

On Delrin, I am aware the US Navy do not like it, but what is your problem with it? For all practical purposes, it works well, is easily machined, is a particularly strong plastic as well as tough, good UV resistance, water absorption at 0.7% is not bad, good fracture growth properties. I am interested in your reasons not to use it.

Cheers,
Alex

***caveseeker7*** · 22nd September 2005, 19:45

Quote: (Originally Posted by Crazyduck)

US Navy does not allow either material to be used because of off gasing into the breathing loop.

That is correct AFAIK.

Quote: (Originally Posted by bgpartri)

I just thought it was misinformation and wondered if it was documented.

Section 4.12.1 of Naval Sea Systems Command, DoD Handbook MIL-HDBK1036 prohibits toxic or hazhardous materials including "Polyvinil Chloride (PVC)".

If IIRC Delrin made the USN's shit list too. If it's really, really, really important I'll try to find it.

bgpartri · 22nd September 2005, 20:37

Quote: (Originally Posted by caveseeker7)

That is correct AFAIK.

Section 4.12.1 of Naval Sea Systems Command, DoD Handbook MIL-HDBK1036 prohibits toxic or hazhardous materials including "Polyvinil Chloride (PVC)".

If IIRC Delrin made the USN's shit list too. If it's really, really, really important I'll try to find it.

MIL HDBK-1036 seems to be a specification for Bachelor's quarters. I'm not sure how that applies to rebreathers. But anyway, I wasn't really wondering about PVC.

I'm much more interested in delrin, since it is so widely used in rebreathers.

I've heard about some molding processes that create parts that continue to off-gas, but I haven't heard that about machined delrin before.

onetime · 22nd September 2005, 21:11

Quote: (Originally Posted by bgpartri)

MIL HDBK-1036 seems to be a specification for Bachelor's quarters. I'm not sure how that applies to rebreathers. But anyway, I wasn't really wondering about PVC.

Quote: (Originally Posted by bgpartri)

I'm much more interested in delrin, since it is so widely used in rebreathers.

I've heard about some molding processes that create parts that continue to off-gas, but I haven't heard that about machined delrin before.

http://eiecomprod.shopforplastics.co...delrin570.html

When Delrin decomposes it gives off formaldehyde gas. May not be in significant quantities to be hazardous (MSD sheet shows no real hazard even if inhaling shavings) but not quite the gas we'd like to be breathing at depth.

***You're getting sleeeepy****

bgpartri · 22nd September 2005, 21:29

Quote: (Originally Posted by onetime)

not quite the gas we'd like to be breathing at depth.

Quote:

These substances do not present a respiration hazard unless the polymer is ground to a powder of respirable size and the dust is inhaled.

There are no known adverse health effects from exposure to "Delrin" polymer. However, if overheated, formaldehyde may be released.

Since I normally don't grind my rebreather to dust and inhale the dust, or burn parts of the loop underwater, the risk seems acceptable.

Did you know that if you ate ten times your weight in carrots that there is enough toxins in it to poison you?

***caveseeker7*** · 22nd September 2005, 21:35

Quote: (Originally Posted by bgpartri)

MIL HDBK-1036 seems to be a specification for Bachelor's quarters.

Freudian slip, I might just need a nap.

Make that 2036, Preparation of Electronic Equipment Specifications.

Googled PVC earlier, got "PVC products contain measurable quantities of dioxins, furans and PCBs: for some time after manufacture products offgas various chemical constituents and may release highly carginogenic Vinyl Chloride Monomer."

As for Delrin, we're probably thinking of the incident. Not sure if the molding process was the culprint.

Crazyduck · 22nd September 2005, 22:00

Quote: (Originally Posted by bgpartri)

Since I normally don't grind my rebreather to dust and inhale the dust, or burn parts of the loop underwater, the risk seems acceptable.

Man, I was told that Cocaine was expensive!

Holly Sh*t you want me to do WHAT? No way!

Then again, I work in Industrial Engineering- says nothing for my health.

bgpartri · 22nd September 2005, 22:36

Quote: (Originally Posted by caveseeker7)

Freudian slip, I might just need a nap.

Make that 2036, Preparation of Electronic Equipment Specifications.

Quote: (Originally Posted by MIL HDBK-2036)

2. This handbook is for guidance only. This handbook cannot be cited as a
requirement. If it is, the contractor does not have to comply.

Polyvinyl chloride (PVC), except when used for part leads

Hmmmm. But, as I said, I don't think PVC is used much in rebreathers is it?

And yes.....I do sit around home all day at my computer.

Andy M · 22nd September 2005, 22:38

Quote: (Originally Posted by Crazyduck)

Another point, Gore-Tex has a limited exposure rate to be truly waterproof and the material has to be treated after so long to maintain its properties. For example my North Face Gore-Tex jacket I need to wash it and retreat the material once a year.

Shiiiit... I didnt know this. Wondered why my 10 year old gore-tex jacket leaks like a sieve.

What do you treat it with? Never seen any gore-tex sealer in the camp shops round these parts.

dive2dive2000 · 22nd September 2005, 22:39

I thought that was tomatos

Quote: (Originally Posted by bgpartri)

Since I normally don't grind my rebreather to dust and inhale the dust, or burn parts of the loop underwater, the risk seems acceptable.

Did you know that if you ate ten times your weight in carrots that there is enough toxins in it to poison you?

22nd September 2005, 17:32	#31 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,862	Quote: (Originally Posted by Crazyduck) What material are folks using for their scrubber cans? Can’t use PVC, or certain plastics like delrin! I was considering using harder plastics such as acrylic but that is questionable. The best material is Grilamid. This comes in clear (TR90UV) and colour versions (LV 3H), is resistant to most solvents, tough. We have been testing it recently, and are very satisfied. At $6/kg the material cost is insignificant in a rebreather. Uwatec use Grilamid for their latest dive computers, the ones with the overmoulded screens. It has very good properties for dive applications, in particular, it is resistant to UV and sea water, does not outgas nasty chemicals or smell, good fracture growth properties especially when glass loaded. It is one of very few plastics that come in a clear form that is resistant to solvents. Having it in two forms, clear and opaque coloured, makes over-mouldings bond and seal like a dream. If you think about using acrylic, try some cheap nail varnish remover on it (containing acetone): just a wipe will be enough to reconsider. If people threw some at police riot shields, the shields would just crumble (so long as the police were not smoking, in which case there would be a different outcome). On Delrin, I am aware the US Navy do not like it, but what is your problem with it? For all practical purposes, it works well, is easily machined, is a particularly strong plastic as well as tough, good UV resistance, water absorption at 0.7% is not bad, good fracture growth properties. I am interested in your reasons not to use it. Cheers, Alex
(Offline)

22nd September 2005, 19:45	#32 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,451	PVC and Delrin Quote: (Originally Posted by Crazyduck) US Navy does not allow either material to be used because of off gasing into the breathing loop. That is correct AFAIK. Quote: (Originally Posted by bgpartri) I just thought it was misinformation and wondered if it was documented. Section 4.12.1 of Naval Sea Systems Command, DoD Handbook MIL-HDBK1036 prohibits toxic or hazhardous materials including "Polyvinil Chloride (PVC)". If IIRC Delrin made the USN's shit list too. If it's really, really, really important I'll try to find it. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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22nd September 2005, 20:37	#33 (permalink)
bgpartri Rebreather Zealot Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Sport Kiss Classic Kiss Titan Join Date: Apr 2005 Location: Vancouver, Canada Posts: 414	Quote: (Originally Posted by caveseeker7) That is correct AFAIK. Section 4.12.1 of Naval Sea Systems Command, DoD Handbook MIL-HDBK1036 prohibits toxic or hazhardous materials including "Polyvinil Chloride (PVC)". If IIRC Delrin made the USN's shit list too. If it's really, really, really important I'll try to find it. MIL HDBK-1036 seems to be a specification for Bachelor's quarters. I'm not sure how that applies to rebreathers. But anyway, I wasn't really wondering about PVC. I'm much more interested in delrin, since it is so widely used in rebreathers. I've heard about some molding processes that create parts that continue to off-gas, but I haven't heard that about machined delrin before. __________________ http://www.shearwaterresearch.com Good judgment comes from experience. Experience comes from bad judgment.
(Offline)

22nd September 2005, 21:11	#34 (permalink)
onetime Classic KISSer #138 Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: US, NJ Posts: 673	Quote: (Originally Posted by bgpartri) MIL HDBK-1036 seems to be a specification for Bachelor's quarters. I'm not sure how that applies to rebreathers. But anyway, I wasn't really wondering about PVC. Quote: (Originally Posted by bgpartri) I'm much more interested in delrin, since it is so widely used in rebreathers. I've heard about some molding processes that create parts that continue to off-gas, but I haven't heard that about machined delrin before. http://eiecomprod.shopforplastics.co...delrin570.html When Delrin decomposes it gives off formaldehyde gas. May not be in significant quantities to be hazardous (MSD sheet shows no real hazard even if inhaling shavings) but not quite the gas we'd like to be breathing at depth. *You're getting sleeeepy**
(Offline)

22nd September 2005, 21:29	#35 (permalink)
bgpartri Rebreather Zealot Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Sport Kiss Classic Kiss Titan Join Date: Apr 2005 Location: Vancouver, Canada Posts: 414	Quote: (Originally Posted by onetime) not quite the gas we'd like to be breathing at depth. Quote: These substances do not present a respiration hazard unless the polymer is ground to a powder of respirable size and the dust is inhaled. There are no known adverse health effects from exposure to "Delrin" polymer. However, if overheated, formaldehyde may be released. Since I normally don't grind my rebreather to dust and inhale the dust, or burn parts of the loop underwater, the risk seems acceptable. Did you know that if you ate ten times your weight in carrots that there is enough toxins in it to poison you? __________________ http://www.shearwaterresearch.com Good judgment comes from experience. Experience comes from bad judgment.
(Offline)

22nd September 2005, 21:35	#36 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,451	Quote: (Originally Posted by bgpartri) MIL HDBK-1036 seems to be a specification for Bachelor's quarters. Freudian slip, I might just need a nap. Make that 2036, Preparation of Electronic Equipment Specifications. Googled PVC earlier, got "PVC products contain measurable quantities of dioxins, furans and PCBs: for some time after manufacture products offgas various chemical constituents and may release highly carginogenic Vinyl Chloride Monomer." As for Delrin, we're probably thinking of the incident. Not sure if the molding process was the culprint. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
(Offline)

22nd September 2005, 22:00	#37 (permalink)
Crazyduck Underwater Mechanic Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2005 Location: TEXAS, Dallas/ Ft.Worth Posts: 711	Quote: (Originally Posted by bgpartri) Since I normally don't grind my rebreather to dust and inhale the dust, or burn parts of the loop underwater, the risk seems acceptable. Man, I was told that Cocaine was expensive! Holly Sh*t you want me to do WHAT? No way! Then again, I work in Industrial Engineering- says nothing for my health.
(Offline)

22nd September 2005, 22:36	#38 (permalink)
bgpartri Rebreather Zealot Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Sport Kiss Classic Kiss Titan Join Date: Apr 2005 Location: Vancouver, Canada Posts: 414	Quote: (Originally Posted by caveseeker7) Freudian slip, I might just need a nap. Make that 2036, Preparation of Electronic Equipment Specifications. Quote: (Originally Posted by MIL HDBK-2036) 2. This handbook is for guidance only. This handbook cannot be cited as a requirement. If it is, the contractor does not have to comply. Polyvinyl chloride (PVC), except when used for part leads Hmmmm. But, as I said, I don't think PVC is used much in rebreathers is it? And yes.....I do sit around home all day at my computer. __________________ http://www.shearwaterresearch.com Good judgment comes from experience. Experience comes from bad judgment.
(Offline)

22nd September 2005, 22:38	#39 (permalink)
Andy M Dude Current Rebreather/s: Home Build Other Rebreather/s: Sport Kiss Home Build Join Date: Mar 2005 Location: Cambridge, UK Posts: 422	Quote: (Originally Posted by Crazyduck) Another point, Gore-Tex has a limited exposure rate to be truly waterproof and the material has to be treated after so long to maintain its properties. For example my North Face Gore-Tex jacket I need to wash it and retreat the material once a year. Shiiiit... I didnt know this. Wondered why my 10 year old gore-tex jacket leaks like a sieve. What do you treat it with? Never seen any gore-tex sealer in the camp shops round these parts. __________________ Know your PO2 at all times
(Offline)

22nd September 2005, 22:39	#40 (permalink)
dive2dive2000 PRISM DIVER & LUVIN IT! Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Long Island, NY Posts: 788	I thought that was tomatos Quote: (Originally Posted by bgpartri) Since I normally don't grind my rebreather to dust and inhale the dust, or burn parts of the loop underwater, the risk seems acceptable. Did you know that if you ate ten times your weight in carrots that there is enough toxins in it to poison you? __________________ Safe Diving, Martin
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