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H2 production membranes
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jjb2888 Offline
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Post: #21
RE: H2 production membranes
Terry_Dodson Wrote:
hygear Wrote:
Terry_Dodson Wrote:Has anyone thought about Kevlar cloth?

Got any specs on the kevlar?

I found this and thought it sounded good:

Kevlar was developed in the early 1960's by Dupont. Assuming the same weight, Kevlar is literally five times stronger than steel. Kevlar fibers also have 43 percent less density than fiberglass. Originally developed to replace steel tire belts, it is an aramid with high strength and notable heat resistance. Kevlar's biggest weakness is its lack of compressive strength.
Why is Kevlar so useful for composites? A few reasons:

Thermal properties
Highly flame resistant
Can handle temperatures to 320 degrees F for extended periods with ease
Significantly lighter than even E-glass
Will not melt (at 800 degress F it begins to decompose

Kevlar sounds good, just don't know the cost also Goretx could work.
09-09-2008 04:00 PM
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staugur Offline
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Post: #22
RE: H2 production membranes
what we are looking for is a cheap version of nafion.It has to allow the flow or transfer of electricity(electrons)but stop gas transfer.there's several versions available but the best price I have seen is going to add about $300 to a 4x6"plate size,seven series cell. Right now I have decided to build a single cell test unit with a slide in/out divider and test some stupid stuff.Celgard is advertising it's product all over the place but as yet I can't find a specific price.When you consider how cheap batteries are to buy,car batteries that is,they must be full of the stuff.Perhaps the cheap way out is to buy a dry one and break it up to get at the stuff.Apparently aircraft batteries are even better as they are ni-cad and use a better product.The last one I bought for my plane was $175 so if I can bust one up and get a couple of square feet out of it I'm a happy boy.Anyway going to try and call them tomorrow and give the tech departement some bullshit and see if they are prepared to send out some samples.Incidentally .after ploughing through their website their triple layer polyurethane barrier has a 17 micron weave.Tap plastics has a 1 micron nylon mesh but it's not cheap.$100 for 5 square feet.Keep you posted.
09-09-2008 04:21 PM
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cmac Offline
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Post: #23
RE: H2 production membranes
asbestos
09-09-2008 05:37 PM
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staugur Offline
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Post: #24
RE: H2 production membranes
cmac Wrote:asbestos

If that's the simple answer then you're a millionaire.How are you going to bring a product to the marketplace containing asbestos? Sheesh! If that's your best suggestion i think you should stop posting.
09-09-2008 06:53 PM
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finallyME Offline
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Post: #25
RE: H2 production membranes
A roll of celgard is around $500. But, there is a lot in a roll. I tried to see how much was on a roll, but it isn't written on the rolls, and I couldn't find it on their website. If you want to guess, then the center cardboard on the roll has a 3 inch approximate diameter. The outside diameter is probably 7 inches ( I guess I should actually measure it, ,but then I could just call Big Grin ). It was 4 inches tall. Celgard is pretty much polypropylene that is porous. Terry, celgard was developed for the purpose of letting electrons through, but still providing a barrier, mostly for harsh chemicals found in batteries. A good solution might be for someone to buy a roll and then sell small parts of it to the rest of the people who want some. I plan on testing with it and using it as a base to compare other materials. Here are some other porous membranes that I can think of:

Tyvek, Gortex, Porex, Sympatex, Pall membranes, Frogg Toggs, etc. Basically, if it says waterproof/breathable, then it is porous. WP/B fabrics have larger pores than celgard, but much smaller ones than any cloth, fiberglass weave, kevlar weave, or nomex weave. Celgard is also cheaper than kevlar or nomex.

My vehicles:
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09-09-2008 07:36 PM
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staugur Offline
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Post: #26
RE: H production membranes
finally ME Wrote:A roll of cellared is around $500. But, there is a lot in a roll. I tried to see how much was on a roll, but it isn't written on the rolls, and I couldn't find it on their website. If you want to guess, then the centre cardboard on the roll has a 3 inch approximate diameter. The outside diameter is probably 7 inches ( I guess I should actually measure it, ,but then I could just call Big Grin ). It was 4 inches tall. Cellared is pretty much polypropylene that is porous. Terry, cellared was developed for the purpose of letting electrons through, but still providing a barrier, mostly for harsh chemicals found in batteries. A good solution might be for someone to buy a roll and then sell small parts of it to the rest of the people who want some. I plan on testing with it and using it as a base to compare other materials. Here are some other porous membranes that I can think of:

Tyke, Cortex, Pyrex, Semtex, Pall membranes, Frog Togs, etc. Basically, if it says waterproof/breathable, then it is porous. WP/B fabrics have larger pores than cellared, but much smaller ones than any cloth, Fiberglas weave, Kevlar weave, or Mex weave. Cellared is also cheaper than Kevlar or Mex.

Well your heads working in the right direction.I'm planning on using a really strong solution of pot-28%weight and I'm not sure it wouldn't eat up some of your suggestions.Funnily enough i also thought about gortex-breathable fabric right.If i can find something that works i don't have a problem buying in bulk and selling small quantities to you guys.The nylon meshes that are sold by small parts start at dollars per square inch if you buy a 12 inch square but a roll at $1300 comes down to cents per square.I'll hit Celgard in the morning and see what I can find out.Better to start with something that lives in acid/alkali than something that may disintegrate.
(This post was last modified: 09-09-2008 07:55 PM by staugur.)
09-09-2008 07:54 PM
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visek Offline
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Post: #27
RE: H2 production membranes
McMaster sells various meshes of ss and nylon, etc. You aren't working at a molecular level...just a "bubble" level. A fairly fine but open weave mesh would do it? Has to be electrically "transparent"?
09-10-2008 12:35 AM
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jjb2888 Offline
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Post: #28
RE: H2 production membranes
staugur Wrote:
cmac Wrote:asbestos

If that's the simple answer then you're a millionaire.How are you going to bring a product to the marketplace containing asbestos? Sheesh! If that's your best suggestion i think you should stop posting.

Asbestos used to be used before its danger was exposed. After that it was replaced with fiberglass before the new polymers were developed.
09-10-2008 04:13 AM
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finallyME Offline
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Post: #29
RE: H2 production membranes
visek Wrote:McMaster sells various meshes of ss and nylon, etc. You aren't working at a molecular level...just a "bubble" level. A fairly fine but open weave mesh would do it? Has to be electrically "transparent"?


You are right, but if you use a mesh, then it limits the distance the two electrodes can be (ie, big mesh equals big electrode spacing distance). This cuts on efficiency and makes your cell bigger. Hydrodine's design uses no mesh, just holes. But, his electrode spacing is great enough. Anyways, anything that has holes bigger than electrons should be electrically transparent, even more so if water molecules can touch each other on each side, even if the water can't pass through, electrons can.

My vehicles:
2002 Saturn SL2 4 banger
2006 Chrysler Town and Country

You can kill two birds with one stone, but you can't kill one stone with two birds. Big Grin
09-10-2008 05:30 AM
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howiemandel Offline
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Post: #30
RE: H2 production membranes
A link that might be of intrest.

http://www1.eere.energy.gov/hydrogenandf...s_talk.pdf
09-10-2008 05:31 AM
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