CO2 half-life?
 

hey all... i have only previously ridden around campus (2 miles max) so it was never a big deal to not carry around flat-fixing gear. but to fend off winter break poundage i decided to go on my first lengthy ride, and bought the necessary emergency stuff (levers, tube, CO2 inflator). in order to save limited pocket space, i installed the cartridge in the inflator... akin to a balloon, will the cartridge slowly start to "deflate"? if, by the grace of your deity of choice, i dont get a flat for, lets say, 6 months, can i assume that the cartridge will be able to get my tube up to a decent pressure? i just dont want to be fixing a flat and end up with a tire at 20psi.

Yes, your cartridge will eventually lose most pressure over time.....usually within days. I store my cartridge upside down in the inflator. I had to drill a hole at the very bottom of the inflator housing large enough for the cartridge nipple to poke out of for this to work. I also carry a loose second cartridge.

Yes the CO2 will go down fast. You do pay a price for only carrying CO2, I hav never wanted to take that price, chance with CO2. How far you are going and whether you have a cell phone, etc will determine your choice in how and what you carry.

Oh ya... CO2 is not nuclear and has no "half life". Half life assumes breakdown and that is not what normal CO2 does, it effuses through the tube with time...

right... i just sorta meant that the usable CO2 will diminish over time. but anyway, thanks. i suppose i'll try the inverted technique mentioned above.

Just don't pierce the cartridge until you're ready to use it.

Maybe I learned wrong as a Chemistry major but I thought all atoms/molecules decayed given enough time...

i think you are thinking about "hydrogen burning"... there is a great paper on it in the literature, but in short it states that there is always some fussion occuring (two hydrogens form a helium; two heliums form a beryllium; and ect.). This fussion will continue until some isotope (something like lead-208 {double magic number} or iron-something) and that all isotope heavier than this isotope will decay (via alpha, beta, fission, ect) to reach this magic isotope

mind you that the time span for this is infinite and it is just a theory

I totally eat stuff up like that.

I listened to the audio book of "The Andromeda Strain" a few months ago and one thing that was intriguing was these doctors and scientists were trying to prove that something was alive. One of them said that a black piece of fabric was living because it converted energy. One of the more eccentric ones said that a rock was alive but we couldn't comprend it because our understanding of time was so short. To the rock we were unequaly as thought to be alive because we only existed in a fraction of a second in it's timespan. :eek: Some good stuff in that book..

that is a great book, the movie is not as good, they tried very hard, but left out all the different ways that they had to become cleaner than they previously were to go to the next level
other books by critton (sp?) are really good, sphere and congo(better than the movie, like all books) are great also

This is the best advice. I'm surprised no one else had mentioned it yet. If you're using non-threaded CO2, start buying them at Wal-mart in the bb-pellet gun area of sporting goods. Way cheaper than you'll find anywhere.

The co2 inflators do not work well, or at all in 20 degree weather. They get so cold the nozzle freezes up and it will not fill. It helps if you put it under your coat for a while first and warm it up, then fill it up right away without too much exposure to the cold. Also in the cold there is a lot less pressure in the cartridge. a lot less. If you need two carts to fill your tire in the summer it won't work if it's cold. If it's important to you, carry a pump in the winter. The cartridges will lose pressure in a year. Just get now ones every season. I like the way they work in the summer

Do they have threaded cartridges? I got a threaded microflate mini co2 inflator because its so damn tiny.. Should I have gotten a non-threaded device?

What are you doing riding in 20 degree weather :eek:

I would not survive with CO2... they would cost me too much,... just got another flat today :(

As to the chemistry question... I too am a chemistry major (as also a phyisics major)

All atoms have unstable isotopes, nuclotides do decay with time, depending on the half life. Generally we think that molcules that follow the line of stability (nuclotide chart) do not or decay very very slowly (as if a half life of 200 years+ is not slow). We would not see the decay of stable CO2 molecule in our lifetimes if never.

For information, half life does not necessarily deal with something nuclear:

http://www.ozoneservices.com/glossary/h/halflife.htm

being cool? .......sorry :o

studded tires and ski clothing make snow and ice fun on an MTB.

I don't think the threaded cartridges are at Wal mart or places where bb guns are sold, I looked for them.

I use my non threaded inflator on group rides or to change tires pressures, because the non threaded cartridges are so much less.

Hmm. I may have to return my threaded type and get non-threaded...

I tired to find the threaded ones for less on the net and everywhere I could, I never did. I buy the non threaded by the box at a Dept. Store. They come out to about 55 cents a piece. I think the threaded 12 gram equivalent is maybe 2 or 3 bucks each? The non threaded cartridge holder is a little bigger, but I don't mind. That way I don't mind using them. Sometimes I ride on the pavement for 10 miles to get to off road riding. I put my pressure down to about 35 for some off roading. Then one 12 gram cartridge for each tire, I can bring the tires back up to about 65 for the pavement ride home. For $1.00 or $2.00 with a friend. It's very handy.

WARNING ON CO2 USE!

It will add approx 7grams of weight *to your ride over just air.


* base on a 700 23 tire at 70 degress

pv=nrt ;)

Can I drill holes in the CO2 ?
;)

so should I than carry helium? Or be brave and carry hydrogen...

So I guess the questions is what it lighter 7g of CO2 in the wheels, an empty CO2 cartridge and a CO2 pump, or a frame pump? If you are worried about weight that is... I am more worried about getting home if I have a flat than if my bike is 7 grams heavier

You could try a more compact CO2 inflater. My LBS hooked me up w/ one that is very small. The cartridge doesn't fit inside of a housing. It just screws into one end of the inflater and the other end of the inflater goes over the tube's valve. The inflater is very small - about 3/8 inch dia & maybe 1 1/2 inch long.

I think we have the same thing. I picked it out because it was TINY but now I realize I will be spending a l ot more for threaded cartidges...