How many pounds of CO2 in a 10-pound CO2 tank?

It seems like the answer should be obvious, but today I brought my new 10-pound tank to the LHBS and had it filled. I watched the guy weigh it and it came to a little over 6 pounds (verified by my home scale) and that's all they charged me for, but I was wondering if I should take it to a welding shop in the future as I'd like to minimize my refill trips.

10 lbs of co2. some places won't fill them much more than that

The problem comes in how they fill it...

If all they have are CO2 tanks you won't get a full tank. They will hook the two up and equalize the pressure. How full the big tank is will determine how much you get. One thing that will help that is if they put in a pound then purge it or discharge any remaining CO2 if it is there. This rapidly chills the tank then when they do the actual fill the tank will take more due to the temperature it is at.

The best way to get a fill though is to go to a real fill station like a welding supply shop. They will use a pump move the CO2 into your tank, not just tank pressure. I also prefer them because they tend to know a hell of a lot more about gas and CO2 tanks than your average LHBS, keg shop, paint ball, aquarium, etc place.

TomSD said:

One thing that will help that is if they put in a pound then purge it or discharge any remaining CO2 if it is there. This rapidly chills the tank then when they do the actual fill the tank will take more due to the temperature it is at.

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The tank was filled in a back room so I couldn't observe the procedure, all I saw was the weighing. It was ice cold when handed back to me.

I'll probably use a welding shop in the future because I want to minimize refill trips.

LHBS are the most expensive place you can find to have a CO2 tank filled. How much did he charge? I pay $17 for a 20 lb swap.

$2.50/lb. I'd rather not do a swap because it's a new tank, but I'll call around and see what other places charge.

Man, Co2 bottle swap here (Tallahassee FL) is $30 for a 5lb bottle.

Refill from a fire extinguisher place is $21 and they only fill 1 day a week.....I need to find a welding shop and see the price.,

cruckin78 said:

Man, Co2 bottle swap here (Tallahassee FL) is $30 for a 5lb bottle.

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That's what, 5 times as expensive as propane? A gas that we exhale shouldn't cost more than a gas that comes from deep inside the Earth's crust.

P.S. My former in-laws live in Monticello. Nice place.

I do the Co2 swap thing. Our welding supplier charges 15 bucks for a 10lb bottle. It sucked giving up my shiny, new, unused tank but they will only do swaps on smaller tanks. To refill you need a 50lb minimum, I think.

to fill mine local,its $20.00 for a 5lb. tank at the gun shop. they kinda tripped out the first time I showed up with it. they are set up for paintball. and they acted like I was getting over on them. until I told them I knew that I could swap out a 20lb tank for $20.00 at the place they get the CO2 from. I need to find an old rusty 20lb. tank to swap. the place that dose the swap will only let you in if you have a tank. I told them I'd pay a deposit for the first tank and the old man said, we dont do that. I had a $100.00 bill in hand and he still would'nt budge. "you have to have an empty tank" I can drive into the city and fill it for about half that price. should have never got the new Alum. tank. but it looks way better than an old rusty one.

Derp said:

P.S. My former in-laws live in Monticello. Nice place.

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I actually live in Monticello but no one normally knows where it's at LOL

You should be getting 10lbs of liquid CO2 in a 10lb tank.

Is this one of those questions like ..."which is heavier a ton of feathers or a ton of bricks"?

I was only charged $13 for a 20lb co2 tank swap, I got a deal apparently.

Finding a welding supply shop is the best bet. Where I go its about $1.50/lb with tax and I get to keep my own tank.