Homebrewers Association | AHA Forum

General Category => Kegging and Bottling => Topic started by: dwhite55 on December 21, 2012, 03:59:45 AM

Title: co2 tank filling
Post by: dwhite55 on December 21, 2012, 03:59:45 AM
Is it safe to assume that a 5 # co2 tank should weigh 5# more when full than empty?
Every time I have gotten mine filled it is less than 3 #s. Today I had it filled and it weighs 1# 14.4 oz more than when it was empty.

I questioned the guy before and he gave me some BS about it may heat up and expand so they can't fill them to 5#s.
Title: Re: co2 tank filling
Post by: ultravista on December 21, 2012, 05:40:34 AM
I fill my 10# tank up at a local fire supression place and they weigh the empty bottle and add 10 pounds. I've watched them do it. It may be a little less than 10 but it's in the ballpark.

While the gas is cold, I doubt you're loosing 4 pounds.
Title: Re: co2 tank filling
Post by: Slowbrew on December 21, 2012, 01:16:12 PM
A 5lb tank should hold 5lbs of CO2.  The gas is under enough pressure to become a liquid.  I don't want to be harsh but he either doesn't know what he is talking about or is intentionally lying to pad his profits.   Hopefully you can find a different supplier.  I use a fire equipment company for my refills.  Look for "carbonic" suppliers in you area.

Paul
Title: Re: co2 tank filling
Post by: dak0415 on December 21, 2012, 01:20:04 PM
I questioned the guy before and he gave me some BS about it may heat up and expand so they can't fill them to 5#s.
Its like Blue Rhino only putting 15# in a 20# propane tank "for safety".  When my local guy fills my propane tank, its 20# heavier.
Sounds to me like you need to find another place to get your tank filled.  I just swap my 5# tank out at Airgas, but I have them refill the 15# tank.
Title: Re: co2 tank filling
Post by: dak0415 on December 21, 2012, 01:25:35 PM
A 5lb tank should hold 5lbs of CO2.

+1.  That's why the call it a 5# tank :)
Title: Re: co2 tank filling
Post by: ultravista on December 21, 2012, 03:34:06 PM
Check if you have SimplexGrinnell in your neck of the woods. They fill my tanks here in Vegas. Airgas is another place.
Title: Re: co2 tank filling
Post by: anje on December 21, 2012, 05:00:06 PM
I questioned the guy before and he gave me some BS about it may heat up and expand so they can't fill them to 5#s.
Temperature change isn't going to affect weight/mass.
Title: Re: co2 tank filling
Post by: dwhite55 on December 21, 2012, 05:32:42 PM
Thanks for all the input. It is exactly what I assumed. I questioned the guy this morning. he had all kinds of excuses. I have found a new supplier. He's a little further away, but for a full tank it's worth it.
Thanks again,
dwhite55
Title: Re: co2 tank filling
Post by: hubie on December 21, 2012, 06:17:36 PM

Temperature change isn't going to affect weight/mass.

Well, sure, maybe for non-relativistic physics ...

By the way, do places that fill CO2 bottles generally also deal with propane?  Most of the places I see for propane (gas stations, big box stores, grocery stores) all have the Blue Rhino setup and I'd like to see what other options I have.
Title: Re: co2 tank filling
Post by: Jimmy K on December 21, 2012, 06:19:34 PM
I questioned the guy before and he gave me some BS about it may heat up and expand so they can't fill them to 5#s.
Temperature change isn't going to affect weight/mass.
It would affect pressure which is the real concern with a tank. But still, 2lbs in a 5lb tank would be 60% headspace - overkill. I would think a 5lb tank is certified to hold 5lbs of CO2 and still have space for expansion, but I don't know the specifics of tank certification.
Title: Re: co2 tank filling
Post by: Jimmy K on December 21, 2012, 06:22:01 PM
By the way, do places that fill CO2 bottles generally also deal with propane?  Most of the places I see for propane (gas stations, big box stores, grocery stores) all have the Blue Rhino setup and I'd like to see what other options I have.
A compressed gas supply company might do both, but otherwise its probably one or the other. Look for places that sell propane for heating, they usually fill BBQ tanks too.
Title: Re: co2 tank filling
Post by: Jimmy K on December 21, 2012, 06:53:30 PM
Of course, if the tank isn't completely empty when you bring it in, that may be a different story.
Title: Re: co2 tank filling
Post by: Slowbrew on December 22, 2012, 02:04:20 PM
I don't think there are requirements that say a business can't do both but here in Des Moines they seem to devide alone fuel and non-fuel lines.  I can find dive shops that fill CO2 and oxygen, carbonic suppliers that just fill CO2, fuel companies for just LP but I haven't found anyone who does all 3.  At a retail level at least.

Paul
Title: Re: co2 tank filling
Post by: jimrod on December 31, 2012, 06:27:27 PM
You should call the dept of weights and measures in your state, they calibrate and monitor for accuracy on all devices.  Maybe the state official can set him straight. 

OR just pay him by the pound like my propane guy, and not per tank.

My local brew store sets the CO2 tank on a scale, zeros the scale, then fills the tank to 5 lbs. (and only charges $10)
Title: Re: co2 tank filling
Post by: gmac on December 31, 2012, 06:32:31 PM
Sounds to me like he doesn't know how to fill a tank.  My local fire guy fills mine and I think he probably wastes as much as he puts in because he says the tank has to be cold in order to fill properly so he fills (puts gas ins) and purges my tank 3 or 4 times until it's frosty and then fills it.  I think if you just hook up a warm tank you can't get 5 lbs in due to the expansion or something. 
Either way you're getting ripped off.
Title: Re: co2 tank filling
Post by: nateo on December 31, 2012, 08:06:29 PM
We fill propane tanks by weight. I don't know if it's the same, but if the tank was improperly purged (there's air in there) that will throw off the weight, and limit the amount of propane that will fit in the tank.  If it's really hot outside (100*F+), it's hard to fill a propane tank 100% full. It makes total sense that your CO2 tank won't hold 5lbs if it's hot. Unless they cycle CO2 to cool it off like gmac described, it just won't all fit in there.
Title: Re: co2 tank filling
Post by: Jimmy K on December 31, 2012, 09:11:01 PM
You should call the dept of weights and measures in your state, they calibrate and monitor for accuracy on all devices.  Maybe the state official can set him straight. 
Good idea. They may regulate it and they surely can tell you what an acceptable fill level is for your tank.
Title: Re: co2 tank filling
Post by: nateo on December 31, 2012, 09:18:36 PM
Someone called weights and measures on us once, because of this problem with a short fill. They came out, tested our scale, said it was fine, and left. They come out every year to test our equipment anyway (scale and the flow meter for RVs). It's not likely that the scale is the problem, or that you'll do anything but waste a bureaucrat's time.

I'd call the BBB if you think you're getting ripped off.

(We only charge by the pound, BTW, so we only charged him for the short-fill amount, but he was still pissed).
Title: Re: co2 tank filling
Post by: Jimmy K on December 31, 2012, 09:24:57 PM
In Delaware they do far more than scales. They'll test almost anything in a pre-measured package to make sure it contains what the measurement says.
 
But it might be easier to get the tank filled at a place you KNOW won't rip you off (like a pressurized gas distributor that deals with lots of commercial customers. Weight it after filling and then you know what the other guy should be filling to. If they short, tell them and go elsewhere.
Title: Re: co2 tank filling
Post by: nateo on December 31, 2012, 09:41:57 PM
I think if you just hook up a warm tank you can't get 5 lbs in due to the expansion or something. 

If CO2 is anything like propane, this is true. Our equipment has a pressure safety mechanism. Hot gases expand. If the tank is hot, the propane will expand, tripping the pressure mechanism on the filling device before the desired weight of gas is in the tank. At that point, the machine can't put any more propane in the tank.
Title: Re: co2 tank filling
Post by: HobsonDrake on January 01, 2013, 12:36:36 AM
I like my AirGas place. What I like best is they don't fill the tank, they trade it out for a full one. This insures that the tank is within DOT testing and no waiting. I think I paid $13-$14 for my last fill/tank.
Title: Re: co2 tank filling
Post by: realbeerguy on January 01, 2013, 04:37:06 AM
I like my AirGas place. What I like best is they don't fill the tank, they trade it out for a full one. This insures that the tank is within DOT testing and no waiting. I think I paid $13-$14 for my last fill/tank.

Same here with Airgas
Title: Re: co2 tank filling
Post by: tschmidlin on January 01, 2013, 11:43:47 PM
We fill propane tanks by weight.
Is that a common thing in MO?  I've never seen that, all of the places here and any other place I've gotten a tank filled charge by the gallon.

I swap all of my CO2 tanks, I really prefer it.  Very fast and easy.
Title: Re: co2 tank filling
Post by: hopfenundmalz on January 02, 2013, 12:04:04 AM
We fill propane tanks by weight.
Is that a common thing in MO?  I've never seen that, all of the places here and any other place I've gotten a tank filled charge by the gallon.

I swap all of my CO2 tanks, I really prefer it.  Very fast and easy.

In MI it is by weight. The tank goes on a scale, they set it for the tare and fill weight from the table they have posted on the filling shed wall.

Edit - there are few that charge by the gallon, but those are more expensive in my limited experience with that fill charge schedule.
Title: Re: co2 tank filling
Post by: tschmidlin on January 02, 2013, 03:59:08 AM
Edit - there are few that charge by the gallon, but those are more expensive in my limited experience with that fill charge schedule.
Any idea why it would be more expensive?
Title: Re: co2 tank filling
Post by: hopfenundmalz on January 02, 2013, 01:06:05 PM
Edit - there are few that charge by the gallon, but those are more expensive in my limited experience with that fill charge schedule.
Any idea why it would be more expensive?

Not really, one is a hardware store with a very large bulk tank they fill from by the full fill, the other has a smaller bulk tank and charges by the gallon. The LP supplier was different for them, which might be part of it. Small sample size here.
Title: Re: co2 tank filling
Post by: tschmidlin on January 02, 2013, 05:28:18 PM
Edit - there are few that charge by the gallon, but those are more expensive in my limited experience with that fill charge schedule.
Any idea why it would be more expensive?

Not really, one is a hardware store with a very large bulk tank they fill from by the full fill, the other has a smaller bulk tank and charges by the gallon. The LP supplier was different for them, which might be part of it. Small sample size here.
I found the place that fills the tanks for the local gas stations and other LP sellers - it doesn't look like the kind of place that would deal with a random guy showing up with a 20# tank, but they do :)  It is way cheaper from them than from any of the resellers, and about a block from the CO2 place.  Although it's very convenient anyway, I'm within 0.5 miles of there pretty much twice a day.
Title: Re: co2 tank filling
Post by: BrewArk on January 02, 2013, 05:41:14 PM
I've done both.  A local welding shop will trade the tank.  The homebrew shop fills by the pound.  I'm not sure who they wholesale with.

The homebrew shop requires that you leave the tank overnight.  They put it in their freezer so that they have it real cold and can fit the gas into the tank.  If it is an old tank, they'll send it out to be hydro-tested.

The owner quoted me one price (w/the hydro-test including the CO2) and the cellar-boy adding the cost of the CO2 to the hydro-test price.  After informing him that the boss had quoted me differently, he gave me the lower price.

I get my propane refilled @ a local gas station.  That's much cheaper than the tank exchanges because you get a full tank.

When the tank approaches the need for retesting, I exchange it.  I suppose it's gaming the system, but I'm not going to loose sleep over it.

It wasn't cheap, I paid over $75 for three tanks (a 5,a 10, and a 20#), but now I have enough CO2 to last a while.

The local hardware store fills paintball tanks for $7.  A handy profit for them.
Title: Re: co2 tank filling
Post by: safi on January 10, 2013, 03:09:28 PM
so i recently picked up a 10lbs tank from my local homebrew store, and payed $21 for a fill, only to hook it up and find the next day after carbonating the regulator has dropped to the order soon marking, which stumbled me, because i tested for any leaks before storing it in a cold environment (garage) should i go back and ask them to fill it back up?
Title: Re: co2 tank filling
Post by: hopfenundmalz on January 10, 2013, 03:16:36 PM
so i recently picked up a 10lbs tank from my local homebrew store, and payed $21 for a fill, only to hook it up and find the next day after carbonating the regulator has dropped to the order soon marking, which stumbled me, because i tested for any leaks before storing it in a cold environment (garage) should i go back and ask them to fill it back up?

The pressure drops if cold, you didn't say how cold your garage is. You can warm it up and see if the temp brings the pressure up.
Title: Re: co2 tank filling
Post by: blatz on January 10, 2013, 03:17:48 PM
so i recently picked up a 10lbs tank from my local homebrew store, and payed $21 for a fill, only to hook it up and find the next day after carbonating the regulator has dropped to the order soon marking, which stumbled me, because i tested for any leaks before storing it in a cold environment (garage) should i go back and ask them to fill it back up?

you are aware that your tank high pressure gauge is going to drop to ~500 PSI when it is stored below 40df even when it is completely full, right?

this chart is a keeper:

Quote
F   psi
----------------
80   969
70   853
60   747
50   652
40   560
30   491

C   Bar   kPa
----------------
30   72   7184
25   65   6471
20   57   5715
15   51   5066
10   45   4497
 5   40   3959
 0   36   3612
Title: Re: co2 tank filling
Post by: safi on January 10, 2013, 03:38:35 PM
so i recently picked up a 10lbs tank from my local homebrew store, and payed $21 for a fill, only to hook it up and find the next day after carbonating the regulator has dropped to the order soon marking, which stumbled me, because i tested for any leaks before storing it in a cold environment (garage) should i go back and ask them to fill it back up?

you are aware that your tank high pressure gauge is going to drop to ~500 PSI when it is stored below 40df even when it is completely full, right?

this chart is a keeper:

Quote
F   psi
----------------
80   969
70   853
60   747
50   652
40   560
30   491

C   Bar   kPa
----------------
30   72   7184
25   65   6471
20   57   5715
15   51   5066
10   45   4497
 5   40   3959
 0   36   3612
i was unaware of that, i feel dumb now, thank you
Title: Re: co2 tank filling
Post by: blatz on January 10, 2013, 03:51:01 PM
i was unaware of that, i feel dumb now, thank you

wasn't trying to make you feel dumb - perhaps I should have phrased that a bit better - not my intent.

hey -you didn't know - you asked, and now you do!
Title: Re: co2 tank filling
Post by: morticaixavier on January 10, 2013, 03:52:49 PM
i was unaware of that, i feel dumb now, thank you

wasn't trying to make you feel dumb - perhaps I should have phrased that a bit better - not my intent.

hey -you didn't know - you asked, and now you do!

to quote G.I. Joe, "Now you know, and Knowing is half the battle"
Title: Re: co2 tank filling
Post by: blatz on January 10, 2013, 03:55:09 PM
one other good thing to do, if you have a scale that will weigh something that heavy is to weigh the bottle after filling (tare weight is required to be printed on the bottle) and then you know how many pounds you got and can keep track of how much is left in it.  also, perhaps weigh it with the regulator attached and then you can keep track of how much CO2 you are using.
Title: Re: co2 tank filling
Post by: dak0415 on January 10, 2013, 03:57:43 PM
Weigh it! (without the regulator)  The tare weight should be on the tank.

Oops - make that +1, what Paul just said!
Title: Re: co2 tank filling
Post by: safi on January 11, 2013, 01:00:57 PM
thanks a lot, well its a bit too late to weigh it now, as ive already used it, but definitely good news for the next refill