Five pound CO2 tank - Is it full?

[Chorgey]

I just had my 5 lb. CO2 tank filled at my LHBS and (to me), something doesn't seem right. The tare weight is 7.62 lbs., after taking it home, I weighed it and it's 10.33 lbs.

Did I get shorted over 2 lbs. of CO2?

I'm estimating ~54% full/~46% empty, is my line of thinking correct?

 

[Vale71]

Assuming your scales are working properly and 7.62 lbs is indeed the tare weight then yes, you've been sold a little over half of what you were expecting.

 

[mikescooling]

You would need to know the weight of the tank and valve with no CO2 in them, then weigh it after a fill. The tanks get hot when they slam all that gas in, it makes them hard to top off without cooling the tank. You can bring the tank in a ice bath and let them fill it when it's ice cold to get a good fill.

 

[Vale71]

It's a CO2 tank which means it gets filled with liquid CO2 out of a cryostat. The tank actually gets cold and not hot as it's filled.

 

[day_trippr]

It gets even colder when the filling attendant has to relieve the head space pressure numerous times to achieve a full rated fill...

Cheers!

 

[Bobby_M]

They should be filling to a few ounces and doing a quick purge to drop the temp of the tank. 2 pounds is a lazy short fill.

 

[rhys333]

My LHBS does exchanges and I've always wondered if they don't fill them as I only seem to get a few kegs out of each tank. I called the supplier to ask if they can do a fill for me and they informed me that they do exchanges, just like the LHBS. I said I wanted mine filled instead, and just the way he responded left me thinking that its standard practice to short you on a fill. Anyway, they agreed to fill mine, but asked me to call ahead so that an attendant will be available.

And I should clarify, I don't think my LHBS shodting me on CO2. Its their supplier.

 

[Chorgey]

Thanks for all the replies. I texted the LHBS but received no response. It sounds like I need to locate an alternative place to get future CO2 fills.

 

[brew703]

I usually use my home brew store to fill my tanks. In the summer, they put the tank in a bucket of ice, then start to fill. Problem is it takes 2-3 hrs to fill a 10 lb tank.
Since I'm working from home I took my tank to a fire safety place. They have a pump system and took all of 5 min to fill plus $5 cheaper. Drawback is they are only open M-F. Not a problem now but when I return to work I will have to either take the day off or leave early. Both HBS and fire safety place is over an hour drive one way.

 

[BrewMan13]

For some reason, the beverage center I take mine to get filled at never seem to be able to get it close to full. Was at ~50% fill last time. But they charge by the pound, so I'm not getting ripped off per se. Helps to bring it to get filled when it's cold - which I do, but still lackluster fill levels.

 

[Vale71]

I usually use my home brew store to fill my tanks. In the summer, they put the tank in a bucket of ice, then start to fill. Problem is it takes 2-3 hrs to fill a 10 lb tank.

That's amateurish at best. Filling through evaporation and subsequent condensation will take so long that it would be impractical to expect to fill to more than 40-50% of nominal. Professional filling is done with direct liquid transfer with the bottle placed on a scale. The bottle sweats like crazy for hours afterwards but it only takes a few minutes to complete the process and you can't get shorted unless their scale is wildly inaccurate.