Paintball

[hmudd13]

I have around 12 aluminum 20oz tanks and they all fill to 3 lbs, except the siphons and anti siphons that weigh a couple of oz's more. I have 1 steel tank that weighs in at 3.4 lbs full.

The next time you need your tank filled, empty it and weigh it with a kitchen scale.
Then weigh it when you get back. You'll know if you're getting ripped off or not.

[HP_Lovecraft]

Originally Posted by drg

Actually 3 lbs is a well-known figure, for, as I mentioned above, a Catalina tank and basic pin valve.

Having filled tanks for about 10 years, I've never known the figure. Never wanted to know, since if you followed safety protocol, it would be of no use.

I don't see how this would be a speed advantage, since in order to use this method correctly, you would have to have a chart with the following weight correction for:

Tank manafacturer- ie Catalina, Scott, etc
Tank material- Aluminium, steel, fiber, moly, etc
Tank rating- 1800psi, 3000psi, etc
Pin valve type- pin-valve (tippy, Shreader), Thermo, CamAir, etc
Pin valve accessory- On/off, Quick-fill, guage, etc
Pin valve size- ie 3/4", 5/8"
Pin valve material- Brass, etc
Finish correction- Plating, anno, brushing, camo, wraps, tape, etc

OK, so imagine you have 8 seperate charts with weight corrections.
SOmeone hands you a 20oz, and you take a few minutes to figure out all the variables mentioned above. Then another 5-10 minutes to look up each variable into the weight correction charts. Then add all the corrections together to find the offset, on a calculator......

THEN with that number, fill the tank. Sounds like a lot of work to be safe, when you could just zero the tank, and fill it normal. No need to underfill, and rip off customers either.

I think LK13 is right- SOunds like a scam to either sell burst discs, or save CO2 by grossly underfilling tanks.

[Grivooga]

Back when I was using CO2 I just weighed my own tank when empty and wrote the empty weight and full weight on it with a paint pen. Not really proper safety procedure if someone trusts the figure blindly but can save a bit of time for someone who knows the figure is accurate. Of course this was back when people actually took the time to properly fill a tank. Which rarely seems to happens any more. Seems that most people just fill it til it stops flowing now. Of course it's a moot point for me since the only CO2 I use is 12 grams in my Tac8 or PGP.

[himurax13]

Hmm, nearly every 20 ounce tank I have ever filled weighed about 28 ounces after bleeding them. 48 ounces is 3 pounds after all. I only fill to about 18 ounces when it is hot out cause the burst discs tend to blow when exposed to sunlight in the socal heat. My field only does all $10 all day air fills so we never charge by the ounce or per 1000 PSI.

[drg]

Originally Posted by HP_Lovecraft

Having filled tanks for about 10 years, I've never known the figure. Never wanted to know, since if you followed safety protocol, it would be of no use.

I don't see how this would be a speed advantage, since in order to use this method correctly, you would have to have a chart with the following weight correction for:

Tank manafacturer- ie Catalina, Scott, etc
Tank material- Aluminium, steel, fiber, moly, etc
Tank rating- 1800psi, 3000psi, etc
Pin valve type- pin-valve (tippy, Shreader), Thermo, CamAir, etc
Pin valve accessory- On/off, Quick-fill, guage, etc
Pin valve size- ie 3/4", 5/8"
Pin valve material- Brass, etc
Finish correction- Plating, anno, brushing, camo, wraps, tape, etc

OK, so imagine you have 8 seperate charts with weight corrections.
SOmeone hands you a 20oz, and you take a few minutes to figure out all the variables mentioned above. Then another 5-10 minutes to look up each variable into the weight correction charts. Then add all the corrections together to find the offset, on a calculator......

THEN with that number, fill the tank. Sounds like a lot of work to be safe, when you could just zero the tank, and fill it normal. No need to underfill, and rip off customers either.

I think LK13 is right- SOunds like a scam to either sell burst discs, or save CO2 by grossly underfilling tanks.

So was it faster to type all that or just say, 3lbs?

It was a well known figure from the days when Catalina tanks were pretty much the only thing out there, so it may predate your experience. One thing is for sure though ... if he took peoples' advice and assumed 2.4 or 2.5 lbs is okay, THAT would be a gross underfill.

And when some noob hands you a 20oz tank with 14 oz still in it, zeroing it might not be the fastest or best course of action.

[AmericanPaintball]

I guess it again that I cringe reading this. I do not know what the actual tare weight of the tank would be, nor the total with the fill, but at PTI we were taught to zero out a scale and then add the amount that the tank would have for capacity. I know this can very as if you empty a 20 oz tank that has 12 ounces in it, you are going to have dry ice in the bottom of the tank, so in the event the tank would frost over we would account for a couple ounces of dry ice still in the tank.

We though were also told to not charge for a weight as then you would have to have calibrated scales, etc. to just charge for the labor of the fill, which then you could avoid paying the tax on the co2.

Anyways, strange to hear the different techniques people have for filling tanks.

[Horizon]

Yes, tanks should be emptied and weighed and then 20 oz. of CO2 introduced into the tank. Having said that, I've filled many 20 oz. tanks from various manufacturers and I have yet to find one that would be completely full at 2.5 pounds. It was probably underfilled by several ounces (probably about 8).