Filling your tanks at home could save you money and time. Kind of like Sam's Club, buying in large bulk can save quite a bit of money. In this article, I will discuss some guidelines to properly fill your tanks with both types of gases. If you have not done so already, please read my CO2 and Nitro - F.A.Q. to get a basic understanding of these gases used in paintball. Remember, CO2 tanks are for CO2 and Nitro tanks are for nitrogen or compressed air. Do not switch and attempt to fill these tanks with the wrong gas. Harm to your equipment and personal injury is possible.

I do suggest that you get your tanks filled by properly trained personel whenever possible. At least consider these trained personel to help you understand these guidelines.

CO2 - What you need

This is the granddaddy of gas used in paintball. When paintball first started, paintball markers used little disposible 12g CO2 cartridges to propel paintballs. Then came the bulk tanks that can hold anywhere between 4 and 20oz. These were called Constant Air (or CA for short) because it seemed like it was constantly had air as compared to the 12g cartridges.

To fill these CA CO2 tanks, you will need a scale to weigh the tanks. This needs to be an accurate scale or else you could under-fill or over-fill your tank. Under-filling a tank and you will not have as many shots as you could. Over-filling and you can rupture the tanks burst disk.

Another item that you will need is a "fill station" that is made for CO2 only. This is a combination of hoses and valves that will help you fill your tank. Make sure it consists of a bleed valve, a fill valve, and a pin depressor. All these items will be attached to some air lines.

The last thing that you will need is the bulk tank. These can be found at welding supply shops or other various air distributors. These bulk containers will be a good size item. Some can be up to 5 feet tall. Find a place for this tank where you will not need to move it. Also, because it is so large and heavy, be a good idea to secure it with straps to keep it from falling over and hurting someone or anything. One last thing, it needs to be a siphon tube. In other words, your filling your 20oz. tanks with liquid CO2 and not just gas. This are often marked as siphon tube or dip tube installed.

A wrench will also come in handy to attach the fill station. Since CO2 is a "cold" gas, you could go through some o-rings. Have several on hand ready to go.

CO2 - Filling

Your fill station should be already attached to your bulk CO2 tank. Make sure it is on tight with the wrench. First, you must drain the tank you wish to fill. You really cannot top off the tank with CO2 without the risk of over-filling it. Screw the tank your wanting to fill into the fill adapter. Bleed the tank until it is empty. This will chill the tank, making filling easier. If you do not chill the, filling an unchilled tank that is already empty will only be filled somewhere between 25% and 35% full.

If the tank you are filling is completely empty, you must fill the tank with some CO2 first, then bleed it out. Not much is needed. Somewhere between 1 and 3 ounces. Depending on the size of the tank. You will need to bleed the entire contents of the tank before you actually fill it.

Attach the tank to be filled onto the fill adapter. Make sure that it is tight. Weigh the tank before you open the valve on the bulk tank. Make sure that your bleed valve is closed. While watching the scale with the tank on it, open the valve to the bulk tank. Fill the tank under it's rating by about 10% to 20%. As the tank warms, the gas will expand to the right levels. So, for a 16 ounce tanks, fill it to 13 or 14 ounces. Filling it to the full 16 could cause the tanks burst disk to rupture.

Turn off the main valve on the bulk tank. Do not take the tank off yet. Remember taking a tank off your marker and all this air comes whooshing out? It will happen here. But to not have it do this and save o-rings, unscrew the fill adapter until you can feel the resistance decrease and stop twisting the tank. Open the bleed valve to relieve the pressure that is still in the air line between the bulk tank and the tank you just filled.

After you bleed off the air in the air lines, finish unscrewing your tank. Best to let the tank warm before using. Doing so will ensure that the tank will not rupture the burst disk.

If your burst disk does rupture, there easily changed. Refer to my anti-siphon article and follow the simple directions. Probably not a bad idea to have a few of these around along with your o-ring.

Nitro - What you need

This is an easy gas to fill without the need to chill your tank first like you need to do with CO2. What you need is a decent fill station that is for compressed air or nitro. Do not use one for CO2 as it is a different setup and different pressure requirements. This is a simple attachment that more or less screws onto the bulk tank and has a female quick disconnect air fitting. The tank your filling will connect to this female fitting. The picture below shows one for a scuba tank. A filler is slightly different for leased nitro tanks.

You will also need a bulk tank. There are a few options to go to fill a tank. The simplest way is to invest in a scuba tank. You can sometimes find them used from scuba shops for a decent price. To get these bulk tanks filled, you can do it at either the scuba shop (if they have the capabilities), your local firehouse may be able to do it, or at bulk gas facility. Expect to pay around $5 to $15. These scuba tanks will need hydrotested just like your smaller nitro tank.

You can also get nitrogen in bulk from a gas facility. This is almost a pure reservoir of nitrogen. Nitrogen can be used for paintball, but is not very common because of the price. If you have the desire to use Nitro, that is fine. I find it more expensive than using scuba tanks unless your a public field. Nitro tanks are leased and are switched out for new, filled tanks. The lease itself I find costs about $10 per week. However, replacements are between $50 and $100.

If you choose to use any of the above tanks, best to secure them against a wall with a strap or chain. Just incase it is knocked over. Place them in an area that doesn't require it to be moved if possible.

The last option is an air compressor. Ones that are rated to fill your tank some 3,000 to 4,5000 psi are very expensive. Your talking four figure dollar sign, then the decimal point. The ones that you find at home builders stores or automotive stores can only fill up to 300 psi. Not quite close enough.

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Nitro - Filling

Now that you got your bulk tank, it is pretty simple. Like I said, there is no need to weigh the tank before and during the filling process. But, there is a gauge on the nitro tank that should be watched. You need to watch that gauge as you fill.

Since the scuba tank is more common for fills, i will describe how to fill from that. Nitro tanks are very similar. Just a slightly different filler.

Secure the fill station to the scuba tank if your using one. Attach the tank you want filled to the female air fitting and open the valve just enough for air to move. Be careful, your tank will warm. Because the air is compressed so much, there is lots of friction going on. To reduce the stresses of filling the tank, fill your tank in increments. Fill it to 500psi, then stop and wait about 15-30 seconds to let it cool some. Re-open the valve and fill another 500psi. Keep doing this until you get to your desired psi. Do not over fill. Doing so can cause the burst disk to blow.

A small hint for those using a 3,000psi scuba and filling a 3,000psi tank. You can simply open the fill station valve and let the air equalize. Both tanks will equal in pressure so long there rated the same. The next fill will be less than 3,000psi. The next fill after that will be more less. Depending on the size tank you are filling and the scuba tank size, the number of fills will vary.

After the tank is filled, shut off the valve from the scuba and open a relief valve. This will enable you to easily take off the air tank.

For you guys rich enough to get nitrogen (by the way, no real advantage between these gases), be very careful, as this will make things very hot.

For you guys with the adjustable tanks, you will find yourself with two gauges. Watch the one closer to your reservoir. This measures your fullness of your tank. The one closer to the pin valve registers the output of your adjustable regulator.

For a compressor fill, it will depend on the type of compressor. Consult your owners manual for discharge. Filling the air tank is the same as above. But you need to watch the gauges carefully so as to not over fill the tank. After the tank is filled, shut off the compressor and open the relief valve. Remove the tank.

Well, that is it. Those are the guidelines to filling air tanks at home. Be careful and be safe.