Carbon dioxide (chemical formula: CO2) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state.
For more scientific and technical information on carbon dioxide, read here.
In a bottle, CO2 is in liquid form. It expands into a gas upon release. While in the bottle, it holds the vapor pressure of the CO2, which reflects the pressure output of the bottle. Generally, this pressure is 800+ psi, depending on the temperature of the bottle. The CO2 Dynamics Chartrepresents the pressure of a CO2 bottle with a given pressure.
Safety is the number one factor when using CO2 for any launcher application. Generally, pvc is used in launcher construction. While pvc is a great material to use, care must be taken when using CO2, as pvc is not able to withstand the pressures generated. Also, pvc becomes brittle when subjected to the cold of the CO2.
This, however, should not discourage the use of CO2. There are several safety precautions one can take to avoid damage or serious injury:
- Use a regulator; a regulator allows only a certain amount of pressure into the chamber at a time. Palmer's Pursuit Shop produces one of the finest CO2 regulators on the market, and can easily be hooked up to most launchers as they have many different configurations.
- Use a safety relief valve; these valves will open when a chamber reaches a certain pressure, allowing excess pressure to bleed off. These should be used with a regulator, in case the regulator fails.
- Use parts rated for the pressure; launcher parts, such as metal pipe, can be used in place of the pvc if desired.
- Don't use CO2; if one does not have the confidence to use high pressures, they should not be used.
CO2 For Launcher Applications
CO2 is commonly seen being used by paintball markers. It can also be applied, in the same manner, to be used in a pneumatic launcher. There are three main methods for using CO2 in a launcher, each of which is discussed below.
A 12g CO2 cartridge, or CO2 powerlet, is a small CO2 canister that holds approximately 12 grams of liquid CO2. These cartridges are non-refillable and are generally used as ammunition once empty. It is connected to a launcher via a quick change adapter.
Generally, one cartridge is used to fill a chamber. A simple formula is used to give one a general idea of how much pressure a cartridge will put inside a given chamber size. The formula is as follows: 4200 / chamber volume (cu in) = chamber pressure (psi)
For more detailed information on pressures related to 12g cartridges, read here.
Portable CO2 Tank
These tanks come in different sizes and are most commonly seen being used on paintball markers. A regulator is used with these tanks to set the chamber pressure to a certain psi.
Bulk CO2 Tank
These are larger tanks, generally used to fill a portable CO2 tank. They can be used with a launcher, and the same techniques used for a portable CO2 tank is the same used for a bulk tank.
Hooking It All Up
Here is a thread at Spudfiles that contains detailed information on how to connect these systems to a launcher.
Frequently Asked Questions
Sometimes in the forums, a question will arise about CO2. Generally, these are the same questions. Two threads in Spudfiles have been started to attempt to answer these questions and are linked as follows:
CO2 FAQ by Trae08 This FAQ covers a lot of the very basic questions and is a good place to start when one has a question.
CO2 FAQs by hubb017 This thread picks up where Trae08 left off. It covers more specific questions, including the formula to figure out how many shots one can expect from a portable / bulk tank.
CO2 is a fine gas to use in a launcher application. It is readily available and is fairly cheap. As always, be safe and have fun.