Airsoft gases and external gas rigs

Hey everyone, I am going to talk about Airsoft gas and external gas rigs.

Lately I have seen a number of questions related to gas guns here and outside of the internet. So I am going to put this together in hopes that it helps everyone understand gas and external rigs a little bit better, and educate those that don't know squat about gas.

Lets start off with what gases are in use. I am going to start off with the lowest pressure and go up.

HFC134A (R134A), Duster Gas (HFC152A, HFC143A, HFC134A) - These are "low pressure" gases designed to run in plastic slide pistols. 134a: [email protected] 30c/86f=96.99

HFC22, Green Gas, Top gas, Propane - These are the most common gas in airsoft currently. Most notable is the green gas and propane. Propane: [email protected] 30c/86f=141.77

Yellow gas (MAPP, MAP//Pro, Proplylene) - MAPP gas, Discontinued as of April 30, 2008. MAP//Pro and Propylene (which are the same). Proplylene: [email protected] 30c/86f=174.54

Red Gas and Black Gas - These 2 I dont have any data for as I can not find much on them. From what I have found out is that red gas is quite a bit stronger then green gas. Black gas is apparently even stronger then red, supposedly anyway. From what I have gathered with the addition of CO2 and HPA into the sport, these two for the most part have been phased out.

Addition: Well I thought it was phased out... http://www.airsoftsniperforum.com/3...oft-gases-external-gas-rigs-2.html#post140168

Red Gas-

BuMS said:

According to wikipedia, red gas is HCFC-22, and it seems to be illegal in some places(US).

The pressure of red gas(HCFC-22) is about 132 PSI.
Propane, which is the main ingredient in green gas, is about 124 PSI(Green gas is a bit weaker then propane, as it's a mixture).
And propane has been known to be too much for some guns.

You made me look something up, and I learned something new... Shame on you!

Edit: It might be alright, if the weather is very cold.
But the consequence, of leaving it in the gun in room temperature, is a unknowen factor, as it depends on your gun being able to handle the pressure.

Click to expand...

CO2 - This gas is the next most common gas in airsoft. It is a very versatile gas. It powers pistols, grenades, rifles, and more. CO2 has an output pressure between 800-1200psi depending on temperature. 1200 is when the designed safety devices fail and vent the gas in order to insure no catastrophic vessel failures occur. In other words it keeps the canister from exploding.
CO2 comes in a variety of containers, ranging from 8gram cartridges up to 50 lbs cylinders (which weigh approx 200lbs). This gas is also cheap.

Thus far all of the gases I have listed are all liquid gases. I refer to these as "dirty" gases. I will explain why.

Source: Gas duster - Wikipedia, the free encyclopedia
When the top is pressed down to open the valve, gas flows out through the nozzle. The pressure inside the can therefore drops, and is no longer sufficient to keep the contents as a liquid; so some of the liquid boils, until the equilibrium pressure is re-established. The vaporization of a liquid is endothermic; thus, heat is absorbed, the temperature can reach −50 °C (−58°F), and the can becomes cold.
Continued use over a short period of time results in the reduction of the can's temperature. As the temperature drops, the vapor pressure of the liquid also drops, resulting in decreasing force of the gas at the nozzle. When the force of the ejected gas at the nozzle is insufficient to accomplish anything useful in terms of dust removal, and the temperature of the can reaches the boiling point of the liquid (that is −25 °C (−13 °F) for difluoroethane), the liquid no longer evaporates into gas in any useful quantity. The can must then return to room temperature before it will again provide sufficient gas flow. Alternating between two cans (allowing one to warm while the other is being used) is one way to work around this problem during an extensive dusting job. Warming the can with a heat source can be dangerous as the can may overheat and explode.
A related category of product has an internal dip tube that reaches to the bottom of the can, so it sprays the liquid. It evaporates very quickly, chilling items it touches in the manner that dry ice (solid CO2) would. These "chill spray" cans are used to troubleshoot malfunctioning electronic equipment.

This is referred to as Cooldown. All liquid gases do this.

I hate liquid gases, the reason is because of the endothermic reaction. This has destroyed more orings and seals in my paintball equipment then I care to calculate. The same thing happens in airsoft gear as well.

The last gas I have for this list is HPA, or High Pressure Air. As far as consistency goes, all gas guns that are not powered by HPA are unregulated. Which means the pressure of the gas going into the barrel is what ever. Which gives you massive jumps in FPS.

HPA needs regulation. Seeing as it is just compressed air in a bottle at high pressure (3000-5000 psi depending on tank.) All tanks used in airsoft are paintball tanks which have a regulator to bring the output of the tank to 850psi, or 450psi if you get one with a Low Pressure reg on it. HPA is not affected by cool down as it is not a liquid, it is also not affected by ambient temperature.

Most tanks come in 2 pressures 3000 and 4500psi. There are others but those are rare. Tanks also come in a variety of sizes as well as pressure. The size is in Cubic Inches, or CI. Sizes range from 13ci to the massive 144ci. Clearly the larger the ci the bigger the tank is.

Addition: You remember how I said that liquid gases were "dirty" well HPA can be dirty as well. Literally dirty, as in dirt and dust. Some fields have compressors that do not have filters, which allows for dirt and such to enter the tank. Something to keep in mind should your P* act up when you filled your tank from a dusty, dirty field.

A note on HPA tanks. All HPA tanks need to be re-certified every few years. For the aluminum tanks (also known as "steelies" due to their weight) is every 3 years. While the fiber wrapped tanks are every 3-5 years. This is merely a general rule of thumb, you need to check on your tank the exact details for hydrotesting. Addition: Examples of hydrotested tanks.

Also make sure they have the proper markings for your country, US D.O.T stamped, EU PI stamped, everywhere else I think is TC stamped.

EXTREMELY IMPORTANT: DO NOT, UNDER ANY CIRCUMSTANCE, PUT ANY KIND OF LUBE IN YOUR TANK OR THE TANK'S REGULATOR, AS THEY COMBUST UNDER THE PRESSURE OF THE TANK. THIS WILL COMPLETELY RUIN YOUR TANK, REG, AND YOUR DAY. This has happened to me twice now. One of those times was today!

When paired with a good regulator or 2. You can lower the pressure down to 60-135psi, the pressures that are used in most high end paintball guns and p* systems. I will get into this next.

Ok. Now its time to get into Regulators.

How does a regulator work? Here is the answer.

Source: Regulators Explained:

In today's high-tech world of paintball, almost all of us use a pressure regulator of one kind or another. One of the first in the industry was, of course, the AIR valve in the Automag, introduced almost a decade ago. Now, we have multi-stage "pressure balanced" HP nitrogen systems, inline regulators, more paintguns have regs as part of the operating system... the list is endless.

So how do they work?

First off, in the very basic design, the pressure regulator is essentially a spring-loaded check valve. Fig. 1 shows a simple, basic regulator. This design is used, in one shape or another, in the Automag line, Air America's HPA systems such as the Raptor and Apocalypse, and even the ANS 'JackHammer' pneumatics reg for the Autococker, among several other applications.

Fig. 2 shows an RG-1 type reg design. The concepts are essentially the same, but for simplicity's sake, the majority of this article will be in reference to the fig. 1 system.

In this example, lets start with the 'adjuster' backed off, so there is no tension on the 'reg piston'. What is happening here is, the high pressure (supply) air is pushing the 'reg seat' against the 'seal'. This seals the HP air from escaping, and probably getting into trouble somewhere.
This seal is made, because the 'supply' air is at a higher pressure than the 'output' air, which keeps the seal shut. So now, we crank down on the 'adjuster', which begins to put mechanical pressure on the 'reg seat'. However, the 'supply' pressure is still greater than the spring pressure against the 'seat', so it remains closed.
But if we keep cranking down on the spring, eventually the spring tension will overcome the 'supply' pressure, and force the seal open. So now, air is allowed to flow between the 'seat' and the 'seal', and begins to fill up (pressurize) the 'downstream' side of the reg. (Toward the gun, assuming nothing leaks.) At a certain point, because the 'reg piston' is in a sealed area on the 'low' pressure side of the reg, the additional pressure in the downstream side also begins to push on the reg piston, helping the supply air pressure force the reg seat closed.

This is the tricky part. Assume the 'supply' air is X psi. Assume the output (or downstream) side rests at less-then-X psi. Once you start cranking down on the 'adjuster', the spring pressure on the 'reg piston' gradually forces the 'seat' open, allowing the 'supply' pressure to flow to the 'output' side. This begins to pressurize the output side, which in turn begins to push against the 'reg piston' against the force of the spring. At some point, the supply pressure against the 'reg seat' and the pressure against the 'reg piston' from the output side overcome the spring's pressure and force the seat closed again. At this point, everything is in a state of balance.

Now, do something stupid like fire the paintgun or crank down on the adjuster harder, and things happen all over again.

When you fire the paintgun, that reduces the pressure in the 'output' side of the reg, so that the spring tension can again force the 'reg seat' open. This allows a small burst of air back into the output side, and as soon as pressures equalize again, the reg seat closes. (This is known as "recovery" and faster recovery is better, to prevent velocity drop during rapid fire.)

Or, in the other example, you crank down on the adjuster, which adds spring pressure which forces open the 'reg seat' again. And again, the seal allows a small volume of air through, and as soon as pressures equalize again (This time at a higher pressure) the 'reg seat' closes again.

The action of the reg seat opening a fraction of an inch and repressurizing the output side happens each and every time you fire the paintgun or alter the velocity. The reg could also be having to constantly work very slightly if your system leaks, as it tries to maintain downstream pressure.

Now, this is a very simple, basic description of how a regulator works. There are a lot of other factors to consider, such as how the loss of the 'supply' side pressure can increase the output pressure. Once the tank pressure drops, it becomes easier for the spring to push the seat open,and
that's the equivalent to increasing the spring pressure, so the output pressure rises, even though the adjustment is unchanged. Also, as most 'Mag owners will testify, the condition of the reg seal can become critical; if the seal/seat leaks, there is nothing to stop the full tank pressure from passing through to the rest of the gun. A dangerous situation in some cases. (That's why HPA systems have burst discs on the output side.)

There are quite a few different designs of regs in Paintball, though most can be classified as one of two types: The most common type has the adjuster vary the tension on a spring, which acts on a reg piston and seat, against a fixed reg seal. This design is used in UniRegs and Automags, among others.
The other design has the adjuster press directly against the reg piston and movable reg seal, which acts against a "fixed" spring pack. This is the basic design of the RG-1, Angel foregrip reg and WGP reg.

There is, of course, far more to pressure regulator technology than this little article can hope to cover. But the basics are here, and hopefully, this will help you to better understand the inner workings of most regulators.

Ok, now that that you know how they work you should understand why they are a big deal.

I use the term Recharge instead of Recovery. When looking around for a good regulator setup Recharge rate is important. Mostly for those with P* systems and the like. As Doc said, the better the recharge rate the better the reg. This is true, but it is not as vital in a sniper rifle, but if you use your rig for different systems then it will be.

Now as far as setups go, dual regulator setups are generally better for sniper setups then single reg setups. Especially with CO2. Dual regs allow you to "dial in" your fps better then a single. They also do a better job regulating the airflow over a single. On average, of all the signle reg setups I have seen and worked on I see an average FPS difference from shot to shot of about 5-7 fps.

Most dual regs I have seen and worked on have a FPS difference of maybe 1 fps at most, in one case 5 fps due to old grease and gunk buildup.

From my experience, some will argue this but I know this as fact, all regulators have a break-in period. The actual amount of time for this break-in varies from reg to reg and brand to brand. There are far too many factors to account for when dealing with break-in time so I am not going to get into that. DO NOT ASK ME "How long will it take to break-in BLAH reg?" I AM GOING TO IGNORE YOU. Just getting that out of the way.

Now most regs were built for HPA in mind, not CO2. Just be warned that not all regs handle CO2 well. All of Palmer's Pursuit regs will handle CO2 just fine for the most part, may need more maintenance ever so often, but that comes with the territory of using CO2.

Not all regs are maintainable. These are normally the cheap ones. Make sure you buy a reg that is rebuildable. This will keep you from having to replace your reg every time they break. Yes regs do break down from time to time. Most rebuild kits are cheap compared to the price of a new reg.

I will add more to it later, for now I am going to go get more burn cream...
Let me know what else you guys want to know, I will add it to this.