Jump to content

Airsoft Gases actual composition


Dimitri MdP

Recommended Posts

I've seen way too many people confused by what the *fruitcage* their airsoft gasses really are, so guess I'll make a little abstract about it:


All airsoft gases available to use in "green gas" mags are actually liquefied gases. That's why you charge them with the can heads down, so liquid will get inside the magazine, which will evaporate as needed from shot to shot.

The Chinese standard(ish) is measured in Kgf/cm2 of pressure (which they simplify as Kg for whatever reason) as measured at 33ºC (91ºF) of temperature, and goes somewhat like this: 
(pressure / temperature charts in every gas name link ;) )

- 8Kg (113 PSI) "Blue gas": Tetraflouretane (CH2FCF3), aka R-134A, HFC-134A.
Recommended for: Marui and other plastic slide pistols, non-blowback pistols and revolvers; Regular airsoft pistols above 28ºC (82ºF) temperatures, and theoretically up to 50ºC or so, if someone is crazy enough to play with such nut-melting temperature

411z2-LIduL._SY355_.jpg

- 11Kg (156 PSI) "Green gas": Propane (C3H8) + silicone oil. All green gas have the same composition, even those whom state being composed by CH2 FCF3 CH3 (or even more ridiculously, CHZ FCF3 CH3), which are both non-existant and impossible chemical formulas.
All green gas is simply Propane + silicone, higher quality ones like Puff Dino or Airsoft Surgeon simply tends to be dryer (lower silicone content so less crappiness in your hop up) and purer.
If you plan on using propane, bear in mind it must be the pure stuff (Coleman green bottles, Worthington / Bernzomatic blue bottles). Avoid those mixed with Butane.
Recommended for: Regular airsoft gas blowback guns, in ranges about 15ºC to 35ºC (59ºF to 95ªF)

puff-dino-green-gas-600ml.jpgea22a120-0eaf-42cc-ad68-46e69b8ff77c_1.b
 

---------- Bear in mind most "green gas" mags are actually rated for 12Kgf/cm2, so any gas bellow here should be used at increasingly lower temperatures to reduce the actual pressure and avoid damage)----------------------

13Kg (185 PSI) "Red gas": Propylene (C3H6) + silicone oil. Very same thing as Map Pro cans, which are usually far cheaper, readily available, and can be used with the very same adaptor as propane cans.
Recommended for: Airsoft bolt action sniper rifles, gas blowback pistols in temperatures 7ºC to 28ºC (45ºF to 82ºF)

we2g0004x2-sm.jpgf92bf054-9bb3-4658-923e-962dbe92869d_400

15Kg (213 PSI) "Black gas": I'm not sure about the actual contents, any clue would be greatly appreciated.
Recommended for: Airsoft bolt action sniper rifles, gas blowback pistols in temperatures 3ºC to 15ºC (37ºF to 59ºF). 
611FEASAjzL._SY355_.jpg

 

 

- 20kg (284PSI) "Yellow gas". Again, no idea of the actual contents, and actually never heard of it before the news of G&G's owner arrest...
 For the given pressure might be R410A, a common modern refrigerant, near-azeotropic mixture (constant-boiling, which means both it's components have the same pressure) of difluoromethane (CH2F2, called R-32) and pentafluoroethane (CHF2CF3, called R-125). The fact that is constant-boiling is extremely important, as otherwise one of the gasses would boil first (sorta like when you destile alcoholic beverages, you're boiling the alcohol before the water). That would be similar as trying to fill a mag half and half with green gas + red gas: you'd get the lower boiling (lower pressure) gas first, shoot until that gas is over, and then the higher pressure one will start to boil and kick in. So DO NOT MIX AIRSOFT GASES!!

Might not actually be R410A though, as I've read of quite a few people trying to use R410A in green gas mags that failed to actually fill the mags as weirdly enough it has different pressures when in liquid and gas form, so there's that. For that reason i believe it might just be R32, the new kid in the block of refrigerant gases that doesn't have such liquid/gas issue. It's far more environment friendly (lower GWP) than R410A and most other refrigerants, but also is extremely flammable (that's why it used to be mixed with R-125 as an extinguisher in the R410A mix). And the product of it's combustion is claimed to cause hydrugen flouride, which is extremely toxic and potentially lethal. This last claim is highly disputed, with other refrigerants producing far greater quantities of HF when burned, but it certainly shouldn't be purposely set on fire as Propane and Propilene could. "Funny" enough 134A produces far more HF when combusted, but never seen someone warn about it. 
Recommended for: Actually I won't recommend this thing for the above issues. If you're daring enough to try it, please use it in ventilated, open areas and keep it away from flames just in case I'm right about it's composition. I'm not responsible for your own stupidity. Theoretical range should be -3ºC to 14ºC.

-------------------

 

All of the above are gasses you can use in your "green gas mags", but remember they are rated for 12Kgf/cm (170 PSI) of pressure. The temperatures I stated in the recommendations are those that will provide between 90 and 165PSI of pressure, which I've found from experience it's the ideal range for normal operation on most guns.

Using them in colder environments than recommended will certainly increase the gas volume required for each cycle, causing far greater consumption and less shots per gas fill. If you don't have access to the higher pressure stuff, you can get away with it but sacrificing a big deal of milleage. Still the lowest I would go is 65PSI, which means 19ºC for blue,  5ºC for propane, -2ºC for propilene, about -6ºC for black, and -10ºC for that elusive yellow gas,

Using them above the recommended pressure will potentially cause damage to the magazines, which can cause leaks and even make the mags explode or bloat the magazine walls. Some magazines are more resistant to it (like GKH's), but generally speaking I still wouldn't risk more than just a couple extra degrees than recommended. 


Remember this can vary from gun to gun, as gas gets colder as it expands.. That's why using full auto will normally give less shots per charge, as the gas inside the mag has less time to heat back to ambient pressure. Furthermore some guns have better sealing than others, so they consume less gas by avoiding wasting gas on leaks between the magazine gasket and the nozzle, as between the nozzle and bolt carrier / blowback unit.

This is closely related too with the recoil of the gun. Higher recoiling and longer bolt travel guns normally have greater consumption (and therefore more cool down), so don't expect going far lower than the recommended pressures for instance on WE systems (which prioritise recoil). I've went as low as -2ºC with Map Pro (which means 65PSI) on a WE AK and got almost a full load of bbs from a gas charge still, but that's my personal gun and is fine tuned for good sealing . KWA guns on the other hand normally provide weak, sometimes even pitiful recoil (I'm talking to you, KWA AK), but they consume far less gas and therefore are able to mag dump and work on even colder environments for a given gas. 
 

---------------------------

 

Last but not least, I want to clarify a the recurrent myth that higher pressure = higher FPS. Most people think that's true and even switch to higher powered gases looking to increase the power of their guns, only to get a big letdown every time. Or think their power output will vary greatly with just some degrees of ambient temperature, which couldn't be further from the truth. 

I understand the thought is quite intuitive, but they fail to realise the very basics of how GBBRs work: All modern GBBRs use a floating valve inside the nozzle, which compensate the loss in pressure by allowing more volume (and vice versa) towards the front. So the FPS can remain constant despite having several dozens of PSI variance between shots and / or several degrees of ambient pressure, as long as you maintain them in the recommended ranges.

Long story short: don't worry, if you chrono on the cold morning with field legal values (with a couple of FPS to spare, preferably), your gun will stay about the same FPS for all day. No gas gun becomes a hand cannon just by some extra degrees of temperature as many people think. Furthermore, (depending on where you live), you shouldn't even have to change or adjust valves between seasons, only switch to the appropriate gas for the given temperature and you'll be fine.

So the myth is certainly false for 99% of the gas guns out there, with the exception being bolt action gas sniper rifles, as they lack such device. So they certainly increase the power when using higher pressure gases and are extremely affected by ambient temperature. 

-----------------------------
-----------------------------


The other common gas used in airsoft is CO2. It has far higher pressure than green gas mags are designed for, so they use special magazines with stronger build materials and different output valves. Most commonly fed from 12g disposable canisters, but sometimes you can find a few that will get input valves as green gas mags would, and fed from paintball CO2 bottles via a charger, similar (but luckily not identical) to propane adaptors. One of them is the popular "Devil Hunter mod" that allows you to charge GHK "12g CO2" mags from the far cheaper paintball CO2 refillable tanks.
mpFrRu5XlKjxicDnw54CLhw.jpgef7576ad-2c58-4be7-a249-a6150cf6d66d_1.6

YOU CAN'T USE CO2 IN "GREEN GAS" MAGS. It has at least 5 times higher pressure than what those mags are designed for. It should be pretty obvious, but if I've seen far too many magazines destroyed from people trying stupid things.

-------

Finally, another option that is gaining popularity every day is regulated CO2 / HPA rigs. These are tank-and-hose setups that can be tapped to your green gas magazines (with a regulator in between to take the pressure down to green gas working pressures), providing your GBBR or BASR with perfect consistency every time and almost zero cooldown effect. 

Also there are guns that use gas engines fed from the same regulated setup hooked up to the gun internals, leaving the possibility to use the far higher capacity AEG type mags. Some of them have recoil, like Escort/Daytona's and Tippmann's, while others lack such feature and are designed with performance in mind, like Mancraft's, Polarstars's, Wolverine's, etc, I'll just keep it as a sidenote as they are not the purpose of this thread.

---------

Anyway, guess that's it. Any input / comments / question is greatly appreciated :)

Link to post
Share on other sites

Based on my chrono tests, I would be carefull about the fps "low influence". At least in case of MAPP gas the variation is quite high in my opinion. And my guess is the similar results would be with any Green Gas.

 

When I measure my rifle at in-house temperature (20 Cels, ground level, morning) I get about 110-115m/s w/ 0.50 bbs.

 

But when I measur it in the afternoon (25 Cels, 1m heigth) with warmed-up magazines I get 125-130m/s w/ 0.50.

 

And that I would call a considerable difference.

 

 

 

 

Sent from my iPhone using Tapatalk

 

 

Sent from my iPhone using Tapatalk

Link to post
Share on other sites

Regarding temperature and FPS, why would cool down then lower FPS if temperature isn't a factor? 

Temperature is a factor as it lowers the pressure and screws the efficiency, but the floating valve is there to compensate for that and keep the FPS somewhat constant. Any decent GBBR deals with it quite good, and a fine tuned one can have almost AEG-like consistency. 

 

The point was that as long as you use the proper gas for the given temperature and your gun is working correctly (pretty much means a good floating valve -NOT A NPAS- and good seal in the nozzle to bolt oring), you won't see a dramatic difference from the morning to the noon, nor see a constant drop in FPS from shot to shot as pressure would dictate if the floating valve was not there.

 

And similarly, switching to a higher pressure gas won't increase significantly your FPS. 

 

Most of what people blame on "cooldown" is actually just the crappy silicone oil in green gas screwing with your hop bucking.

 

 

Just check these videos by nugentgl... 

 

And by Diles46

 

They are testing very different pressure gases, yet the FPS stays about the same. 

Link to post
Share on other sites

But the temperature effects pressure and volume, as well as the the consistency of the gas (liquid vs. gaseous), and I think anyone who's used a GBB has visibly seen or chronoed their FPS dropping as the magazine gets colder. If the floating valve maintains a constant pressure and/or volume output, then FPS should be the same till the last shot, until it fails to fire due to lack of gas?? On a hot summers day, you won't notice cool down in terms of FPS drop or cycling until you're out of gas, vs. on a cold day where you will see/chrono your FPS drop as the mag cools down/you run out of gas.

 

Am I missing something here?

Link to post
Share on other sites

The floating valve determines when the gas switches from being used to propel the BB out of the barrel vs. it closing and redirecting gas backwards for blow back. The valve reset knocker then determines when the valve of the magazine closes, and this is controlled by the pistol BBU usually that resets it as the slide travels rearwards.

 

Basically how much pressure/gas flow is required on the floating valve before it is enough to push it forward, against the floating valve spring pressure, and closing it.

 

CO2 mags vs. gas is hard to compare because they have very different valve designs. Much stiffer springs and smaller output ports in the valve on CO2 magazines.

 

But, in theory, the flow of gas/pressure to close the floating valve should always be about the same, but you get a more powerful / forceful flow of gas the higher your pressure of the gas is.

 

It's 1:30am here and I've been working like 18 hours so a little tired but that's what I figure.

 

But yeh, real world experience tells you that with temperature drop and cool down in the magazine the performance drops. And saying that is all due to silicon oil in the gas used is a bit odd :o

 

I like to compare it like this.

 

You have 10 liters of water.

 

You pass 10 liters of water through a garden hose, takes a certain amount of time and at a certain rate.

 

Then you dump a 10 liter bucket of water out, much faster and higher flow rate.

 

Kinda the same with releasing gas? :o

Link to post
Share on other sites

The floating valve determines when the gas switches from being used to propel the BB out of the barrel vs. it closing and redirecting gas backwards for blow back. The valve reset knocker then determines when the valve of the magazine closes, and this is controlled by the pistol BBU usually that resets it as the slide travels rearwards.

The floating valve do close the flow towards the front as the pressure builds up in the bolt / BBU, and that's the whole purpose of it. But it's not a "switch" towards the rear.

Both actions happen simultaneously, only the flow towards the front is cut much sooner as it's controlled by the floating valve, while the overall flow (and therefore, the flow to the rear) is controlled by the cycle of the bolt / BBU. 

 

 

But, in theory, the flow of gas/pressure to close the floating valve should always be about the same, but you get a more powerful / forceful flow of gas the higher your pressure of the gas is.

 

But yeh, real world experience tells you that with temperature drop and cool down in the magazine the performance drops. And saying that is all due to silicon oil in the gas used is a bit odd :o

 

 

If your gun has good seal and a decent floating valve, and you're using any gas in the recommended ranges, the drop is far less.

 

"Cooldown" is not a "lower temperature = lower pressure" thing, except for gas BASR, most revolvers, and a few other gas guns that lack a floating valve. But as far a your GBB is working properly and have such device, the FPS will remain about the same despite the pressure. Just check above video by Diles46, their surprise when red gas chronoed the same or even a little less than green is priceless-

 

 

Cooldown really is: 

- First shots with not enough "free" space in the mag for gas to expand properly, which results in some liquid getting out and a few first hot shots, latter stabilising. Typical of guns with short input valves.

- Accumulation of silicone in the hop rubber (check Nugent's video above, the much greater inconsistency of green gas compared to propane)

- Excessive gas consumption due to poor seal between the magazine gas route and nozzle input (like those crappy gen1 SMG-8) or between the nozzle and bolt carrier /blowback unit. Which yeah, cools the gas far more than it should, getting the pressure bellow normal operating limits and therefore the FPS and recoil greatly drops.

- The hop bucking hardening from the resulting cold, cold gas (even liquid spew). 

- The nozzle disconnecting from the hop bucking far before it should (even before the floating valve closes) so the gas doesn't even have enough nozzle connection time to get enough volume towards the bb. 

 

The latter is ridiculously common in pistols and quite common in GBBRs. Which usually gets even worse as your bucking hardens from the resulting excessive cold, and everything just snowballs from there. 

 

 

But seriously, IF your gun has good seal between the magazine to nozzle and nozzle to bolt carrier seals, and you're using the adequate gas, you shouldn't get any noticeable "cooldown" in FPS, only in recoil.

It's just that 90% of the guns out there don't meet such standards.

 

The normal procedure would be: 

- Check nozzle alignment the hop chamber and magazine gas route by taking it out of the bolt carrier. 

- Check your floating valve for proper seal by blowing on it while keeping it mechanically closed. 

- Check your nozzle to bolt carrier / BBU seal by pulling the nozzle to the open position with the bolt carrier / slide out of the gun and pushing it back in while covering the holes. Should feel quite some compression action going on there. This is where most guns fail. Also the spring should be able to return it freely to prevent missfeeds.

- Check the nozzle to hop bucking seal by manually cycling the bolt, the nozzle should stay in the forward position until it reaches the completely open position, disconnects and quickly goes back.

 

This is also why I always recommend Maple Leaf's Autobot buckings, which really grabs onto the nozzle preventing premature separation, which increases efficiency and consistency. On most guns, it's a "night and day" kind of difference. Besides being the best bucking ever for accuracy and range :P

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and the use of session cookies.