DumboRAT?s GasPrimer FAQ, May 2002

?I will be editing the broken links from this original document, since alot?of sites referenced are long gone.?Even though this info is a bit dated, it's still a solid reference for the new airsofter.

DumboRAT?s GasPrimer FAQ, May 2002

This was originally submitted to the airsoftguns.com mailinglist in response to a fellow player's question regarding a specific brand of Taiwanese "Green Gas" he saw on-sale. He wanted to purchase it as it he felt that it was a "good deal," and wanted to know if the gas that he indended to purchase was a "good all-around GBB gas."

My hope is that this will clear up some of the common misconceptions and various "urban myths" surrounding both the proprietary airsoft gasses (i.e. "Toy Jack/Top Gas," "KWC PowerBombe," "WA Gun Power," etc.) as well as make clear the role of using substitute, "generic" "computer duster" gasses. I would urge ALL gas-powered replica newbies to read through this post in detail.

I hope this helps!

Allen (cxl77@po.cwru.edu)
aka DumboRAT

PS: For those of you new to airsoft GBB's, please read the GBB section in the second half of my "Newbie FAQ" here:


First, let's go through the basics to be sure that we're all on the same page.
HFC132a, 1,1,1,2 tetrafluoroethane, is also known commonly as "duster gas." Readily available here in the States. Somewhat harder to get in Europe and other overseas countries. Brand-names include Tokyo Marui's "Blue Gas" and Western Arm's "WA GunPower."

Taiwanese "Green Gas," CH2FCF3CH3. Sold only as proprietary airsoft propellant gasses. Brand-names include Toy Jack/Top Gas, HFC, UHC, and Omega. Typically, they are also referred to as "Super Power Green Gas."

HFC22, more correctly referred to as HCFC22 (thanks, Phoenix!), chlorodifuloromethane. Getting true HCFC22 is becoming harder and harder to obtain in the States as this is on the "slow-ban" list due to the fact that it is harmful to the ozone.

Now, to add to the confusion, the following contribution from Rotor ? Thanks!

R12 is also known as CFC12, dichlorodifluoromethane. Being a hydrochlorocarbon with high ozone depleting properties, it is currently banned from manufacture in the US and many industrialized countries world-wide. Currently, it is "reclaimed" and re-used. Production in the US stopped as of Jan 1, 1996.

HCFC22, which is chlorodifluoromethane, is, as I?ve mentioned above, on the "slow-ban" list (it's not "as harmful"), scheduled for complete cessation of production by the year 2020.

I?ve yet to see R12 Freon used in airsoft. Perhaps it was before my time?.. However, I also have yet to see bottled HCFC22 for airsoft ? I simply have not seen this marketed ANYWHERE, aside from true industrial or refrigeration use. The supply that I have is from an old cache of scientific laboratory use coolant which I?ve ?jury-rigged? for use?.. Anyone? There is a website that sells bulk canisters of HCFC22, but without a proper pressure-regulating adaptor, you?ll run the risk of overpressurizing your fill and (1) destroying your GBB and (2) possible personal harm to yourself!

"Red" and "Black" gasses. Unknown chemical consitutency (I've yet to get a canister of this stuff, or see it in person). Rumored to only be suitable for use in highly upgraded GBB's.

The current consensus among the players as well as recommendations from certain airsoft GBB manufacturers that Japanese GBB's, ie. Western Arms, KSC, Maruzen, etc., only be fed HFC134a. As such, many Stateside players have, instead of paying higher prices for the TM and WA airsoft specific HFC134a gasses, gone to jury-rigging fill adaptors in order to use common "duster gas." This is a perfectly acceptable alternative, as the chemical constituency for the gasses are the same. Some players have complained and others warned that common "duster gas" does not contain any lubricant, as with the airsoft-specific propellant gasses. However, this is easily remedied by dropping one or two drops of silicone oil directly onto the incoming gas fill nipple and subsequently introducing fill gas into the magazine. This process causes sufficient atomization of the lubricant oil into the magazine gas resevoir, which is then spread throughout the GBB during discharge. There's nothing wrong with simply spraying or dropping in a bit of silicone oil at the incoming gas fill port at the bottom of your magazine immediately prior to each fill as I've suggested. If anything, when done properly, it will most likely actually introduce much more than the small percentage of lubricant actually present in the proprietary airsoft gasses.

Note that players in who have used difluoroethane, which is also a common compound used as "duster gas," have experienced slightly different performance characteristics than that of true HFC134a (1,1,1,2 tetrafluoroethane). Most Japanese-made GBB's are optimized for use with HFC134a — providing both an outstanding amount of gas-efficiency (around 80 cycles per fill) coupled with good muzzle velocity (usually around 250 fps. with 0.20 gram BB's for the high-end models).

Generally speaking, the various Taiwanese "Green Gasses" that I've come across are all of the chemical formula CH2FCF3CH3. Additionally, all seem to provide the airsoft GBB with considerably more power (in terms of both quantitative observed muzzle velocity as well as subjective feel of "blowback kick/recoil") than HFC134a. Such an external manifestation of power is most likely reflected in the internal operating pressure that the GBB is subject to while using "Green Gasses." Likely as a result of the mechanical shock of increased "recoil" energy, in combination with the likely much higher operating pressures, the stressed parts are thus made more prone to failure. For whatever reason, Japanese GBB's simply do not seem to tolerate such abuse as well as their Taiwanese-made counterparts.

Strangely, many Taiwanese-made GBB's require the use of the "more powerful" Taiwanese "Green Gas" in order to achieve the same muzzle velocity as Japanese GBB's do while using the considerably "less powerful" HFC134a. This is perhaps the single factor that demonstrates the superior performance engineering of the Japanese GBB's. Ironically, most Japanese GBB's are not built for the abuse that constant use of Taiwanese "Green Gas" can inflict on a GBB. The above consensus of using only HFC134a in Japanese-made GBB's spawned from MANY players' misfortune of having suffered various broken parts due to the use of various brands of Taiwanese "Green Gasses" (and other gasses that are "higher-powered" than HFC134a) in their expensive Japanese GBB's.

One common misconception is that "Toy Jack/Top Gas" is "more powerful" than the various Taiwanese "Green Gasses." This is not true — some canisters of "Top Jack/Toy Jack" gasses come into the US with an importer affixed label declaring the true chemical components of its contents. From such labeling, you can easily see that "Toy Jack/Top Gas" is clearly CH2FCF3CH3.

Typically, Taiwanese-made airsoft specific "Green Gasses" incorporate, as a small percentage of their content, a silicone additive for lubrication of the gun's vital cyclic and frictional parts and surfaces — as well as various neoprene/rubber o-rings, seals, and gas route packing. This is easily evidenced by the small amount of oil left over on the gas route packing membrane after repeated discharge of the gun.

True HFC22 is chlorodifluoromethane, a chemical compound that is distinct from that used in various Taiwanese "Green Gasses." Yet, many mis-informed individuals insist that the two are one and the same. This can be easily dis-proved by a simple chrony and a gas efficiency test. Depending on the particular GBB's valving and mechanicals, you will more than likely find a considerable difference in performance in terms of muzzle velocity and gas efficiency when you substitute HFC22 for Taiwanese "Green Gas," and vice-versa; even with identical fill-times and testing conditions. This only stands to reason if the two gasses are indeed NOT the same.

While it is not recommended that you use the various Taiwanese "Green Gasses" or HFC22 in your Japanese-made GBB, many players do choose to run that risk in trade for increased muzzle velocity. Some players have had the bad luck of having their GBB's literally falling apart in their hands or "exploding" upon their first use of such "high-powered" gasses (cited from both the old, now defunct airsoftguns.com d-board as well as the airsoftzone.com Forums). Others, however, have not had that problem, but are undoubtedly exposing their GBB's to a relatively increased rate of wear compared with their HFC134a-usage counterparts. Thus, the decision between this trade-off of performance vs. durability is completely up to you.

A word of caution is that players take statements from the Internet such as "the Tokyo Marui (Japanese) Beretta M9 GBB pistol can take Taiwanese 'Green Gas' with no problems" and see that as a license to run the "higher-powered" gasses in their own M9. The same can be said of recommendations passed for the Western Arms High-Capacity series (ie. CQB/TAC/SpeedComp) and Strayer Voigt Infinity series GBB pistols. While it is true that they *can* "take" such "higher powered" gasses, it does not mean that they are immune to the deleterious effects of such.

The same, actually, can be said of any and all GBB's, regardless of manufacture. The use of "higher powered" gasses, such as Taiwanese "Green Gas," HFC22, "Red," or even "Black" gas may be "possible" in your GBB — but you can bet your ass that your GBB will likely get fucked up sooner than your friends' that's been fed an exclusive diet of "low-powered" HFC134a.


(1a) Some stock Taiwanese GBB's may require the use of the "higher powered" gasses to function properly.

(1b) Furthermore, upgraded GBB's, particularly those with metal slides, may also need to use those gasses for optimal cycling — just keep in mind that even though a metal slide will likely mean that you won't suffer from a cracked/broken slide due to the increased operating pressure/intensity, there are always other parts that are also subject to the abuse.

(2) KWC's "PowerBombe" gas is something of a puzzle to me. While the canister clearly declares that it is "HFC134a," I suspect it to be of the same chemical constituency as the other Taiwanese "Green Gasses." Why? [a] My KWC M92FS "Super," when new, refused to cycle properly with use of true HFC134a — only with "higher-powered" Taiwanese "Green Gasses" and true HFC22 did it cycle correctly (this has since become a non-issue, perhaps due to the mainspring losing some of its tension over time?). [b] The KWC gas has the distinctive odor of the Taiwanese "Green Gasses" — while not a very scientific observation, it does leads one to wonder….. [c] Quite a few friends have pointed out that their GBB's seem to pack an extra punch when using this particular gas — which has led them to also believe, independently, that the KWC claim of this gas being true HFC134a may be false.

Again I'm unsure *why* the canister is labeled "HFC134a." However, this is clearly a "factory/manufacturer" label, instead of a true "for-import" purpose "truth-in-labeling" label as affixed to canisters of airsoft-specific gasses that have been imported into the country and obtained through, say, a Stateside retailer.

(3) Outgoing gas "valve." The nozzle on the top of the magazine — termed by WA engineers as the "gas route packing." Like all neoprene/rubber seals, this should get a little bit of lubrication. The atomized lubricant from the intake nipple fill process should be sufficient. However, a little extra on top wouldn't hurt anything. The only thing that I feel I should caution you about is getting lubricant oil/grease into the BB feed tube or the feed lip, which can, at times, cause mis-feeds. As these two parts are closely situated to each other, use care.

(4) Over-oiling will cause you to attract dirt and lint particles. Try to lubricate liberally, yet not overly so. I am sorry that I cannot describe this better to you, but then again, each of us probably has a different definition of "sufficient" lube.

(5) Difluoroethane. Depending on the precise GBB you have (its internal valving differences), you will experience either higher or lower observed muzzle velocity with difluoroethane as compared to 1,1,1,2 tetrafluoroethane. There may also be a slight difference in observed gas efficiency, again based on the exact GBB you have.

An oxidative by-product of difluoroethane, as I found out from another player and confirmed with a bit of digging, is formaldehyde. While formaldehyde is a Class I suspect carcinogen, it is probably formed in such small quantities that the use of it in our GBB's really would not constitute a serious concern. However, I would still recommend against specifically going to "sniff" the gas. Even so, formaldehyde gas, *I believe* (someone please correct me if I'm wrong, here) spontaneously decomposes to formic acid — which may be somewhat harmful, in the long run, to the neoprene/rubber o-rings and seals. Again, though, it is probably formed in such small amounts as to make this a non-issue. It's more likely that your various seals will simply expire due to repeated use.

(6) As a side note, I should point out that HFC22 is more acidic than HFC134a — and that this should also be a concern for those of you who would like for your GBB's to last a *long* time.

(7) From a fellow player, Mr. White: ?Here is my question – what happens if i load the clip 1/3 Power Bombe and 2/3 Green Gas? Or lets say 2/3 HFC134a and 1/2 HCFC22? I have not seen anything about mixing gases here (i'm not talking about mixing PC Duster with anything, because obviously that will do no harm). I mean what reaction takes place (i'm not looking for a reply like 'you get a bit of a power incease)??

As for the intermix of gasses, as you know, that's been proposed by many players as an "intermediate" between the more powerful "Green Gas" and HFC134a. However, as to the true chemical/atomic/molecular intermix, again, it's a crap shoot. No-one really knows what happens — empirical data gathered by other players seem to suggest that some sort of intermix occurs, but I have not tried this approach personally, so I can't tell you for sure….

I don't think that the gasses will "mix" as in create a new compound — they're likely inert as they are. As such, the increase in observed power is likely either due to the higher pressured gas either being "shared" in the reservoir equally, or, perhaps, being "sucked up" in unequal "gulps" — thereby increasing power on certain shots randomly, while not on others….

I wish there could be a better explanation, but my guess is that unless someone were to somehow tag and then visualize the individual molecules, no one will know for sure. Meanwhile, I'm sure that those who have been using the "partial fill" technique to compensate for power/cost will continue to do so based on their field-tested observations/trials!

More of my thoughts on this subject: http://www.airsoftzone.com/forums/message.cfm?topic_id=5623&forum_id=11

(8) Typically, you can find spray silicone lubricant at the local hardware store. However, most include some kind of additives as propellant and also as an evaporative aid. As my own knowledge of chemistry does not extend that deeply, I tend to keep things simple, and choose to use 100% silicone oils/gels from hobby shops.

You can typically obtain 100% silicone oils in the form of "Team Associated Shock Oil" from many hobby shops (or on-line from www.towerhobbies.com, just use their search function to locate the product). Anything from 10 to 30 weight will do.


aka DumboRAT