The G-Works Gas Saver Plus is a handy little device for utilising cheap cartridges of butane, or gathering together the contents of almost empty canisters into one. Though simple to use, extreme care must be taken. This is a hazardous procedure.
Manufactured by Pickway, the G-Works Gas Saver Plus is the latest version of a handy little device that has been around for a few years now. Changes along the way were the addition of the ‘G-Vent’ to the ‘Plus’ version for exhausting gas from the recipient canister, and in 2020 the addition of a brass liner to the two lindal valve screw threads. It is extremely well machined. Look around and you will find contraptions that do the same job for a quarter of the cost. There are also some clones that look almost exactly the same as the G-Works product and cost half the price. They might be perfectly adequate but not only do I have no experience of them, I’m not interested in them either. I expect a great deal of faultless use over many years. If I am messing around with moving highly volatile gas, in liquid form, under pressure, from one canister to another, I want a well made tool and this is it. Being so well constructed there is less chance of damaging the threads and valves on the donor and recipient canisters. This is not a cheap product but pays for itself in time. There is a G-Works Gas Saver R1 that does not have the G-Vent and is a little cheaper.
The Gas Saver Plus is made in Korea, it is mostly metal, primarily duralumin and brass, with some stainless steel. Duralumin is a portmanteau of durable and aluminium. In addition to aluminium, this alloy is comprised of copper, manganese and magnesium. The Gas Saver Plus measures 46mm wide (98mm with unfolded wire valve control), 16mm deep, 29.5mm high. It weighs 38.5g and comes with a one-year warranty. A simple set of instruction are supplied with the Gas Saver but these are in Korean. The content is included and expanded on below.
If the canister from which gas is being extracted/drained does not have an EN 417 Lindal type valve, a well-made and reliable adapter will need to be attached to the G-Works Gas Saver first. Three Points of the Compass looked at three connector adapters here. Besides those three, there are also some ridiculously little adapters that can be used with the bayonet type cartridges that could also, potentially, be carried on trail. They are looked at in a separate blog.
The instructions in Korean on the side of the G-Works Gas Saver warn the user to beware of overfilling the recipient canister and to check this by weighing it. Weigh in grams, not ounces. Grams are far more accurate and informative when dealing with these small and important weights. Roughly speaking, it should be possible to refill an empty small canister with up to 80% capacity. That is- up to 80-90g of fuel (net 100-110g shown on side of canister), an empty medium sized canister with 185g (net 220-230g on side of canister) and an empty large canister with 360g (net 450g on side of can)
To begin the transfer process it is wise to first head outdoors, or at least away from confined spaces and well away from naked flames. There will be vented gas and you don’t want any flare-ups or worse. Ensure the wire control valve on the G-Works Gas Saver is completely turned off (clockwise). The donor canister goes on top, the recipient canister to be filled below. The correct orientation (which way up) of the G-Works connector is indicated by the printed text on the side of the grey block, which should be readable in the correct orientation, also indicated by the three circles on the side. The large concentric circles go at the bottom. Connect the G-Works Gas Saver to the bottom canister by screwing on firmly but not overtightening. Then screw on the donor can on top, again, firmly, being careful not to over tighten. If you know or suspect there is more gas in the donor (uppermost) canister than the recipient (lower) canister should accept (roughly 80% fill capacity), then occasional disconnecting of the two canisters and weighing the recipient on a set of digital scales is vital to safety.
You can hear the transfer of gas/liquid taking place but even if the sound stops, if the G-Works valve is open and there is still gas in the uppermost canister, there is still some transfer of fuel taking place. It is very easy to overfill the recipient canister. Do not hesitate to pause operations during the process, disconnect and weigh the lower canister. A good pair of digital scales is a very necessary extra component in this process. Keeping a written record of weights as you progress is a helpful approach. Take your time and do it in small steps. An overfilled canister is dangerous and could potentially explode in use or when warmed. At the very least, an overfilled canister could pop the dished bottom. Before disconnecting either canister ensure the wire control on the G-Works Gas Saver is closed. My G-Works Gas Saver weighs 38.5g so I can leave that connected to the recipient canister when weighing and simply deduct that from the gross weight to obtain a tare weight. Deducting the (known) empty canister weight gives me my gas content weight.
The canister to be filled must have sufficient space to accept the amount planned to transfer to it. Ideally, prior to the transfer, place the bottom (accepting) canister in the freezer for 10-15 minutes. This will help create a pressure differential. If this is not possible or impractical for some reason, keep the canisters in the vertical position and turn off the valve with the wire control during the transfer process, and press the brass release valve button for 6-7 seconds. This will relieve pressure in the receiving canister and the transfer of gas can be resumed. Also, if gas (liquid) transfer halts, try closing the Gas Saver valve and venting from the lower recipient, that should enable transfer to resume.
This product collects the remaining gas from the upper canister using the pressure difference. While it is preferable to use a freezer to chill the recipient canister, it is not an essential step.
Refilling from one of the thin butane cartridges available from many outlets other than outdoor gear retailers is a cheap way of refilling canisters for warm weather use. While gas will transfer between the two canisters in a vertical orientation, G-Works informs us that if transferring from one of the thin bayonet type connector butane cartridges, then as the uppermost container empties, an angle of at least 45% is optimum, keeping the groove of the cartridge, attached to the adapter, facing downward. I must confess that I simply leave mine in the vertical position and do not seem to have had any issues so far.
Note that you cannot and should not attempt to transfer from a 100% propane canister (the dark green ones) into a standard backpacking type gas canister. Propane is a greater pressure, and requires the strong, heavy, steel containers in which it is sold. Standard canisters are made of lighter stuff and will rupture and possibly explode if you attempt to use one for pure propane. This is why even ‘winter’ gas canisters have a limited amount of propane in the mix.
It is easy to go wrong and make mistakes transferring gas. Three Points of the Compass is making no recommendation to you other than, if you do decide to use such a contraption, take your time and take care. If a canister is over-filled, don’t risk it, drain some gas off to bring it down to the correct weight. This can be done by simply turning the G-Works Gas Saver over and inverting both canisters and draining back into the donor canister, or another empty recipient canister, or by venting gas.
There are a great many films on YouTube showing how to use these gas savers. Some are frankly dangerous in what they purport, such as ignoring the dangers of overfilling with pure propane. This one is pretty good, and while I don’t agree with everything he says or does (for example, filling to capacity), it shows the procedure quite well.
G-Works produce some nifty little devices. I have used their lindal valve/propane bottle adapter in the past. Some other contraptions seem to be capable of doing everything other than waltz across the floor. Three Points of the Compass has no experience of them. Look at the G-Works Gas Solution 2 for example. I don’t think I will be buying that ambitious contraption.
The G-Works Gas Saver Plus is not cheap. But it is already paying for itself- added convenience when I top up a part-used canister, utilisation of cheaper gas (butane) for warmer months, and transferring the cheaper unit price gas from larger canisters to smaller ones. It also means that those part used canisters that come back from backpacking trips can now be emptied into just one.
Playing around with an ‘unofficial’ contraption like the G-Works Gas Saver could potentially result in a stuck EN417 canister valve. Unlikely and I have never experienced it. If it does happen, try screwing a stove on and off and that may reseat the valve. If not, then leaking gas is a BAD THING. Leave it outside, well ventilated and away from flames.
If you do refill a canister, record the new weight on the canister with a sharpie. I write weights in the dished base. Also note if you have changed from a propane (winter) mix to a pure butane fill so that you are aware that the mix is less suited to colder weather.
“DO NOT REFILL”
As I mentioned at the beginning, this procedure is hazardous, potentially dangerous. The variously branded gas canisters are pretty much unambiguous in their messaging on the side of their containers, even if the text is tiny and takes a bit of finding- “DO NOT REFILL”. Using a gas saver directly ignores the manufacturer instruction, on your own head be it…