Alleviate the Disadvantages of Fuel Canisters with this Simple Device
The advantages of isobutane canister stove fuel makes it extremely popular in the backcountry: clean burning, no spills, and ease of use. One of the major drawbacks I have found of canister fuel revolve around the inability to transfer fuel between canisters, resulting in partially used canisters piling up, and forcing me to carry multiple partially used canisters to avoid wasting fuel. On top of that, I often end up paying more per unit of fuel, as the cost is disproportionally higher in smaller canisters.
The G Works Gas Saver+ is a refill adapter for international standard EN417 gas canisters that is currently available on Amazon for $39.00. G Works Outdoor Solutions is a Korean company, with its site displaying a myriad of stove accessories rarely seen in outdoor specialty shops. Scarce company information, a foreign language used both on the site and included instructions, and the potentially dangerous act of transferring fuel under pressure, all combine to mandate a cautious approach. Note that anyone who buys or uses this item does so at their own risk since it probably hasn't been tested here in the US. Below is my experience with the product and is in no way a reccomendation for how to use this nor is it a replacement for the manufacturer's instructions.
Close visual inspection of the G Works Gas Saver+ reveals quality construction all around, with the anodized aluminum and brass unit’s CNC work both clean and detailed. Essentially it looks to be two Lindal valve adapters with a valve regulator—just like the ones found on stoves—sandwiched in between. There is a tiny “G Vent” that purportedly allows air to be evacuated so only fuel is transferred, theoretically preventing a buildup of air in the receiving canister after repeated fillings.
Although the instructions are in Korean, the use of the G Works Gas Saver+ was obvious to me. Simply connect the fuller of the two canister to the top, the less full canister to the bottom, open the valve and let gravity and the pressure differential force fuel into the bottom canister. I found the transfer can be made more efficient by placing the fuller canister in warm water and the other in ice water to increase the pressure differential. What isn’t so obvious when I tested it, was whether or not I could overfill the bottom canister.
Testing proved the G Works Gas Saver+ does indeed function in the two scenarios performed for this write up:
1) A brand new, full 110g (net fuel weight) canister filling an empty 110g fuel canister: 104 total grams of fuel transferred.
2) A partially full 220g canister filling a partially full 110g canister with 80g of fuel: 60g of fuel transferred, over filling the partially empty canister by 30g. The overfilled amount was manually vented off.
In both tests, the filling canister was placed in warm water and the filled canister in ice water for 5 minutes before transferring. Audibly, most of the transfer happens in the first minute but the canisters were left connected with the valve open for 3 minutes. A more complete transfer in the first test is plausible by waiting for a longer period of time and/or warming up the top canister and cooling down the bottom canister again. In retrospect, in order to avoid overfilling the canisters, the process should be monitored by periodically halting the transfer and weighing the receiving canister to see how much fuel has been passed on.
A few caveats merit mentioning. First and foremost, transferring fuel certainly can be dangerous and none of this is recommended by the manufacturers of the canisters. Infact, they probably denounce it. There may be legal issues with refilled canisters as well. The gas is flammable, explosive, and under pressure, so precautions are necessary. I was careful to only use warm water only and not hot to avoid higher, potentially dangerous, pressures. Different brands of fuel use different blends, and the canisters may be chosen for that blend’s internal pressure. For that rason I was sure not to mix fuel brands or their containers. Canisters, Lindal valves, and threads can wear out and leak, so I inspected them carefully between each use and only trusted one transfer per canister. I used a scale to know the canister and fuel weights to prevent over filling. When using the Gas Saver+ I knew I was solely responsible for my own safety.
Recycling the empty canisters requires that all residual fuel be removed and the cans punctured to ensure safety. I use the JetBoil “CrunchIt” tool, which I have found to do this in a safe and quick manner.
The G Works Gas Saver+ makes easy work of transferring canister fuel, eliminating waste and many of the inherent disadvantages. Partially full canisters can be combined to ensure enough fuel for the trip or to lessen the load to just the required amount. Purchasing larger fuel canisters and filling smaller ones ensures lower fuel costs as well.
Care must be taken during use, but after giving this system a go, I am done with the ever-increasing pile of partials, carrying multiple partials, and spending more on fuel than necessary.