Refilling Gas Canisters

[Hikin’ Jim]

> for example the ST-310 from Soto.

Now that stove DOES worry me! There is no way with a stock unit to prevent the canister from getting a LOT of heat from the flames, especially with a large pot. Frightening to me. George would have been horrified.

Alan is correct. There does appear to be a heat shield and the stove does sit up fairly high.

Who is George?

HJ
Adventures In Stoving

[Hikin’ Jim]

David Thomas wrote: I've been refilling propane for years, but never butane. We're ying and yang. Or Click and Clack. Or Mutt and Jeff?

Or Laurel and Hardy? ;)

David Thomas wrote: Anyway, you're welcome to shoot me your write-up if you want me to review it. I know you're not writing it for an audience like me (never do that!), but I'm happy to double-check it for you. I'm PM you my big mailbox address.

I got your PM, and I may take you up on that. So far, I've got some concepts but no track record.

As we've discussed on other threads, I've got all the components for refilling, including a Brunton Fuel Tool. Add an adapter (either propane or butane) to the Bruton Fuel Tool, and you've got a makeshift refiller.

I've successfully refilled CV360 butane cartridges for some time (these are used for small hand torches and Rando 360 stoves) using the above set up.

The problem occurs when I try to refill something like a PowerMax canister.

The majority of the gas comes spurting right back up along the "needle" of the Brunton Fuel Tool. What is needed is a way to seal the valve area around the needle of the fuel tool. A rubber sleeve and "O" ring would probably do it, but I never got around to trying that.

HJ
Adventures In Stoving

[David Thomas]

>"The majority of the gas comes spurting right back up along the "needle" of the Brunton Fuel Tool."

Okay, well that torpedos my plans for that adapter I just ordered. Can't ever have too many adapters around the house, but maybe I should impose on some of my EAA (experimental aircraft association) buddies for some shop time. They have some serious shops! And use a lathe to make an adapter from each fuel type to 1/8" pipe thread. Then I can match anything to anything and really get in trouble.

Have you tried chilling the receiving canister first? I never saw it anywhere, but it just made sense to me and I've always done it for propane-propane transfers. And keeping the donor cartridge at room temp or a little above.

Of course I have 3 freezers (kitchen freeze at 10-15F for ready reserve stuff, in-house chest freezer at -5F for the next month of stuff, and the deep freeze at -15F to keep the sockeye fillets as fresh as possible for as long as possible) plus it's been -25F outside for too long this week so I can play with fuel canisters without Kristin noticing.

Back to your Brunton refiller: So that little stem is just a bit too small in diameter? Like by a few coats of paint? Hint. Hint. Or a thin film of 2-part epoxy painted on?

[Hikin’ Jim]

What I was thinking of for my ad hoc refiller is something like this:

The rubber around the "needle" of the fuel tube would seal against the valve assembly. I think.

Have you tried chilling the receiving canister first? I never saw it anywhere, but it just made sense to me and I've always done it for propane-propane transfers. And keeping the donor cartridge at room temp or a little above.

Yes. If you put the receiving canister in the freezer for 1/2 an hour, it helps tremendously. I've also used a freezer gel pack and wrapped that around the receiving canister. That helps also, although it's more fiddle. One can also dunk the donating canister in warm water. Judiciously. Overheating the canister would be a problem of course. But if the water is tolerable to the touch, then it's fine.

For rapid filling I use the chill-the-recipient and warm-the-donor method. The easiest is to hook it up and let it sit overnight, but that only works if you have a nice refiller like the one on my blog. If you're using the Brunton Fuel Tool as a refiller, the warm/chill method is the way to go.

HJ
Adventures In Stoving

[David Thomas]

Interesting. You're going to seal the gap between the canister and the adapter. Whereas I was going to to make the "needle" a larger diameter. I don't have my adapter in hand yet, but I'll report in when I do.

[Hikin’ Jim]

I'm sure there's a way to get it to work.

I still think this type of adapter is going to be a lot more convenient, but that's a tricky adapter because there needs to be a pin in either end to depress the Lindal valves. Also the valve in the middle is needed or else you'll be spraying fuel all over as soon as you detach one or the other of the canisters.

Just how good are these EAA guys? :)

HJ
Adventures In Stoving

[David Thomas]

>"Just how good are these EAA guys? :)"

Jim, you get nervous when you light a new stove or transfer fuel.

These guys go up in airplanes they built from tubes and fabric or FG and resin. They're good or they're dead.

[Hikin’ Jim]

Addenda:

The type of adapter shown immediately above is referred to as an NN type. "N" apparently means 7/16" UNEF. "NN" means that both ends are threaded to 7/16" UNEF.

I don't know who makes them. I see them on two different websites in Japan:
Tumekaekun
Alva

I talked to my wife, who is Japanese, and she wasn't able to easily discern the manufacturer, but it's been some time (a couple of years) since I talked to her about those two sites.

HJ
Adventures In Stoving

[Hikin’ Jim]

These guys go up in airplanes they built from tubes and fabric or FG and resin. They're good or they're dead.

Yeah, I kind of figured.

Show them that adapter and see what they can do. That's the ideal.

Even though they're expensive I'm tempted to get one just so I can refuel the two Bernzomatic PowerCells that I managed to scrounge up. Still, probably close to $100 by the time shipping is paid. Ouch.

HJ
Adventures In Stoving

[Roger Caffin]

Hi Jim

Yes, your ad-hoc refiller would work. But put a little bit of pressure on the rubber.

What is meant to happen is for the thin spout to seal against the rubber flange just under the top of the metal nipple, but not all manufacturers have the same size hole in the rubber. You have met one which is too big.

Corollary: some combinations do not even need that O-ring you see in the base of most connectors. The rubber seals against the valve actuation pin, which is hollow in those cases. [eg CampingGaz and Powermax] But keep that O-ring in place, because you can be quite sure that whatever combination you take on your next trip will NOT seal!

Cheers

[Hikin’ Jim]

Thank you, Roger.

I noticed that I was able to fill some canisters with no problems at all whereas with others the majority of the fuel went shooting into the air.

HJ
Adventures In Stoving

[Mark Fowler]

I have had a heap of old gas canisters hanging around, not quite enough gas in them for my trips and I can only use up so many when playing with my stoves. When I purchased my Kovea Spider I noticed on the same seller's site this little device for connecting 2 screw thread canisters so I added it to the order.

I have just tried out my new "Gas Saver" device and emptied 2 largely empty Elemental 230g canisters into another one and a 3rd into a small 110 gram canister.

While I do not recommend, or even suggest, anybody refill canisters themselves, I reserve my right to immolate myself at a time and in a manner of my own choosing.

I also solved the problem of stopping the canister from being overfilled. I remembered a solution to preventing a canister from over filling being suggested on bpl. That is to tip the canister being filled at an angle to the vertical to maintain an air gap between the top of the container and the lindal valve in the canister. The suggestion was that a 20% volume air gap was required. It was also stated that calculating this would be a nightmare.

I have derived the angle by experiment rather than calculation for the elemental 230g canisters. They seem to be identical in profile to KMart's CampMaster 227g canisters and no doubt other brands as well – these are Australian brands but made in Korea like just about all of them. Please note that this angle is dependent on the profile of the canister. It is also dependent on the pressure in the two canisters being equal but this would normally be the case (unless you were filling with pure propane).

I knocked a second hole in an empty canister next to the valve. I filled the canister with water and weighed it – 633g. Subtract the canister 131g to get a volume of 502cc (1/2 a litre). We want an air gap of 20% or 100cc, so I poured out 100 grams of water. I then tipped the canister while aligning it with a protractor and read off 35 degrees just as water started to escape from the hole next to the valve.

[Jerry Adams]

To avoid overfill you could do it by weight.

Make sure re-filled canister is 13 ounces (or whatever) or less. Weigh the from and to canisters to see how much they each have and calculate if it's too much. etc.

[Ian]

I'm probably looking at this wrong but how does that device even work? My only experience with anything like this is using a cascading system of several O2 tanks at various PSIs at the fire department to fill up our O2 bottles after a call. Obviously with this system, if the receiving bottle has a higher PSI than the tank then you end up losing O2 back into the tank vs filling the bottle.

As a person who's lost his eyebrows and melted his eyelashes together a couple times, I really shouldn't even consider refilling a canister.

EDIT my asumption is that the device would equalize the presure between the two canisters if there wasn't a pump to transfer the remaining gas.

[Jerry Adams]

Take the one you want to fill and put it in freezer. When cold, take it out, connect canisters with the one you want to fill on the bottom, open valve.

[Larry De La Briandais]

Since you are transferring liquid so gravity will cause the liquid to flow "down hill". Having a higher pressure in the source vessel just speeds things up as the pressure differential helps push the liquid. This is different from the cascade system for transferring gas. In that case, yes, you can only transfer until the pressure equalizes.

[Ian]

That makes perfect sense. Forgot the obvious which is that this fuel is in a liquid state in the canister.

[Hikin’ Jim]

I have had a heap of old gas canisters hanging around, not quite enough gas in them for my trips and I can only use up so many when playing with my stoves. When I purchased my Kovea Spider I noticed on the same seller's site this little device for connecting 2 screw thread canisters so I added it to the order.

I have just tried out my new "Gas Saver" device and emptied 2 largely empty Elemental 230g canisters into another one and a 3rd into a small 110 gram canister.

While I do not recommend, or even suggest, anybody refill canisters themselves, I reserve my right to immolate myself at a time and in a manner of my own choosing.

I also solved the problem of stopping the canister from being overfilled. I remembered a solution to preventing a canister from over filling being suggested on bpl. That is to tip the canister being filled at an angle to the vertical to maintain an air gap between the top of the container and the lindal valve in the canister. The suggestion was that a 20% volume air gap was required. It was also stated that calculating this would be a nightmare.

I have derived the angle by experiment rather than calculation for the elemental 230g canisters. They seem to be identical in profile to KMart's CampMaster 227g canisters and no doubt other brands as well – these are Australian brands but made in Korea like just about all of them. Please note that this angle is dependent on the profile of the canister. It is also dependent on the pressure in the two canisters being equal but this would normally be the case (unless you were filling with pure propane).

I knocked a second hole in an empty canister next to the valve. I filled the canister with water and weighed it – 633g. Subtract the canister 131g to get a volume of 502cc (1/2 a litre). We want an air gap of 20% or 100cc, so I poured out 100 grams of water. I then tipped the canister while aligning it with a protractor and read off 35 degrees just as water started to escape from the hole next to the valve.

Mark,

I too had noticed that G Works canister refiller. I like it. I think it should be pretty safe when refilling like to like. What I mean by "like to like" is that refilling, say, a 70/30 butane/propane canister from another 70/30 butane/canister should be pretty safe, so long as one is careful to not overfill — which with your angled refilling should never happen. I think that's pretty good how you've worked out the angle. Of course I'd want to confirm by weight as well.

The one little thing that keeps tugging at the back of my mind is that a bit of water vapor might get inside the canister as one refills. That water vapor might cause some type of internal corrosion, corrosion that could not be seen from the outside. I haven't ever had this happen, though, and in the several years now that I've been refilling canisters with cheap 100% butane, I've never had an issue of any kind. I do limit refills per canister to about a dozen. After 12 refills, it's off to the recycle bin.

The advantage of course of the G Works adapter that you have shown is that one can refill with better mixes. With the refiller that I showed in the orginal post of this thread, one can only refill with 100% butane, a poor mix for colder weather. With the G works adapter, one can use a fresh 450g can of, say, 80/20 isobutane/propane to refill a 110g canister. The receiving canister should also have an 80/20 mix since the refilling is done in liquid form. An 80/20 isobutane/propane mix beats the heck out of 100% butane in colder weather although 100% butane is generally fine for temperatures above 50F/10C, and 100% butane is very, very cheap (at least here in Los Angeles it is).

HJ
Adventures In Stoving

[Mark Fowler]

You can achieve a 30% propane 70% butane fill by sorting out the angles. When the canister is vertical (on it's side you) should get a 50% fill so turning it to say 5-10 degrees off vertical should achieve about a 60% fill. For this part of the fill use butane although I have found some very cheap 220g isobutane mix canisters. Turn to 35 degrees and fill with propane up to the 80% level. 33% propane, 67% butane fill.

For the propane filling Kovea produces a propane bottle to screw lindal valve adapter which has a pressure regulator in it should overcome most of the high propane pressure issues.
http://www.ebay.com.au/itm/KOVEA-LPG-ADAPTER-for-over-3kg-LPG-Gas-Tank-MADE-KOREA-/140906972077?pt=LH_DefaultDomain_0&hash=item20ceb5c3ad#ht_6132wt_1163

I am going to have a play with this now we are moving into winter down here. Less problems with canisters getting too hot.

Standard disclaimer.

[Hikin’ Jim]

lol.

Yes, I thought of that too. If you get a butane adapter like this:

You can connect it to the refiller you linked to:

and fill up to 70% with butane.

Then hook up a propane adapter like the one you pointed out:

and fill the remaining 30% with propane.

Dangerous as all get out if overdo it, but the capability is there. Safer I think to just transfer from one standard backpacking type canister to the other with pre-mixed blends.

Of course, for the very brave, you can "spike" your mix with extra propane. If you keep the canister cold, it should be OK, but you'd want to be EXTREMELY assiduous about keeping that canister cold. Forget and leave it in your pack when you come back to your nice warm home, and… Well, it might be bad anyway. Opens up a lot of possibilities and a lot of dangers at the same time.

Now, I can make my own winter blends though. Quite interesting.

HJ
Adventures in Stoving

[Jerry Adams]

I saw "Burton" butane 220g canisters at Fred Meyer for $2.50

I used those last summer and they worked fine above 35F or so

Makes refilling less cost effective

[Mark Fowler]

When refilling a part used blended fuel canister from another part used canister is that the propane percentage, and to a lesser extent the isobutane component, are decreasing as the canister is used. What started out as a 30% propane canister becomes when half full about a 10% propane mix. Thus decanting part used canisters will lead to a rapid reduction in the percentage of propane. This is less true if you always run in inverted mode. For summer this doesn't matter too much, but for winter keeping the propane percentage up is far more important.

I would only use the proposed method when I start with a totally empty canister (known propane content of 0%) and it would need monitoring by weighing the canister after filling with butane and also after adding the propane to ensure the canister is not overfilled. I also agree that the canisters should only be refilled a few times. I plan to discard after 10 refills or if the canister shows any sign of rust or damage.

I terms of payback, 230g canister cost on average $10 in Australia. I purchased a case of isobutane blend 220g canisters for $0.67 per canister so every refill saves me $9.30. I only need to refill 3 times to break even on the cost of my gas saver.

[Hikin’ Jim]

I saw "Burton" butane 220g canisters at Fred Meyer for $2.50

I used those last summer and they worked fine above 35F or so

Makes refilling less cost effective

Jerry,

Are those standard screw threaded canisters? Directly compatible with backpacking stoves? if so, that's a heck of a price. Can't touch a 220g canister here in Los Angeles for less than $5.

I get 227g butane in the bayonet connector canisters for $1.00 at the dollar store, but 110g canisters are $4.00 at the cheapest. If I refill with butane, my cost goes from $4.00 ea. to $0.50 ea. I've recovered the cost of my refiller many times over.

Still, to be honest, it's a bit of a hassle to refill. Refilling to save money may not be all that attractive to most. I like to experiment with stove related things (if that wasn't obvious by now). :)

The idea however of being able to "spike" a canister with a higher percentage of propane, now that's a very attractive idea to me. If one were assiduous about not letting the canister get hot, higher percentage blends of propane would be reasonably safe. Higher percentage propane blends means I don't have to take a white gas stove. That could be nice.

HJ
Adventures in Stoving

[Jerry Adams]

Yeah, those are regular canisters like Giga Power or MSR.

I used a couple last summer and they worked fine with my Pocket Rocket.

Regular 220g canisters of iso-butane cost $5.50 I think. Price keeps increasing. $2.50 for butane seems like a deal. As long as you won't be using it below 30 or 35 F.

[Hikin’ Jim]

When refilling a part used blended fuel canister from another part used canister is that the propane percentage, and to a lesser extent the isobutane component, are decreasing as the canister is used. What started out as a 30% propane canister becomes when half full about a 10% propane mix. Thus decanting part used canisters will lead to a rapid reduction in the percentage of propane. This is less true if you always run in inverted mode. For summer this doesn't matter too much, but for winter keeping the propane percentage up is far more important.

Agreed. For summer use, simply consolidating partial canisters into a single full (or nearly full) canister makes a great deal of sense and should be pretty safe and hassle free. If the sum of the weights of the gas in the partials is no greater than the capacity of the receiving canister, then overfilling is impossible and the process is intrinsically safer.

When I refill, I often transfer gas from 227g bayonet connector 100% butane canisters to 227g threaded connector backpacking canisters. Overfilling is impossible.

I would only use the proposed method when I start with a totally empty canister (known propane content of 0%) and it would need monitoring by weighing the canister after filling with butane and also after adding the propane to ensure the canister is not overfilled. I also agree that the canisters should only be refilled a few times. I plan to discard after 10 refills or if the canister shows any sign of rust or damage.

Yes. I would only add propane to a blend where I started with an empty canister and then added butane or isobutane of a known quantity to that empty canister. Adding propane to a canister already containing an unknown quantity of propane could be quite dangerous — even if one were to stay within the capacity limits by weight of the canister. A fuel blend with an unknown percentage of propane could easily have a higher vapor pressure than the canister is rated for. That might be, well, bad.

I terms of payback, 230g canister cost on average $10 in Australia. I purchased a case of isobutane blend 220g canisters for $0.67 per canister so every refill saves me $9.30. I only need to refill 3 times to break even on the cost of my gas saver.

Yipes! That's roughly double the cost here where I live. That's very nearly robbery.

I take it the case of isobutane canisters you bought are cylindrical, yes? If they were the typical dome shaped canisters, then there would be little incentive to transfer the contents. They would be fine though for a remote canister stove, but only in warm weather since cylindrical canisters would be difficult to invert for cold weather.

That's really nice that you can get isobutane there in Australia in such affordable canisters. I've never seen anything like it here in the US. We have 100% propane, 100% butane, and that's about it (other than backpacking specific canisters). Isobutane is simply unavailable.

HJ
Adventures In Stoving

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