Of course it's possible to refill backpacking type gas canisters. But what are the real risks? What are the practicalities? Is it even worth it?



Please join me as I explore Refilling Gas Canisters

HJ

I would advise against refilling gas cylinders that are intended to be disposable.

When a container is filled, it is most important that it is not completly full, in order to allow room for expansion.
If the container is overfilled, then even a modest increase in temperature may cause it to burst.

There is also the risk of filling a butane container with propane or with a butane/propane mix which has a higher pressure.

The risks may be somwhat reduced by
Only filling on a hot day, in order that subsequent temperature increases are unlikely.
Only partialy filling
Keeping re-filled containers outdoors
Not keeping them long term.

Refilling should be done, if at all, outdoors due to the risk of leakage.

The best advice though, IMO is dont.

AFAIK in some states of the USA it is a federal offence to transport refilled disposable gas canisters.

I wonder why there is no adapter for the 110 g butane canister: a folding three-legged wire frame to replace the backpack canister as a stove support and a flex tube to attach the cheap butane canister directly to the stove?

Not a very good idea. If I really want to save money I will simply build a campfire. I don't do that much any more, but I have cooked many a meal over one.

Somebody filled the canisters in the first place.

How did they do it?

Copy them.

Most likely, it isn't economically feasible to have the same hardware and procedures they used. It certainly isn't feasible for me to pressure-test and recertify them at home.

Adam,

I wonder, did you read my blog post at all?

I specifically addressed overfilling. I specifically addressed the proper mix of gasses. I specifically addressed safe vapor pressure.

If it varies state to state, then it is not a Federal offense. The US Department of Transportation (DOT) regulates interstate commerce. Transportation across state lines is within their jurisdiction, and my understanding is that DOT does prohibit such transport. I so state in my blog post.

HJ

Do you mean something like this: Three Legged Butane Adapter?

I find that it's easier (at least for me) to do the fiddling at home rather than fiddling with an adapter in the field. Also the adapter weighs more (78g) than many stoves (MSR MicroRocket, 73g), so weight wise it doesn't appeal to me. But that equation will be different for different folks.

However, if one were out on a long distance hike, carrying the adapter would mean that one could use either type of fuel, which might be an advantage. I've seen the butane canisters in a lot of grocery stores, stores that I've never seen a BP'ing type canister in.

HJ

Well, it's definitely hiking with the training wheels off. You can do more, but you can also get yourself into a lot more trouble.

I ran everything by an engineer (one who burns hydrocarbons for a living) and a physicist. Clean bill of health. There are dangers, but not inordinate given the type of gas used, the quality of refilling rig used, and the procedures used.

HOWEVER, risk assessment is a very personal thing. If there's any doubt in anyone's mind, then I wouldn't do it. A lot of the time, I post to show what can be done. Most people will never need to use many of the techniques I'm showing.

I'm working on some stuff for extreme cold weather right now (below -35F/-37C). Just going out in that weather is in and of itself risky.

HJ

Why would anyone be willing to play with fire like this (pun intended) to save a few cents? It boggles my mind. If the few cents you might save by refilling something not meant to be refilled are that important to your financial situation, I would recommend using an alcohol or wood burning stove instead of a pressurized gas one.

But if you insist on refilling your cannisters, be sure and yell "Hey y'all, watch this!" before you begin. That is the universally recognized warning phrase that you are about to make your bid for a Darwin Award. Others can clear the area accordingly.

Make sure you have a few beers first. I believe that is customary in such cases.

Actually, in practice, I find it no more dangerous than hooking up a stove. Certainly this is less dangerous than using white gas which many people do without giving it a second thought.

HJ

I am reminded of a saying from my esteemed brother, who retired to Bemidji, MN, to escape the innervating heat of Houston, TX - "There is no such thing as bad weather - only bad clothes."

He definitely has a point; forty below is just fine, as long as you are suitably dressed, aware and thinking straight.

As for a fuel in those conditions, what's the issue? Go with white gas or kerosene.....Not as superbly convenient as a canister stove, but it will get the job done. Again, you must know what you are doing, but that is true in most of life's situations.

Well I've got to agree with that. I remember back decades ago I would be holding my little SVEA 123R stove in my hands trying to warm up the fuel inside enough so it sprayed out the top so I could light the stove. In retrospect, lighting a white gas stove with (occassionally) fuel spilled on my hands was not the brightest move I ever made. Someone up there must have been looking after me!

So we'll just call me "fire-hands Dave" and we can call you "BLEVE Jim"!

This is becoming an interesting demonstration of perception of risks. What is actually more hazardous - white gas or refilled canisters? I wonder if any hard data exists?

Certainly you can get into trouble with any kind of stove or fire if you are clueless.....

Most definitely. I don't do so much hiking/backpacking as I used to, but I have switched from white gas over to alcohol (Trangia) and wood burning. My switch was not necessarily because of safety, even though alcohol and wood are probably the safest of the inherantly unsafe fuels. But because I now think alcohol and wood are just "cooler". "Cooler" as in "nifty", "neat", "swell", "peachy", etc.

BTW, my statement below was intended to be a joke, not a comment on which fuel is better/safer!

The issues for gas vs. liquid fuel in extreme cold are in general two fold:
1. Mechanical reliability
2. The dangers of priming when tent bound.

I recently read of an Arctic (Antarctic?) expedition that was using a liquid fueled stove. They brought three pumps for the one stove. Two out of the three pumps failed. They made it, but had that last pump failed, they would have been in a world of hurt. The problem? The "O" ring that seals the fuel line to the pump got so cold that it no longer sealed properly. If you want to talk about danger, try lighting a white gas stove that is sitting in a puddle of its own fuel. Generally, gas stoves have greater mechanical reliability than liquid fueled stoves.

Gas stoves don't require priming. When it's -40 and there's a howling gale out, the only reasonable place is in your tent. You live there for 24 hours a day. You cook in your tent. Dangerous? Of course. But it's even more dangerous to open that door. Now, go ahead. Prime your liquid fueled stove. In your tent. And you were saying refilling gas canisters is dangerous?

The dangers of refilling are real, but put the dangers into perspective. Working with liquid fueled stove is as or more dangerous.

HJ

Yes.

Now, we all "know" that refilling gas canisters is "dangerous." But white gas stoves have been around for ages. We're following the manufacturer's recommendations, so it "must" be safer, yes? Yes? Well? Hmm.

Now, take something like a Svea 123/Primus 71/Optimus 8R. Question: What stops that stove from over heating? YOU do. The only control on that stove is you. If you let the stove get too hot, the SRV will "pop," and you'll get a flamethrower. And you were saying that refilling canisters is unsafe? Really?

OK, maybe that's an unfair comparison. The stoves I named above are all older stoves. How about a more modern stove? MSR just released the Whisperlite Universal this very month. Question: On a Whisperlite, what stops the fuel from flowing all over the place? YOU do. The only control on that stove is you. If you leave the valve open, the entire contents of the fuel tank will pour all over the place. Anyone got a light? What stops you from striking that match? YOU do. I recently saw a Boy Scout practically immolate himself and his dad with a Whisperlite. They hadn't a clue. Flaming white gas everywhere. You never saw a bunch of scouts move so fast. And you were saying that refilling canisters is unsafe? Really?

What prevents overfilling a gas canister during refilling? YOU do. It's really no different than working with white gasoline stoves. You are the safety. Don't screw up. That advice goes for a lot of life. Welcome to the real world.

HJ

There goes my dream of fame and fortune..................

Geez, Jim - you are strongly implying that one must take responsibility for one's actions. What an outmoded concept in today's environment!

I guess the problem is that if one is refilling canisters they have crossed the bright line drawn in the sand by lawyers, and boldly violated the words printed on the canister: WARNING; DO NOT REFILL. Even if it isn't really valid, refilling does leave you hanging out on a limb.

From a more realistic technical perspective, I am just a wee bit cautious about refilling a container that is designed, manufactured, and marketed, as well as plainly labelled, as a single use device. Your experience is quite interesting, but I am going to have to take a bit of time to get my head around the concept. And then I still have to deal with the basic ease of buy, use, and toss (well, recycle), and staying firmly within the lines....

OT but sorta related. Hikin_Jim's post and blog articles on butane adapters, and refilling canisters with butane made me take a look at the stoves designed for that can. The stoves available on Amazon and REI mostly look the same, one burner, can sits in the compartment on the right-hand side. Mostly good reviews.


Not exactly designed with backpacking in mind, but it might make for a great emergency stove. Relatively inexpensive and fuel cheap enough that HJ finds ways to use it in stoves not designed for the cans.

I'm terribly sorry to have made such an outrageous suggestion. What was I thinking?

Remember! Lawyers know more than you do about the outdoors. DO NOT consult people who have experience in the outdoors. Lawyers are always your best guide in all areas of life.

Yes, I had to think about it too. But consider:
Canisters have Lindal valves. What else has a Lindal valve? Well, hair spray, Lysol, spray paint, etc, etc. What's the propellant? Often it's... wait for it... a hydrocarbon. Butane in other words. So those valves are in all kinds of "canisters" in use every day. How many times is a valve used in a can of hair spray?

Or consider this: How many times is a valve used on a 450g canister of gas. Probably at least four times the number of times on a 110g canister of gas. That tells me right there that the valve on a 110g canister of gas is good for at least four refills. But now consider usage. Some people are soloists who just boil water. They're going to hook up and unhook that valve dozens of times compared to someone who is cooking for a family and is doing "real" cooking. In other words, those valves have to accommodate a wide range of uses. Those valves are very rugged. Using one 12 times in refilling is fairly conservative.

Now consider this: In canister failures, what usually fails? Well, the bottom inverts (goes from concave to convex) first. In other words the base of the canister is the typical point of failure, not the valve. That valve is actually quite robust.

The main thing I'm worried about is rust or corruption getting into the valve, not the valve itself per se. I visually inspect the canister, and I always keep the lid on the valve when the canister is not in use.

HJ

For what its worth, I have had the valve in a 110g canister fail. Probably used it half a dozen times, and after the last time (still half full), it wouldn't close. Tried reattaching the stove to try and re-seat the valve, didn't work. Luckily I was at home, so I just set the can away from everything until it emptied itself. Not a huge deal, if I was camping I just would have left the stove attached (inconvenient, but would have saved the gas).

Yep. Like anything mechanical, they can fail. I had one stick open on me one time too. However, out of all the gas stoves I've used, I've had one and only one failure, and it wasn't on a canister I had refilled.

Putting it into perspective: Maybe I'll post photos some time, but I've had at least a dozen failures with pumps on white gas stoves, one of which resulted in a fire.

Gas stoves are WAY more mechanically reliable than liquid fueled stoves.

HJ

I've got a camping gaz refill adapter from the same seller in Japan. I started refilling from the butane cans as the CV270 canisters are now impossible to get where I'm at and there are times when a CV470 is too big.
I think Jim has written out quite extensively the hows and whys and the safety precautions. I've not had any issues so far.

You make an excellent point. The last time i had to resort to a campfire for meal preparation was the result of pump failure on my backpacking stove.

Which raises the issue - How about using the traditional non-pump enabled Sveas or Primuses (Primi?) As I remember, the instructions say to preheat them either with body heat or a separate alcohol priming solution. Of course, we never did that - just sloshed a very tiny bit of white gas into the priming cup and lit'er up.

But would a properly primed Svea be safer than a pump unit? I suppose the greater question is - what is the safest, most fool proof backpacking stove. Of course, safety is relative here, since we are literally playing with fire....

Yeah, like day and night. And Mon - Fri and weekends. lol. I think the 450g CV470's are too big to carry on all but extended trips. And maybe for snow melting. Those suckers are BIG.

Thanks.

HJ

Oh, boy. Tough question.

In terms of safety, I'd say hexamine (e.g. ESBIT) stoves are probably the best. They can't spill, they aren't super hot, and you can just blow them out. Of course hexamine is the most expensive fuel, has limited heating power (it's kind of weak), is very vulnerable to wind, leaves some sticky goo behind on the bottom of your pot, and there's no adjusting the flame (it's either on or off).

For new users, say a young Boy Scout or Girl Scout, I usually recommend a canister gas stove. In terms of safety, they can't spill, there's no priming, and they're very reliable mechanically. In terms of ease of use, they have relatively good wind resistance, they have good power, and the flame is very adjustable.

Gas stoves are pretty good, but you can do screwy things with a gas stove. Like too tight of a windscreen (although I generally don't recommend windscreens to new users). Or say you've got the whole troop cooking. Together. On one picnic table. All those stoves so close together, radiating heat to one another. That could be bad.

And there's always cross threading. And very reliable still isn't 100% reliable. I've had a gas canister valve jam open when I removed the stove. NEVER CHANGE CANISTERS NEAR A HEAT SOURCE OR WHEN THE STOVE IS STILL HOT.

After gas stoves, kerosene stoves. If you're going to use liquid fuel, kerosene is definitely safest. It's actually hard to get kerosene to burn. Kerosene stoves are basically like white gas stoves but with a safer fuel.

After kerosene, alcohol stoves. Alcohol stoves don't burn very hot by comparison to petroleum base fueled stoves, but you can still burn the heck out of yourself. Alcohol stoves can and do spill, and that can be very bad. Most alcohol stoves have no way to be shut off other than burning themselves out. And a lot of people have gotten burned by the invisible flames. Particularly dangerous is adding fuel when you think the flame is out but it's not.

Then white gas stoves. You can really screw up priming, and it's possible to over-pump a stove. Stoves like a Svea 123 or Primus 71 don't have a pump, but the flame is mere centimeters from the fuel. Generally, I think the remote style stoves are a bit safer (like a Whisperlite) because the fuel is separate from the flame, but then again a Svea 123 or Primus 71 doesn't have a pump, so maybe that's something of an equalizer.

Last place is wood stoves. You have to feed them. Mostly that's done by hand. You're hand is made out of flesh. Flesh burns. This is not a good combo. I've also had a number of injuries just breaking up wood for the fire. And of course, depending on your set up, there's the risk of burning the whole forest down.

So, there you have it, HJ's off the cuff take on stove safety.

Summary (in order from safest to least safe):
1. Hexamine
2. Canister gas
3. Kerosene
4. Alcohol
5. White gas
6. Wood

I think those are all the major fuels, although maybe I should include yak dung and other exotics.

HJ