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Monday, January 23, 2017

The G-Works Adapter – 100% Propane for Backpacking

Backpacking gas canisters are for backpacking and car camping canisters are for car camping, right?  Well, yes, generally that's true – but not if you have a G-Works adapter.
A G-Works propane adapter connects a backpacking stove to a car camping type 100% propane canister.
A G-Works adapter screws on to the top of an everyday ordinary Coleman type 100% propane canister, the kind that are used for car camping, picnics, BBQ's, etc.  The other side of the adapter is a 7/16" UNEF threaded connector – just like the one on the top of a backpacking type gas canister.  You screw in 100% propane on one side of the adapter and your backpacking stove on the other, and, voila! – you're cooking on 100% propane.

Now, the big 16.4 oz/465 g 100% propane canisters are pretty heavy and bulky.  Why use them?  Well, see my list of reasons, below.

However, note, that there are a lot of techniques and technologies that can help you use regular backpacking canisters in cold weather; see Gas Stoves in Cold Weather – Regulator Valves and Inverted Canisters.  You can also use a liquid fueled stove in cold weather.  This adapter is just another option.  Each person should evaluate his or her own circumstances and preferences and choose accordingly from among the options.

Regarding the weight of the 100% propane canisters:   I have a couple of Coleman brand 465 g canisters of 100% propane in front of me.  They weigh about 850 g each.  The weights vary, but the lowest I've seen for a full 100% propane canister is about 840 g.  By contrast, a 450 g Jetboil brand backpacking type canister weighs 660 g.  That's a minimum difference of about 80 g (roughly 3 oz) for comparably sized canisters.  Some Coleman 100% propane canisters weigh 870 g.  That's about about 110g (about 1/4 pound) more than a comparable backpacking canister.

Is the weight worth it?  Well, that's something you're going to have to decide for yourself.  Read the rest of the post and see if benefits are sufficient to justify the weight of the heavier canister.
A car camping type canister of 100% propane
16.4 oz/465 g net fuel weight
Cautions
High pressure!
Now, remember, the vapor pressure of propane is WAY HIGHER than a normal backpacking canister. Start on low, and open up gradually the valve on your stove.  This is a big boy/big girl, grown ups only, type adapter.  There's no built in safety.  YOU are the safety.  In order to operate this safely, you have to control the gas flow with the valve on your stove.  Turn it up too high, and you might blow out the flame.  If the flame goes out, you've now got a highly flammable, potentially explosive gas rushing toward the red hot metal of your stove. I'm thinking maybe that's not such a good idea – if you get my drift.  So, BE CAREFUL.

Do not tip over!
Also, DO NOT tip the canister over.  The canister needs to be upright.  If you lay the canister on it's side, you're going to be feeding liquid fuel into the burner instead of gaseous fuel.  Don't lay the canister on its side UNLESS you've a) got a remote canister type stove with a generator (pre heat device) of some type and b) your stove is good and hot.  If you don't know what a generator or pre heat device is, don't lay the stove on its side!  You could get a huge yellow fireball.  This is highly dangerous.  Don't do it.

Not recommended for regulator valved stoves above 40 Fahrenheit/5 Celsius.
If your stove is equipped with a regulator valve, I would not use this adapter in cool, warm, or hot weather.  Why?  Well the regulator in your valve is not built to handle the high pressure of propane.  Can your stove's regulator handle the high pressure of propane?  I have no way of knowing – so don't do it.  If you use 100% propane on a regulator valved stove, you could damage the regulator.  If the regulator fails, how are you going to control the flow of gas?  I'm not sure exactly what would happen if your regulator failed while your stove was lit, and I don't want to find out.

Of course, in colder temperatures, high canister pressure is hardly a problem.  At temperatures around 40 Fahrenheit/5 Celsius, 100% propane has roughly the same vapor pressure as an 80/20 isobutane/propane mix at 110 F/43 C.  Your stove should be able to handle such pressures. You should be pretty safe so long as you start with the stove on low and turn it up slowly.  Particularly below freezing, a regulator valve equipped backpacking stove should be fine.  However, note the effects of altitude.  The pressure inside the canister relative to the outside air will become greater at higher elevations.  For every 1000 feet in elevation gained, you should deduct 2 Fahrenheit degrees from my 40 Fahrenheit estimated safe temperature limit.  That would be about 1 Celsius degree for every 300 m.  For example, at 10,000, instead of a 40 Fahrenheit safe limit, you would want to not operate a regulator valve stove above 20 Fahrenheit.  

The vast majority of stoves do not have a regulator valve, but you should check with your manufacturer as to whether or not your particular stove has a regulator valve.

Here are some stoves with regulator valves.  Do not use this adapter with these stoves in cool (above 40 F/5 C), warm, or hot weather.  Use only in cold weather (below 40 F/5 C).
  • Jetboil Joule
  • Jetboil MightyMo
  • Jetboil MicroMo
  • Jetboil MiniMo
  • Jetboil Sol
  • MSR Reactor
  • MSR Windburner
  • Soto Micro Regulator
  • Soto WindMaster
That's all the regulator valved backpacking type stoves I can think of off the top of my head.  Remember to check your stove to see if it has a regulator valve before using this adapter.  Usually it will say on the manufacturer's website if a particular stove has a regulator valve.

Reasons to use this Adapter
1.  Cold weather.
Why 100% propane?  Well, for starters, cold weather.  Butane, which is often the majority component in backpacking gas canisters, vaporizes at 31F/-0.5C.  That's really not all that cold.  Not only that, but you have to be about 20 Fahrenheit degrees (10 Celsius degrees) above the vaporization point before you have consistently good pressure.

Propane on the other hand, vaporizes all the way down to -44 Fahrenheit/-42 Celsius.  That's cold!

Vaporization (Boiling) Point
 n-butane    -0.5°C    31°F
 isobutane    -12°C    11°F
 propane      -42°C   -44°F

And yes, I know they usually blend in some isobutane and propane into the typical backpacking gas canister, but still, nothing beats 100% propane for cold weather.

NOTE:  If you're going out in really cold weather, TEST YOUR SET UP FIRST.  Propane is typically not pure (well, maybe if you work in a laboratory or something).  The temperatures listed above are based on pure propane which you can't buy at least in the US, so you're not going to get quite the good cold weather performance that you might expect.  The propane typically sold in the US conforms to the HD5 standard which is as follows:

  • Minimum 90% propane (no less than 90%)
  • Maximum 5% propylene (no more than 5%)
  • The remainder is comprised of "other" petroleum based gasses
The "other" might include methane, ethane, isobutane, butane, etc., some of which will give you less performance in cold weather, others of which will give you better performance.  So, the number -44F/-42C is something of an approximation, depending on exactly what you've got in the canister.  Still, 90% minimum propane is going to be significantly better than any backpacking canister's mixture which is typically no more than 30% propane.  And remember that you need to be about 20 Fahrenheit degrees (10 Celsius degrees) above the vaporization point before you have decent pressure.  Of course, one can always warm the canister by various means, and so long as isn't warmed to the point of being too hot to touch, it should be safe while giving one good pressure.


2.  Instantly "winterize" your existing stove. 
With this adapter, you don't have to shell out the cash for a dedicated winter stove.  Here's what I mean:  Say you're basically a summer camper.  Most people are.  But every couple of years you get a wild idea and go out when it's cold.  A stove is pretty close to a necessity on a winter trip.  But do you really want to spend the money on an expensive stove that you're only going to use every couple of years?  No, of course not.  No problem.  Just get this little adapter, and voila! you instantly have a winter capable stove.

3.  Outlying areas (no backpacking canisters available).
In a lot of outlying areas, specialty items like backpacking canisters may simply not be available.  I know guys who have hiked in rural New Mexico where they just couldn't find backpacking canisters, but, walk into a hardware store or gas station, and, there they are:  100% propane car camping type canisters.  Having this little adapter might mean the difference being able to do a given trip – and having to just go home.  This is particularly true if you have to fly in for a given trip and cannot take canisters from home.

4.  Natural Disasters.
You could look at this adapter as $20 worth of cheap insurance.  This adapter opens up a whole new fuel supply for your backpacking stove.  The ability to boil water for drinking can be critical in times of natural disaster.

5.  Cheap fuel.
Another reason for buying 100% propane is that it's typically cheaper.  I've seen propane for as cheap as $2.50 (USD) per canister.  About the cheapest you'll find for the equivalent amount of backpacking gas is $7 or $8.  That's a HUGE price difference.  Why?  Well, think about it.  For every backpacker, there are hundreds of car campers, hunters, picnickers, and back yard barbecuers.  The economies of scale just aren't there for backpacking canisters.

6.  Trailhead camping – or just using your backpacking stove for everything.
You might also want to bring 100% propane to cook your supper and/or breakfast if you spend the night before a backpacking trip at the trailhead.  That way, you start with a 100% full backpacking canister for your hike.  Or heck, maybe you just want to own one stove, and your backpacking stove is it.  You use backpacking canisters when backpacking, but when car camping, picnicking, etc. you just use cheap propane, and who cares about the weight when you're using your car, right?

Other Compatible Canisters
Of course there's no reason that you have to restrict yourself to the big, fat 16.4 oz/465 g propane canister.  The 14.1 oz/400 g canisters will work just as well and may be more packable.  For a remote canister stove that can handle liquid feed gas (inverted canister type operation), this might be a nice option.  Heat the stove up with the canister upright, then when the stove is hot, lay the canister on its side for liquid feed.
A 14.1 oz (400 g) propane canister

Really, any fuel canister with compatible threads could be used – but is it a good idea?  For example, the little 5.45 oz/155 g Bernzomatic QuickFire canisters appear to be compatible.  This has NOT been tested with this adapter or with a backpacking type stove is NOT recommended.  Note that the gas contained is NOT pure propane.  Bernzomatic QuickFire canisters contain MAPP gas which does have propane in it but also has a high percentage of propylene.  Propylene burns at a much hotter temperature than straight propane.  What will this high heat do to your stove?  I don't know, but I do know your stove is not built to handle that kind of heat.  I wouldn't do it, but it's up to you.  If you decide to go against my advice, exercise extreme caution with any non-propane canisters.
A Bernzomatic QuickFire 5.45 oz/155 g canister of MAPP (high propylene content) gas.
This has NOT been tested and is NOT recommended with this adapter.
Weight
Some of you may remember my post a few years ago on the Kovea propane adapter.  The Kovea propane adapter is a great little adapter, but it weighs 105g – that's nearly a quarter of a pound!  By contrast, the G-Works adapter weighs 33 g, about 1.2 oz – only about one-third the weight of the Kovea adapter.  In other words, the Kovea adapter weighs roughly triple what the G-Works adapter weighs.

Using the Adapter
OK, so how well does the darned thing work?  Pretty darned well, actually.  Here's a video demonstrating its use:
  
Compatible Stoves
There is a rim around the threads where your backpacking canister attaches.  I used a Kovea Spider stove with my G-Works adapter, and it worked great, but some stoves with a really wide base might not work.  The rim around the threads is about 25 mm outside diameter and about 21 mm inside diameter.  Again, however, I would not recommend that this adapter be used with any regulator valved stove.

The G-Works adapter is made in Korea.  Generally stoves made in Korea work well with the adapter if they fit within the rim.  I've had reports of some stoves from China where the pin on the stove was too short to open the valve on the adapter.  A lot of stoves are made in Korea including some MSR, Snow Peak, and of course Kovea stoves.

Price and Availability
They're available on e-Bay for about $20 although there may be better deals out there.  Amazon is a lot more expensive.

OK, that's it.  That's my presentation on the G-Works adapter, a very nice piece of gear.  Thanks for joining me,

HJ

46 comments:

  1. I think I am right in saying that some backpacking stoves should not be used with propane solely.

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    1. Alan, I'm not aware of any. You just have to turn down the flame using the valve on the stove. The way that propane combusts isn't particularly different from other commonly used gasses for backpacking stoves. The only difference is the pressure. So turn it down.

      HJ

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  2. I wish I could remember where I had read it or if I was just mistaken. I trust your knowledge Jim so I will go along with you. Keep up the good work your posts are extremely helpful. Thanks.

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    1. Hi, Alan.

      You definitely can get into trouble with 100% propane if you turn up a stove too high. The vapor pressure is much greater with propane. It's generally fairly safe -- PROVIDED that one is careful. Open the valve slowly.

      HJ

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  3. Good info. Probably not stated because it's obvious, but if weight and space are a concern, these 16-oz propane canisters are large and heavy compared to the isobutane canisters, but for some trips might be an okay option even before considering the temperature and availability advantages.

    Some might use a canister-mounted stove rather than a remote stove, which is doable, but I recommend securing the canister in some fashion. It will be very tall and tipsy otherwise.

    ReplyDelete
    Replies
    1. Yes, you are absolutely right. These canisters are heavy beasts, generally to be avoided. However, if you're headed out into -10 F or -20 F weather, that weight might be the best investment you'll ever make. :)

      But, yeah, for most trips, just go with a propane-isobutane mix like MSR's backpacking gas canisters. I've got ideas for cold weather for those as well here on the blog. Look at December 2016.

      HJ

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  4. Another possible use for this device? For the person who just occasionally winter backpacks and does not want to invest in an inverted canister stove or white gas stove. Though this adapter is $45 on Amazon vs $17 for the older, but heavier one. A whisperlite is now $88 on Amazon. Not much more ,really vs the adapter. Personally, if I was on a budget and could not afford a dedicated winter backpacking stove, I'd take the weight penalty and buy the older one for $17. Always a trade off...

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    1. I see below that you caught it that these are on eBay for $20 bucks -- basically the same as the 3X heavier Kovea model.

      Yeah, good point. For a person who just wants to use their summer backpacking stove infrequently on a winter trip, this is a nice piece of gear. Spend $20 on a little 1.2 oz adapter rather than $80 or $90 on a dedicated winter stove. Good point.

      HJ

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  5. ..and I see it is on ebay for $20. NM. :D

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    1. I've integrated your point about a non-dedicated winter stove into the blog post. Thanks for that.

      HJ

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  6. We had a tough time last year with a hurricane in October in the southeast USA and lost power for days. I used my stove with canisters and rationed my fuel so I would not run out. If I had this adapter and a tank available I would have been in much better shape. ( And I own a kovea spider already!) So it a good solution to keep in mind for storm events.

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    1. Tonio,

      That is an excellent point. I may add that to my review.

      HJ

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  7. Excellent read I mix my own because the weather is so cold in Labrador I use 50/50 and I use it for my light too my small one mantle works great still lights in the shed did try with 100 propene but find it too powerful for my over night camping in the morning I use the 100% propene with the Ultra Blue canisters I found works great and can refill them sent link to show the canister it has a nylon wadding in it no idea want it dose any ideas please thanks again dave

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    1. Dave, if you've got a good source for the Bernzomatic Ultra Blue canisters, hang on to them. They aren't made any more that I'm aware of.

      I"m not sure what the nylon wadding is that you're referring to. I have a couple of the Bernzomatic canisters, but I don't recall any nylon wadding. Did you cut open the canister?

      HJ

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  8. Hi Jim, I brought four that was left on the shelf, when I googled them got photos and inside there is a nylon mesh, I thought there was something inside, I could not hear the propane inside. Have seen Primus Winter gas 230g has a Vapour Mesh same idea I thing? Any way it is a life saver when it is -20c lot fast to get snow melted and thanks to you remember to keep it standing up no need to place on it side or inverted great info thanks

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    1. Hi, Dave,

      That's interesting that there's some kind of mesh inside. I'm a bit skeptical about such things. I think the propane content more than anything else is going to make the difference.

      HJ

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  9. On the Kovea, is the output of the adapter is adjustable with the little screw on the side? How about the G-Works, can the center pin turn for that purpose or is the notch only there for the assembly?

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    1. Daijobu,

      Are you by any chance from Japan? Your screen name sounds like "good job" in Japanese.

      The G-Works adapter is not adjustable.

      HJ

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  10. Hi Jim,

    I have put the link of your review on this forum https://www.mountainproject.com/v/running-msr-reactor-on-straight-propane/112408605#a_112473845
    you can see there is a fellow that tried 100% straight propane (in fact 90%) on a Reactor stove,
    but I was not aware of the regulation valve....(MSR should think of making a 100% propane working Reactor stove though...)

    If you were to go for instance in winter on Everest at 26000 ft (could you say, that 90% propane can go down to -60F ? (just thinking....http://winterclimb.com/articles/item/111-mount-everest-first-winter-ascent-1980) and considering the 20 Fahrenheit degrees (10 Celsius degrees) above the vaporization point ?

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    1. Probably, yes, a stove can handle -60 F running on 100% propane. Of course at those temperatures other things can happen like seals becoming hard and brittle and the like. Generally, you should be fine, but if I were planning to venture out in such conditions, I would want to test my stove if at all possible in very cold conditions beforehand.

      As for running a Reactor on propane, I don't know that it's dangerous or going to harm a stove, but I don't know that it's safe either. I'm being very conservative here since I really don't know that it's safe for the person or safe for the stove.

      In cold weather, the vapor pressure of propane should not be so high that it would damage a stove. Again, I'm just being very conservative here.

      HJ

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  11. here cold vs altitude chart
    http://images.google.fr/imgres?imgurl=http://zenstoves.net/Canister/AltitudeVsTempMixedGas.png&imgrefurl=http://zenstoves.net/Canister.htm&h=293&w=692&tbnid=PbFvDGYRUo9nIM:&vet=1&tbnh=90&tbnw=213&docid=YqqARDUikRpH1M&client=firefox-b&usg=__vpBpfnl6iHqO4xs7xdKzttMW1dI=&sa=X&ved=0ahUKEwj78L3IvfbRAhXEnBoKHWQTDbEQ9QEIKTAC

    ReplyDelete
    Replies
    1. I updated my comments above about temperature and altitude restrictions.

      HJ

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  12. I 've got the Primus Himalaya (old model dated 2002) looking like this one :
    http://scher.narod.ru/Stove/Review/primus_EFS.htm
    can I try the G Works adapter with it ?
    Will it work safe ?

    thanks

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    1. Hi, Dan,

      I haven't tried the adapter with that stove, but it *should* be safe provided that you start with the stove on low and turn it up slowly. You don't want to turn it up too high.

      HJ

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  13. Jim - Thanks for the warning about vapor pressure and regulator valves. If I'm reading the charts correctly, the vapor pressure of 100% propane at 32°F is about the same as a 30/70% propane/n-butane mix at 75°F (see e.g. http://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html). So in theory it should be okay to use a propane canister with a backpacking stove in cold conditions (below freezing). Do you agree with that logic?

    BTW propane canisters aren't that much heavier than standard backpacking gas canisters. A 16oz propane canister weighs 780g when full, about the same as two 8 oz backpacking gas canisters.

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    1. Martin,

      I follow your logic. I haven't specifically checked the numbers, but in cold weather, I don't think having excessively high pressure is a concern at all. I'd be much more concerned above, say 70 F/20 C. Particularly below freezing, there should be no problem.

      Regarding weight. I have a couple of Coleman brand 465 g canisters of 100% propane in front of me. They weigh about 850 g each. The weights vary, but the lowest I've seen for a full 100% propane canister is about 840 g. By contrast, a 450 g Jetboil brand backpacking type canister weighs 660 g. That's a minimum difference of about 80 g (roughly 3 oz) for comparably sized canisters. Some Coleman 100% propane canisters weigh 870 g -- about 110g more than a comparable backpacking canister. That's about a quarter pound difference.

      HJ

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  14. I got the Kovea Spider and Kovea LPG Adapter (heavy!) and noticed that it sputtered quite a bit, even turned down low. I found it ran more smoothly in liquid feed mode (on a full green propane cylinder). However, on my most recent overnight trip (4500', 35*F), the setup didn't seem to work well heating water for breakfast. I began with the valve barely open, but found that the flame seemed to slowly fade, as if the valve was shutting. I had to keep turning it up. Keep in mind I was balancing that with not turning it up above 30% or patches of the flame would begin to sputter out, I assume from the higher pressure.

    Any tips or suggestions?

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    Replies
    1. I think I've had something similar on several stoves including the Spider. My theory is that as the pre-heat tube on the stove heats up the fuel in that section it rapidly expands and creates a back pressure when running in liquid feed mode. Exactly how each stove runs in this setup seems highly variable probably in part due to the variations in how much of the pre-heat tube goes over the flame. I think that ones with more pre-heat are more stable (small adjustments to fuel valve make little difference), whereas the Kovea Spider with a small amount of pre-heat is more finicky. That's my theory anyways.

      Delete
    2. Very strange, Scott.

      Sputtering is often caused by fuel that isn't fully vaporized. Have you tried it since then with regular backpacking fuel? The stove shouldn't fade on you in 35 F weather running on 100% propane.

      How full was the propane canister on your last outing, the one where it seemed to fade? Recall that the HD5 standard for propane (which is generally what you'll get in the US) allows for 5% "other" to be in bottles sold as propane. If you were toward the end of the bottle, then that last 5% may well have been butane in which case, you would definitely get some serious "canister fade."

      HJ

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  15. On the topic of alternative fuel source I've been experimenting with filling a butane canister with white gas then topping it off with about 10% propane. After warming up the stove I flip the canister and run the white gas with the propane staying at the top to provide pressure. So far it runs fine, but I still need to measure canister pressure and see how it runs in cold weather. My goal is to come up with a solution that runs well in very cold environments using a light weight canister and with lower pressure that straight propane.

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    1. Fascinating. What stove are you running that with?

      HJ

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    2. I've tried out the fuel on several stoves. The Primus Omnifuel and Lixada Portable Multi Fuel both burned well after the pre-heating phase. That's no surprise as they are both made for canister or liquid fuel. Canister only stoves seemed to only work if they had a large preheat tube over the flame. Primus ETA spider and Optimus Vega did fine once pre-heated although not surprisingly they only had one setting, high. Kovea Spider and Fire Maple 118 seemed to never get the pre-heat hot enough and continued to put out a yellow flame. I was able to verify with a pressure gauge that the pressure in the canister is much lower than with high propane mixtures. Actually lower than regular butane. The fuel was about 45 degrees. I have it in the deep freeze now and will test it again at about -10 F. I may want to go with a higher propane ratio. So far the mixture seems to have some potential, but time will tell if it's actually practical. Pre-heat seems to be a little longer/trickier and getting the white gas into the empty canister is a small process to itself. Still it has been some fun experimenting.

      Delete
    3. Be careful of that Lixada Portable Multi Fuel. It's a cheap knock off of the Kovea Booster+1. It is not the authentic Kovea product. It may be fine, but I really don't know.

      That's interesting what you're doing. Basically, you're developing a white gas stove that is self-pressurizing, a pumpless white gas stove. A fascinating idea.

      It makes sense that the stoves designed for liquid fuels are going to do better. You need a certain level of thermal transfer from the heat of the flame to the liquid fuel flowing through the fuel line. A white gas stove is going to be designed that way. A kerosene stove even more so. On the other hand, canister gas doesn't require as much heat in order to vaporize the fuel, so they deliberately would design them with less thermal feedback in mind.

      HJ

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  16. I have this adapter and the Kovea one. I like the weight of the G-works, but it doesn't work with 16 oz propane bottles that are made to be refilled. The Kovea works on both the disposable and refillable 16 oz bottles. The threads on the refillable bottles seem to be slightly thicker and won't allow the G-works to screw on all the way.

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    Replies
    1. Interesting. I haven't tried the refillable propane bottles. Good to know.

      HJ

      Delete
  17. Hi Jim

    when running a backpacking stove upright with Isobutane, you get a freezing canister since the vaporisation cools the canister, it's ok down to 10 F, a cozy is useless in this case.

    when running it inverted, you can go down to -12F without the problem of a freezing canister linked to vaporisation, however -12F being cold, the canister can start to freeze but a cozy would help here, right ?

    If applying this to Propane, one can suppose to be able to vaporise it down to -43F
    but in liquid mode, one could go even lower ? what would be the limit at sea level ?
    (even altitude could help to outclimb the cold)

    A one inch close celled foam cozy for the canister could be the answer to help running the propane in liquid mode without worries ?

    would the preheated tube come into play in liquid mode ?

    thank you

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    1. Dan, be careful of using rigid numbers like the 10 F and -12 F you mention above. It very much matters what fuel blend you are using, the temperature of the fuel more so than the air temperature, what elevation you are at, and whether or not you have a regulator valve or are running in inverted mode. I don't think you can have numbers quite as hard as you list (at least that's how I'm interpreting what you're saying).

      In upright mode, generally you are correct about a cozy. A cozy is typically of little help since the canister cools from within. However, if one were to put a hand warmer or other heat source inside, then a cozy could be of value. That said, it's still typically worthwhile to insulate the canister from the ground.

      With inverted operation, the canister will still cool from within, but to a far lesser degree. Here, a cozy might have actual value, particularly if one were to start (as I recommend) with a warmed canister. However, liquid water would be of even greater value than a cozy in most circumstances. Liquid water will always be above 32 F which should allow any propane-isobutane mix to work well, particularly in inverted mode.

      You could not go lower than the boiling point of propane (-44F) in liquid feed mode. You still need enough pressure in the cylinder to push the liquified propane through the fuel line and through the burner. Generally, you want to be about 20 Fahrenheit degrees above the boiling point of a fuel for good pressure although you could probably go a little bit colder in inverted mode/liquid feed mode.

      Would a pre-heat mechanism come into play in liquid feed? Uh, yes. Indeed, if you try a liquid feed without a pre-heat mechanism of some sort, you're going to have a fiery failure on your hands. A pre-heat mechanism doesn't just come into play, it is required. Let me repeat that for emphasis: You must have some sort of pre heat mechanism in place in order to use liquid feed in any fashion.

      A pre-heat mechanism has to supply enough heat to fully vaporize whatever fuel you are using. If liquid fuel actually exits into the burner, you'll have a fireball erupt like a volcano out of your stove. You must supply enough heat to the fuel to fully vaporize it before it hits the burner.

      HJ

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  18. ok Jim !

    one more thing, in propane mode, do you think altitude can help in inverted mode at -40F ?
    or does the stove work the same regardless of the altitude when inverted ?

    Next,the problem you are facing at -40F is how to keep liquid water for warming the canister...?
    (if you can see a pot of boiling water thrown in the air that can freeze before it actually hits the ground....?)

    as a result a cozy with a toe warmer inside is not that bad ?

    if this fails, you can still urinate on the canister ....that works !

    or use a candle, at -40F a candle is not as dangerous for a canister pressure as it is at +90F..

    then, if gas fails at - 44F, what others fuel can work down below ?
    what is the absolute limit and how to deal with it ?
    I think of the cross of Antartic in winter
    http://www.livescience.com/37609-expedition-abandons-antarctic-winter-crossing.html

    cheers

    Dan

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    1. Dan, yes, the higher in terms of elevation that one is, the better a gas stove will work at a given temperature. At -40F at sea level, you are pushing the limits. You would want to have the capability to keep the fuel much warmer than that, say at least -20F, in order to have good pressure -- if you have true, laboratory grade propane. But of course you won't have lab grade propane; you'll have commercial grade propane which is only about 90% actual propane. So, don't count on -40F or -44F or any other number down that low. You have to be very conservative here until experience teaches you otherwise.

      At such cold temperatures, water is no longer a good mechanism for warming the canister. A candle would be fine, but I'm not sure if a candle will be enough. You'll probably want some kind of a Moulder Strip that channels heat back to the gas cylinder. You have to be exceedingly careful when mechanically channeling heat to the fuel, but that's probably what you'd have to do at such an extreme temperature.

      The other option is some type of white gasoline stove. Optimus used to make Arctic Fuel which was a highly refined white gasoline before the company was sold. I don't know if they're still making it.

      HJ

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  19. Hello Jim

    so would you be ready to do a stove bomb in -20F weather ?
    the canister would have yet to be too warm, would it ?

    http://gearthirty.blogspot.fr/2012/03/alpine-bomb-for-msr-reactor.html
    http://www.ademiller.com/blogs/climbing/2005/12/gear-the-alpine-bomb.html

    PS : Have you ever heard of the PALS system ?, I think a good stove + a good knowledge + the right stuff can save your life no matter what...
    when you get your priorities straight.

    cheers

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    Replies
    1. Dan, yes, in temperatures that low, I would consider an "Alpine Bomb" type of set up. I think water will be too difficult to work with and keep warm. This bomb type set up is what I meant when I earlier said that one needs to channel heat from the burner back to the fuel.

      Caveats:
      1. Use only in cold weather.
      2. Constantly check the canister by touching it with bare skin. If the canister is so hot to the touch that you can't rest your hand on it comfortably, then it's TOO HOT. You have to immediately take steps to reduce the amount off heat being delivered to the canister.

      I have not heard of the PALS system before today that I can recall.

      HJ

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  20. This comment has been removed by the author.

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  21. one more thing please

    how can this canister C300 Xtreme gas cartridge be reliable down to -16F, being filled with 40 percent propane only ? (as 90 percent propane is good to -20F...only)
    http://www.coleman.eu/benelux/p-26637-c300-xtreme-gas-cartridge.aspx
    and how can this canister withstand the pressure, it looks like a common canister....

    thank you

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    Replies
    1. Dan,

      Well, this is a bit tricky. The HD5 standard for propane calls for a minimum of 90% propane, no more than 5% propylene, and the remainder can be any petroleum gas (methane, ethane, butane, etc.). The bottom line here is that you can't know exactly what is in the mix. In all probability, it will behave a lot like propane in terms of vaporization characteristics and heat produced, BUT it's worth it to be conservative which is why I'm recommending something on the order of -20F as a lower limit. Keep in mind that in upright use, the propane and higher vapor pressure gasses (e.g. methane) will burn off at a faster rate leaving the lower vapor pressure gasses (e.g. butane) in higher concentrations toward the end of the life of the cylinder. In other words, the last, say, 10% of your fuel will not perform nearly as well as the first 10%. One has to be prepared for this "canister fade" as it is sometimes called.

      Again though remember that it is the temperature of the fuel not the air temperature that matters. If you can channel enough heat from the burner back to the cylinder of gas, then you can operate at as low a temperature as you like. Of course you need to start with the cylinder warm enough in order to start the cycle.

      Now, all that said, do I believe that there will be good pressure in a 60/40 mix down to -27C (-16.5 F)? Well, it depends on how pure the propane they use is and what the other components are in the mix. In this case, at least 60% is n-butane which vaporizes at -0.5 C (31 F). So, no, I don't think this C300 canister will work well consistently at -27 C/-16.5 F. Maybe if you start with a fresh canister, keep it warm, and use it in inverted mode -- but not in standard upright mode. I don't believe it, not throughout the entire life of the canister.

      HJ

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  22. Great read Jim big thanks at the moment using up my 50/50 still -26c no idea in F works great even though I have the ultra blue canister's 100 propane like to finish the mixes first still have three months yet again great information keep it coming Dave Labrador,Canada

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    Replies
    1. Hi, Dave,

      Yeah, those Ultra Blue canisters are great, aren't they? I wish they still made them.

      Thanks for your remarks,

      HJ

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