Forum Index » General Lightweight Backpacking Discussion » Evaluating what stoves to use for what lengths of trips


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Harald Hope
(hhope)

Locale: East Bay
testing on narrow pot on 08/03/2013 13:12:53 MDT Print View

Paul, also, yes, there should be tests on wide pots, because those always get better efficiencies. Because I prefer narrow pots, I have focused my testing on 10-11cm wide pots, which are 600 to 900 ml basically. I have a 1.3 L evernew though but I have a hard time motivating to set up the tests/screens for that because I never use it, but I know the efficiencies for alcohol will be at least 1 gm per 2 cup boils improved.

So while you will need more fuel for a 4cup boil, you should get better efficiency, but I believe that should apply to all stove types.

Now that I have the basic rows setup, it's not going to be too hard to add variations to them, ie, more rows per night. I'm tempted to pick up an msr pocket rocket or something like it too for testing, but the notion of trying to make a screen setup for that type of system does not at all thrill me, seems kind of convoluted to me. That's why I ordered a remote canister, that lets me test with real screens and optimal efficiency, just like with alcohol. There is about a 70gm weight penalty over top mounts there though, but to me that's not a big deal, I'll clearly never be bringing canister setups for the weight anyway.

Ken, yes, that's not terrible, but he's neglecting the stove screen in his tests for alcohol and remote canister, and the stove he used isn't I believe all that great, wasn't bpl selling the ion stove back then?

I think one major error people make with alcohol is neglecting the fitting / ventilation of their screens to the pot, ie, the notion you take a fancy feast can, then get some aluminum foil and punch some random holes in it with a random screen height isn't right, it works, but it's not how you get efficient setups in general.

Steve, the simmering ability of an ion or penny or probably most other types where the simmer ring has been developed as part of the system is beyond belief stunning, I literally could not believe it when I first saw the time/weight efficiencies. I will test this one day for dinner, but I believe you can cook 1/2 cup of uncooked brown rice using roughly 12 grams of alcohol, it should be close to that because you need roughly 6 to boil the 1 cup of water and 6 to simmer it 20 or so minutes, not sure on the smaller amount of water/fuel simmer time, I only tested 2 cups. In fact, I would suspect that even if you like canister stoves, you'd be well advised to bring a good alcohol stove with you for the simmering part of the meal.

I agree with your alcohol pluses, though personally I'm just not interested in getting fuel where I have to buy it by packages like esbit, particularly if it smells and leaves films of gunk, so I never really thought about using it, though I can see the convenience of it for sure. I would have listed the fiddle factor of a stove needing priming and little pieces, like the Penny, as a significant negative, but that's why I rediscovered the ion type, I was trying to get rid of the two main disadvantages of my alcohol stoves, fiddle to light etc, and setup, and the lower efficiencies I was getting. The ion type system is so absurdly easy to use and setup and light and refill and simmer with that in my opinion all those negatives were fixed, at which point what's left is something basically as easy to use and setup as a canister, easy to store, light, and truly simple. Sgt rock did a fantastic job when he did this research, and I do not understand why it's not a standard setup, no cone required, everything fits in the pot, super clean and simple. I'm sold, for solo use.

Edited by hhope on 08/03/2013 13:33:34 MDT.

Paul McLaughlin
(paul) - MLife
Re: it's all linear on 08/03/2013 14:12:20 MDT Print View

While the fuel usage may be linear the container weight as a percentage is not, with canister gas getting more efficient in that regard as the quantity of fuel gets larger (220gm canister, then 450 gm canister). So a canister stove gains by that if the usage per day goes up, while an alcohol setup doesn't since the container weight is so low to begin with.

Re white gas for very long trips - I have done some analysis and testing of the stoves I own with the intent of finding the lightest setup for spring snowcamping trips of 8 or 9 days. What I came up with was that for my usage, canister and white gas would be about the same - within a few grams at both the start and the end of the trip. The key is being able to carry white gas in a plastic bottle, so that as the trip gets longer the total fuel/container weight per BTU drops, while with canisters the ratio cannot get better than what you get with a 450gm canister. Of course, if I had one of Roger Caffin's nice remote canister stoves that would take the lead, but it would only be by a couple ounces, and at some point the white gas stove (Simmerlite)might still catch up.

Just as a data point, what I came up with for snow camping fuel usage, by tracking what I use on trips, is that if I have to melt snow it takes me twice as much gas as if I don't. My average WG usage per day for two people melting at both dinner and breakfast is 124 gms. I also found that as a simulation of that, bringing 12 cups of 50 deg water to a boil is pretty equal to a meal for two.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: it's all linear on 08/03/2013 15:45:50 MDT Print View

> at some point the white gas stove (Simmerlite) might still catch up.
Unlikely.
White gas stoves are almost always heavier than even remote canister stoves these days, and in general I find one uses about 50% more white gas than propane/butane. Reasons are that priming a white gas stove takes a lot more fuel, and there is always the temptation to leave a white gas stove running between uses to avoid having to prime it again. Oh yes - the wqhite gas tank and pump has considerable weight too.

Oh well, I dare say one could find a special case at the transition between canisters where a carefully measured amount of white gas works out close to equal. Contrived.

Dinosaur technology.

Cheers

Harald Hope
(hhope)

Locale: East Bay
just tested white gas on 08/03/2013 16:34:01 MDT Print View

I did one test, just to see, for old time's sake, 1.3 L evernew, whisperlite.

I don't know if the term 'dinosaur' is applicable, I took some many year old fuel, attached everything, fired it up, and water boiled in 3.25 minutes. I hadn't used this stove in probably 3 years beyond one test start a few years ago. Because this stove allows room for user error, obvious from reading the instances where people manage to blow these up, which is something I have no idea how to do, you have to really overpump it to stress it, but if you let in that type of room for user error, you will get user error, along with, like any mechanical device, including canister stoves, mechanical errors and failures, another area alcohol does very well, no moving parts. That will have to change in the future, we need an alcohol stove with a true on/off switch for fire danger issues.

Consumption was not good for this test, 70F start, 14.5 gm boiled 2 cups. For all I know I have the wrong nozzle jet adapter on it, I think this is the international version, not sure, I have both. I also probably used a touch too much priming quantity.

But the power is excellent, it was breezy outside for this test and I could see no loss of flame power at all. The old bpl test showed simmerlight at 11gm, but I did not spend much time on the test, and it was windy. I believe with practice you can optimize the fuel consumption by priming less, if I remember right, not sure.

However, white gas has the same advantage as alcohol, you can take what you need, exactly, plus it's very fast, and you are not bound to finitely sized heavy canisters. Simmers poorly in whisperlight, but not as badly as in xgk.

I'd say the white gas advantages are the same as always, takes basically any fuel, you can determine how much to bring, etc, incredibly strong flame, no cold issues I am aware of, virtually wind proof. But it's heavy, and in the context of this thread, very inefficient. Efficiency improves however the longer you burn it since you only prime it once. The start up wastes a fair amount of fuel.

I believe a better area to test whisperlight against canister stoves is large quantity boils, 4 to 8 cups, particularly snow etc.

M B
(livingontheroad) - M
stove on 08/03/2013 16:38:15 MDT Print View

I agree, many alcohol stoves are too fiddly.

If it needs to be primed, it falls into that category to me.

Its my opinion that alcohol stoves are a lot like fishing lures.

They are made not to catch fish, but to catch fisherman.

Its not that complicated.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Dinosaur technology? on 08/03/2013 17:06:37 MDT Print View

"Dinosaur technology"

I'm another who doesn't quite agree with that characterization.

For one thing, once you have really learned how to do it, the whole priming/flare up problem becomes tiny. I got to the point where I knew exactly how many pump strokes to do and how much to turn the valve and for how many seconds, and I got the priming fuel usage down to a minimum. That was on a high mountain ascent where we were completely tent-bound for all snow melting and cooking for about eleven days.

Another factor that hasn't really been discussed too much is fuel cost. If you are doing lots of snow melting and cooking for multiple mouths, you will go through a lot of fuel. At least for me, white gasoline (Coleman fuel) is cheaper than the alternatives for a given amount of heat.

Now, of course you can beat the cost by burning wood or something. However, for any high mountain trip in winter, I will always grab one of my white gas stoves.

--B.G.--

Harald Hope
(hhope)

Locale: East Bay
agree on 08/03/2013 17:45:03 MDT Print View

Bob, agree, you've done a lot of winter backpacking from what I've read from you here, and what you say makes me think the real test here would be: stoves taken into snow, outside temp cold, cold ground, melting snow as main task. That would expose the shortcomings of various canister setups, for example. Whisperlight has no shortcomings in terms of function that I am aware of, just the weight, that's why I always used those stoves in the past. In a sense, if MSR or someone else had focused more on efficiency of boils, they should have gotten the 2 cup boils down to 8gm fairly easily I believe, gasoline holds a lot of energy, and I'd say the whisperlight test I just did got no better than about 30% efficiency, maybe 25%.

The whisperlight isn't going to compete with any of the methods so far discussed in normal weather backpacking, but then again, nobody is generally claiming that you can melt snow well with alcohol either, so it may just be different tools there for different situations.

A table of that type of cold weather snow melting data would be interesting, but something tells me that when you're out in the cold trying to get some snow melted, weighing things carefully is probably not super high on the list of priorities, heh heh. That's a place where kitchen or workshop testing just does not cut it, you have to do it in the real weather with real snow etc. I'll leave that alone because that's something best done if you live in a very cold climate and can do real outside testing in snow/cold.

[added]However, given that many people do use whisperlights, I will add the numbers to my main table so they can see the differences for themselves, most people here know this already, but I know I never gave it a thought in the past.

Edited by hhope on 08/03/2013 17:47:56 MDT.

Paul Magnanti
(PaulMags) - MLife

Locale: People's Republic of Boulder
Number crunching on 08/03/2013 18:00:17 MDT Print View

These numbers are great!

Sure the numbers posted by many people will pan out in the real world vs a back yard test or an Excel spreadsheet, :D

Edited by PaulMags on 08/03/2013 18:02:14 MDT.

Harald Hope
(hhope)

Locale: East Bay
thanks bob on 08/03/2013 18:09:07 MDT Print View

bob reminds me that you do have to practice a touch with white gas stoves, test 2 yielded 12 gm boil, with about 1 minute plus continuation of boil after shutoff as the gas in the tubes continued to burn, so you could get even better efficiency by turning off the stove right before it fully boils. I also kept the flow knob set quite close to closed, but open enough for full burn, about 1 turn or so.

So I'll call it a 12 gm boil for now, I was more careful priming it too. That accords well with the old bpl white gas numbers of 11 gm boil too.

I'll add this to the table, in all these cases, I want to be fair to each stove type, and present a decent middle case.

Edited by hhope on 08/03/2013 18:09:53 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: agree on 08/03/2013 18:21:33 MDT Print View

"gasoline holds a lot of energy"

Yes, and the negative people around here will claim that they are dangerous as a result. I hear that, but that is purely a user-training issue. Some of us got our feet wet with white gas stoves 35 years ago, so we have long since gotten past the beginner stage.

I would have to take an inventory now, but at one point in time I had about six MSR stoves, mostly model GK, XGK, or XGK-II. I've never owned a Whisperlight, although most of my friends have them. I think I have one new Simmerlight.

If we were going out to do a week-long ski camping trip, we would not consider taking stoves other than white gas type.

When we did one high altitude climb, the 14-member expedition was divided up into tent/cooking teams of two or three. Every one of the teams was using a white gas stove. Most, but not all, of the other expeditions were using white gas stoves as well.

--B.G.--

Harald Hope
(hhope)

Locale: East Bay
thanks for input on 08/03/2013 18:39:51 MDT Print View

Bob, do you have a rough feel for the efficiency re snow melting of the msr type stove?

ie, how many ounces fuel to create x cups water?

I'm working up the whisperlight chart now, and it's not nearly as bad as I thought. By the way, the old 32 oz aluminum fuel bottles weigh LESS than the new 20oz steel ones. Some sigg bottles fit, but you have to be certain it's the same threading. I am using 7oz aluminum, 20oz steel msr, and 32 oz aluminum msr for the fuel bottle weights. However, the 20oz bottle takes you to 17 nights.

If I spent the same time creating a custom fit and air gapped wind screen for the whisperlight I did for the ion, I have little doubt that I can hit 10gm efficiency with white gas fuel.

ie, a bit better than alcohol, but massively hotter.

Early results are in, the msr whisperlight is no more a 'dinosaur' than a remote canister stove, it's quite similar re starting weights for shorter trips, and for very long trips, or trips where you boil a lot of water (54 2 cup boil equivalent). When I add in the 60-100 extra grams or so for a remote canister stove, and subtract the heavier original msr windscreen, the weights are basically the same for those two systems if you start with a 220 gm canister, and not all that far off with a 100 gm. It's too bad msr is kind of conservative with this stuff, if they did a ti ul version of their stoves with aluminum fuel bottles, they are really not all that far off.

Edited by hhope on 08/03/2013 19:28:10 MDT.

Harald Hope
(hhope)

Locale: East Bay
don't throw out the dinosaurs on 08/03/2013 23:08:06 MDT Print View

I've added a second table (under the first one, day 1-14) for larger consumption numbers, while still using 4 cups per day, I break it to 14/16/18/20/22/24/26/28 days, which is the capacity of basically the 32 oz MSR white gas bottle or the 450gm canister.

Roger should probably re-evaluate his views on white gas, the numbers do not support them particularly well for large volume usage, if you are doing snow camping, and use a remote canister stove, between 146 and 200gm, there is in many cases virtually no difference in weight between the carrying weight of a white gas and canister stove, sad but true, that's because the canisters are just so heavy that they get rid of any actual edge you might gain. A 32 oz aluminum fuel bottle weighs 113 grams, if the numbers I got online are right, a 450gm canister container weighs about 250 grams.

Also, of course, you can use plastic bottles to carry more white gas fuel, and this is of course why Bob noted everyone at the alpine camp used white gas stoves. Plus white gas doesn't freeze or have other cold issues particularly, it's kind of a no brainer I'd say if you have the white gas setup already.

It's interesting however seeing the actual numbers as they roll off my calculator. Since the most likely time you'd be using very large cartridges or white gas is for either snow melting or very large volume water boiling/cooking, as you can see, it's basically a toss up which you bring, it could literally depend on if you have a partially empty canister or not to fill out the days. Seems like a big pain to me, liquid fuel is so much more convenient, but each to their own.

Here's what it would look like on a 10 day trip with 8 cup a day boils. IS is ion stove, PS is penny stove, 45C is a 450 gm canister top mount setup, W32 is whisperlight white gas with 32 oz bottle.

day/night 1 7 8 9 10
9 - IS 551 239 191 143 95
9 - PS 713 297 233 169 105
9 - 45C 810 602 570 538 506
9 - W32 944 632 584 536 488

slightly more starting weight for white gas, return weight is about the same. Hardly worth changing anything in your setup I'd say. And that's not a remote canister stove, if you add those 80 grams, there's essentially no difference at all. Live and learn.

Note also that if you do longer boils, the actual fuel required in white gas is less because you lose less to priming, so these numbers would actually be a bit better for W32 for 4 cup boils or snow melting, ie, you'd need less than the fuel amount per day I estimated, which might actually bring the numbers between a 450 gm canister and white gas basically to being equal, or even better for white gas. Keep your whisperlights, your xgk's, etc, these are good stoves and the canister stuff doesn't offer much improvement that I can see for more heavy duty use.

Edited by hhope on 08/03/2013 23:14:51 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: thanks for input on 08/03/2013 23:31:01 MDT Print View

"Bob, do you have a rough feel for the efficiency re snow melting of the msr type stove?
ie, how many ounces fuel to create x cups water? "

I have no current numbers.

This will sound strange, but I used to estimate the amount of white gas to carry on a trip by time. One liter of white gas made a minimum of four hours of full flame on my XGK. It would be longer for less than full flame. As was mentioned earlier, when you do a snow camping trip and have to melt snow for drinking water, you double the amount of white gas to carry as compared to no snow melting.

--B.G.--

Harald Hope
(hhope)

Locale: East Bay
canisters lose on 08/03/2013 23:52:02 MDT Print View

I just retested whisperlite white gas on a 4 cup boil to more closely emulate what you'd use it for, and the fuel consumed was only 18.2 grams, as opposed to the 24 I'd been using as my first guess, and the 11x2 that the bpl table would have suggested. And I also turned it off too late so that included an about 2 minute boil after the full boil was hit as the fuel in the lines burned. 6 minutes to boil plus 2 minutes of boiling. In other words, the gram efficiency of the white gas is the same as canister gas, and that's not using an optimized wind / heat screen.

So I'd say you could do a 4cup, 70F start temp, boil using about 16 grams white gas, or so. But I'll call it 18 for now.

That's an improvement of 25% over the two cup boil. This makes the canister basically lose once the starting fuel weights are large enough, particularly with the added weight of a remote canister stove, which weighs between 145 and 200 grams from what I have seen for the kinds you'd use in snow camping, ie, where you can turn the canister upside down.

Bob, it doesn't sound strange, that's how I always used mine too, for cooking fully meals, no cozy, I needed about 40 minutes a day burn, for 9 days that was about 360 minutes. or 6 hours, or a 32 oz bottle.

The more I look at canister stoves, the worse they look, but that's not really a surprise to me, liquid is just a better way to carry energy than gas, that's why we generally use it in our cars, that wasn't an accident, the weight required to carry compressed gases is significant.

I'm going to update the chart, because unless you are boiling more than 2 cups per meal, there's not a lot of reason to bring a white gas stove. I knew the test data I'd found online was bad for stoves in general, but this type of example shows just how bad.

If it's a simple doubling of quantity, that would mean that melting it takes the same rough energy as boiling it, which sounds about right to me.

Edited by hhope on 08/04/2013 00:49:46 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: canisters lose on 08/04/2013 00:26:59 MDT Print View

Harald, now you have to sell this whole concept to Roger Caffin. Good luck.

--B.G.--

Harald Hope
(hhope)

Locale: East Bay
he's gotten sloppy on 08/04/2013 01:00:15 MDT Print View

maybe the white gas stoves are too complicated for him to operate, no idea, but I approached this as Richard Feynman suggests in 'The pleasure of Finding things out", ie, do not assume you know, allow doubt, reject certainty, do not accept bad test results, do not attempt to prove things to confirm your existing bias. Allow the data to guide your inquiry. Having opinions is fine as long as you don't forget that they are an opinion, not a fact. I believe engineers in general are more prone to opinions than scientists, it's easier to just do stuff in engineering then see if it works, I can see the difference. Feynman also reminds us to never listen to 'experts', that's a direct quote from him, and this is why you don't, experts get lazy and stop testing, because they are experts. I'm not an expert so I tested this stuff, and the results are pretty clear.

I only did the whisperlight for old times sake, but the fact is, if you compare a reversible remote canister setup with a whisperlight, particularly where you will use it a long time per day, the whisperlight is equal at least, maybe superior, but definitely almost the same weight, except you are not bound to silly fuel canisters that you cannot fill out of other fuel containers, meaning you need that heavy metal shell for each and every gram of your gaseous fuel.

I did not expect the white gas to be even remotely in the ballpark of alcohol, and it's not, particularly if you use the pounds/mile metric for weight, ie, what you actually carry over the trip miles, beginning to end.

What surprised me here was just how good whisperlight is compared to gas, plus of course, this is liquid fuel and no worries about the cold etc. When you add remote canister, the small weight advantage of canister stoves vanishes for large boil/melt amounts, that's a fact, and you can discover this fact in about 3 test runs of your stove. And, as you noted, you do get a bit better efficiency with practice on the whisperlight type stove. For a 3 night/4 day trip to the snow melting and boiling 8 cups a day, the 15 night/16 day number I list should be close to the consumption.


day/night 1 14 16
15 – IS 455 143 95
15 – PS 560 169 105
15 – 45C 810 602 570
15 – WW32 848 536 488
15 – 4WW32 758 524 488


As you can see, the 4WW32 yields better start and end weight than the 450 gm canister setup, particularly since you'd be using a 100 gram heavier burner probably for the remote canister to melt snow in the snow. Dinosaur, lol, yeah, right, more like a bird that's very well evolved. Good designs are good designs. The svea 123 is I believe also still a good stove.

That's why it's fun to poke at these things now and then, I'd never done an actual efficiency/consumption test on my whisperlight, nor had I ever used alcohol stove type boil then turn off methods, so this is not bad at all. You do only get the really good white gas efficiency when you cook for more than one, or with snow melting from these initial tests however, I guess for 6 cups it would be a touch better still, probably I'd guess around 26 grams or so. Gas and alcohol should burn fairly consistently, ie, 1 gram fuel heats x gm water, as long as the stoves are made right. Certain alcohol stoves are prone to the 'warm then boil too fast and burn inefficiently then peter out' type performance, but the right design gets rid of that problem. Gas burners just turn the gas on and off, so I assume you can take their efficiency and just multiply or divide by 2 or whatever.

I'm actually impressed by the white gas, I was not expecting that, but it figures, some designs and ideas are just very good, and they don't really stop being good just because people want the next trinket to buy, even when it isn't even actually any better.

Edited by hhope on 08/04/2013 01:26:13 MDT.

Drew Jay
(drewjh) - F

Locale: Central Coast
Esbit on 08/04/2013 02:08:01 MDT Print View

Harold, you should include esbit as it bests any other system in terms of carry weight, trumps alcohol in boil times and efficiency, and very nearly matches canister stoves in efficiency. To use my two systems as an example:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=75650

The system weight is 42 grams (cone, esbit burner, foil ground shield, tyvek cup and ziplock.) There is no weight penalty for longer trips. It will boil two cups of cold tap water plus a dissolved ice cube using 9 grams of esbit. That's a conservative number, it has done better on occasion.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=76137

System weight is 38 grams (windscreen, esbit burner, foil ground shield, rubber band, ziplock.) It will also boil 2 cups cold tap water plus a dissolved ice cube using 9 grams of esbit.

These systems can also be used to simmer with a very simple and very light change or addition to the burner.

Edited by drewjh on 08/04/2013 02:11:29 MDT.

Harald Hope
(hhope)

Locale: East Bay
not enough info on 08/04/2013 12:44:21 MDT Print View

Re esbit, I still do not have enough information. What I need is real world consumption for 2x2 cups 70F water over days, ie, how many tabs used per day/2 cup boil, weight per tab, etc.

esbit strikes me as being a bit more awkward with varying water temps since you basically have to know how many tabs/parts of tabs to use for 70f, 60f, 50f, 40f water. With alcohol you just squirt in a little more for colder water, with gas you leave the burner on a little longer, as with white gas.

In other words, on a real multiday trip, how do you really do it? Ie, 1.5 tabs for 2 cups?


Steven Evans
(Steve_Evans) - MLife

Locale: Canada
Re: Coghlans "Esbit" Tabs -- Weight? on 01/25/2011 16:09:22 MST Reply Report Post Print View

I use the Coghlan's tablets religiously. Each round tablet weighs 6.5 grams. I get 2 cups of water to just boil on 2 tablets. A box of 24 costs me about $5.99 at the local "Canadian Tire".

I used to use Esbit (the 14 gram tablets) but they were more expensive, harder to get, and I didn't notice a performance difference. Hope that helps.

John S
(jshann) - F
Re: Coghlans "Esbit" Tabs -- Weight? on 01/25/2011 16:56:15 MST Reply Report Post Print View

Square esbit sold in US is about 14 grams per tablet. bpl solid fuel weights


Not all the data required, but if it's correct that 13-14 gm are required, that's not particularly different from SLX. I'll add esbit as soon as there's some agreement on realworld consumption for 70f 2 cup boils, has to be the same numbers as the other tests use. Personally I use 2.5 cups for morning and 2 or so for evening, though I don't boil the 2.5 completely before taking the tea water out. I've noted some people, particularly the canister users, have adapted to the shortcomings of their stoves / consumption by boiling less water.

The efficiency of gas stoves doesn't appear to be all that good to my eyes, ie, good alcohol stoves burn alcohol with about 55% efficiency, great ones, 60%, average ones, 50% or so. I haven't worked out the gas canister efficiencies, but I doubt it's better than that. I'd have to figure out the kjoules per gram for gas to really know. From what I read, the fuel in esbit is a touch more energy dense than ethanol, something like 13 vs 12 for ethanol and 9 for methanol, SLX is about 10.5. gas is about 20, I'm dumping the units, that's the proportions roughly. If the stoves had the same efficiencies, a good gas canister setup would require about 6 gm to boil 2 cups water, but it seems to take about 8, ie, the setup is not as efficient. Same goes for white gas, I believe it's a bit less efficient than gas from what I can see once you actually burn the stuff in the real world. Cars, by the way, with gasoline, are only about 30% efficient. Alcohol, and probably esbit, win these efficiency things because the stoves/screens can be highly optimized without requiring machine tools and a big shop. I'm sure you could likewise optimize the burner units/screens for white gas and canister gas.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: not enough info on 08/04/2013 13:26:23 MDT Print View

I take a completely different direction for Esbit usage.

Before I start my meal, I light one standard Esbit cube, boil the water, and then eat the food. If it is critical to have the water boil, then I light a second Esbit cube right over the black residue of the first one. When my water has boiled, and there is still a cube flaming away, I blow it out. That leaves some large fraction of a cube ready for the next boil, but that is OK.

Also, I've found that the partially burned fraction will relight very easily. When it was blown out, it is left with a furry/spikey texture over the surface, and this seems to make the relighting task much easier for my mini-BIC.

--B.G.--

peter vacco
(fluff@inreach.com) - M

Locale: no. california
whisperlite burn times. on 08/04/2013 13:34:59 MDT Print View

(for Harold) a long time ago.. in a world far away.. i had a job where it was possible to make endless cups of coffee (w/Kahloahh), and get paid while doing it. so, being a good bpl'r, to that end i optimized my stove.
by installing the K jet in my whisperlite inter and removing one set of burner rings, i was able to consistently get 17 minutes out of a fluid oz of fuel.
output is diminished to some extent.

cheers,
v.