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Paul McLaughlin
(paul) - MLife
a few numbers esbit and white gas on 08/04/2013 14:38:06 MDT Print View

My experience with Esbit is limited but for what it's worth: when I used it on a Sierra summer trip, I used one Esbit brand tab each meal, basic Esbit folding stove (all I had ever seen at the time, 10+ years ago), homemade foil windscreen, 3/4 liter fairly wide stainless pot. The one tab boiled the 2 cups water and then simmered a few minutes while I stirred, every time, in roughly 50-60 degree air temperatures. No data on the water temperatures but straight out of a Sierra lake I expect 50-60 degrees at most.

White gas numbers: I have tracked my fuel usage on several spring snow camping trips. I keep track of total fuel usage for the trip, and the number of nights I find water and thus do not have to melt.
Averages, in ounces by weight:
if melting, for one person - 3
if not melting, for one person - 1.5
if melting, for two persons - 4.5
If not melting, for two - 2.25

The obvious points - if I have to melt I use double the fuel, and two persons use 1.5 times the fuel of one. However, my ski trip partner eats less than I do so he needs less water to reconstitute, partly explaining why the fuel usage for two is not double that for one. I realize priming fuel use plays a part here, but I believe a very small part, simply because my method is to light the stove once for each meal and once only. Also, when melting, I would melt some snow for cold water as well as for the meal, so one should not assume that melting enough snow for a liter and then bringing that to a boil would use double the fuel of just bringing a liter to a boil.

I have also tested my stoves at home to compare them. To do this I started with 12 cups of 50 degree water and brought it to a measured 210 degrees. Fule usage measured included priming. I have both a whisperlite and a simmerlite, and they came out the same, at 43 grams of fuel to do the job. Coincidentally, this is very close to my number for daily usage for one meal if I am solo and melting snow, so it's a reasonable simulation in that is is a single burn of about the same usage, thus having the same ratio of priming to running. I also have a remote canister stove, but it is a Bulin B5, which is notorious for fuel line problems, and when I ran the same 12 cup test, with canister inverted, I noticed it did not run as well as it had in previous testing with the canister upright. So I don't consider that an accurate test, and until I get another remote canister stove I can't compare accurately. I did run this test with my canister top stove - a Coleman F1 Ultralight (since deceased) and it used 34 grams of fuel to do the job. BPL testing in the past has shown that remote canister stoves seem to be less efficient than top-mounts - though why this is the case is not clear, and it may be differences in burner design. (Roger, can you please compare fuel usage of your remote canister stove to the the top-mount stove whose burner head you are using?) At any rate, even if we assume that a remote stove will be as efficient as the Coleman (noted for its efficiency in BPL testing) then the difference is only about 24%.

I should point out that one's kitchen style makes a difference here. If your backcountry culinary methods involve lighting the stove a number of times during a meal, you'll lose ground quickly via re-priming with a WG stove compared to a canister stove. And if you are not practiced, as has been noted by B.G. and others, you'll use more fuel to prime than those of us who have been using WG stoves for 35 years.

And another couple numbers, from other testing I ran:
Whisperlite, to prime and boil 4 cups water, avg. of 3 runs, 16.7 gms
Simmerlite, same test, avg of 3 runs, 17.7 gms
Note that here the Whisperlite beats the Simmerlite, while in the longer test I did that was not the case. I believe it takes more fuel to prime the simmerlite, but it burns slightly more efficiently and thus catches up in a longer burn.

Edited by paul on 08/04/2013 14:47:31 MDT.

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

Locale: Silicon Valley
Re: a few numbers esbit and white gas on 08/04/2013 14:53:23 MDT Print View

"And if you are not practiced, as has been noted by B.G. and others, you'll use more fuel to prime than those of us who have been using WG stoves for 35 years."

On one long trip, I got to the point where I was priming with about one drop of white gas fuel, and then it would run poorly through another drop of fuel until the burner began to go correctly. However, that took me most of a week to perfect the technique, and it would be completely different for any stove. It is mostly a matter of characterizing the fuel delay time.

Incidentally, you may assume that I did this to conserve fuel. No. I did it to control the amount of flare during priming. I was doing all of the snow melting and water boiling in the vestibule of a three-man tent, and I didn't want to burn the sucker down. For that matter, it was an expensive tent, so I didn't even want to toast the nylon anywhere. I had one huge piece of aluminum foil about two by two feet, and I put it against the vestibule wall where the flare would happen if it did. By cutting the priming fuel down to a drop, I got minimum flare, so minimum fuel wasted. The priming fuel that goes into heating the fuel tube is useful. The priming fuel that goes up in a flash of flame is wasted.

--B.G.--

Paul McLaughlin
(paul) - MLife
WG containers on 08/04/2013 15:02:27 MDT Print View

Harald if youare computing system weight for WG stoves, use the smallest aluminum bottle you can. That's what I do - I take my 1/2 liter Sigg bottle and then plastic bottles for the rest, My 1/2 liter Sigg Bottle is 3 oz lighter than my liter sigg bottle, and the plastic bottles I use are 1.3 oz for 500ML, so I'm saving 1.7 oz that way.

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

Locale: Silicon Valley
Re: WG containers on 08/04/2013 15:17:12 MDT Print View

It is also important to know the volume of your Sigg bottle.

For one trip, we had calculated that three of us needed to carry exactly two quarts of white gas per person. So, we flew 5000 miles with empties and then went to a hardware store to purchase white gas. I got two quarts, the second guy got two quarts, and then the third guy pulled out his bottles. They were the 22-24 ounce size, and I don't think that he knew the difference. That just eliminated some of our fuel reserve. We did OK, but it was good that we were not pinned down by a storm for an extra four days.

--B.G.--

Drew Jay
(drewjh) - F

Locale: Central Coast
Esbit on 08/04/2013 16:30:36 MDT Print View

Harold,

I am not surprised by the reports of 13-14 gram consumption for a two cup boil. What should be noted is that an inefficient esbit setup can very nearly match an efficient alcohol stove.

An efficient esbit stove such as a Caldera Cone or Snow Leopard style windscreen will boil two cups of water on 9 grams of esbit. I linked my two setups already, also see these threads for tests by Dan Yeruski and Jon Fong:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=79861

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=70489

Dan and Jon are using the 4 gram tabs. I use a different approach. I boil two cups with a 14 gram tab and then put the unburnt remainder in a small ziplock. After boiling two more cups I combine the two remainders to boil the final 2 cups. So I can boil 6 cups with two 14 gram tabs, leaving just a bit of esbit left over.

I've had extremely poor results with the Coughlans tabs. I don't know if I got a bad batch or what, but they fall far short of the 14 gram tabs in my tests.

I don't drink tea and eat at least one cold meal a day, so I calculate my fuel consumption at 18 grams per day and round up to the nearest full tablet. If I was worried about saving the last few grams I could incorporate a 4 gram tab instead of rounding up.

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: esbit and maybe white gas on 08/04/2013 18:53:21 MDT Print View

Harold,

Regarding gas versus liquid stoves: the BTU of each fuel is almost the same, so one would expect the boil times to be similar. The variable in my mind would be the efficiency of the stove being used. Maybe it would be best to test both using the same stove – say a MSR Whisperlite Universal.

Denatured alcohol and Esbit have almost the same BTU, so it would be best to test both fuels with the same stove – not really possible. However Trail Designs have cone systems that use both systems.

Here is a test for your calculations.

Caldera Cone GVP with Esbit Graham Cracker stove in a Cuben sack = 86 grams

Caldera Cone GVP with Trail Designs 12-10 stove in a Cuben sack = 92 grams
Trail Desgins 5.5 ounce fuel bottle = 19 grams
Caldera Cone complete alcohol set up = 111 grams

Test results (2 cups water at 70F). Time to bring to full boil (212F):

Esbit = 8 minutes 01 seconds (9 grams of Esbit consumed)
Sunnyside Denatured Alcohol = 8 minutes 44 seconds (11 grams used)

BTW I weighed the Esbit (my scale goes down to only full grams).
Esbit tab in package = 14 grams
Esbit tab removed from package = 14 grams
Empty package on scale = 0 grams

I am not willing to open a bunch of Esbit packages to calculate the actual weight.

Last but not least, we need to calculate the cost of fuel. White gas and alcohol are cheapest. Esbit and IsoPro most expensive. Probably doesn't matter to folks who backpack once or twice a year. If you hike a lot (as I do) it is a consideration unless you have plenty of disposable income. Then there is the cost of the stove. White gas normally the most expensive unless you get a remote canister.

Harald Hope
(hhope) - M

Locale: East Bay
great info! on 08/04/2013 19:54:00 MDT Print View

wow, really good stove information, I think I'm going to have to create a new posting on optimizing whisperlight burns, this stuff is too good to just let fade away.

It seems like there's a rough consensus then that for good esbit setups and usage, 9gm would be achievable, I'll include the links to all the stuff linked to here so people can figure it out for themselves if they are not reaching that efficiency. 9 gm is quite decent, 10 or 11 gm is I think about as good as you can get with alcohol, and then only with ethanol stuff, like sunnyside or kleanstrip green, so it's not surprising to see nick get that.

So I'll update the table, maybe I'll have two items, good esbit/average esbit. The table rows take a while to create, which is why I wanted to wait to see what people got as results.

Bob G, I know exactly what you mean about priming inside the tent or vestibule, many is the time I've done that in the rain with white gas, xgk or whisperlight, though I wasn't quite as clever in my solution, I did not however burn the tent, somehow, I think I used a pot over the flame, can't remember how I did it, but I do remember the problem.

The tip on optimizing the whisperlight int'l is really good, thanks peter v, again, these tips are too good to leave lying so I'll think of something to do with them.

The point of relative costs is worth noting too, obviously white gas and alcohol will be cheapest, since you can buy them by the gallon.

If I can get 17gm whisperlight 4 cup boil without modifying the stove, I'll update those rows, but it's also tempting to test the whisper intl to see if I can get the results peter v gets via mods. It's hardly fair, after all, to run highly optimized cone/screen/burner setups for esbit/alcohol and not see how good you can get the gas/white gas systems. already these numbers are far better than what the earlier bpl tables showed, so it's worth taking another look at the things. I see no real reason why a remote canister would not benefit from the same type of screen customization/optimization that I did for the alcohol stoves, the principles are similar.

Harald Hope
(hhope) - M

Locale: East Bay
interesting on 08/06/2013 15:13:32 MDT Print View

I decided to test 4 cup boils on a variety of alcohol stoves after the unexpected results from the whisperlight. The results here were also unexpected. Blame Feynman, he notes you need to question assumptions by testing, even if someone else has tested before, and to carefully control the variables, particularly the wind screen, as sgt rock learned too.

MB is not correct that the stove type does not matter, they matter quite a bit, however, the results are interesting. All tests were done with an ion stove type screen, 4" high, 1/4" gap between screen and pot, about 3.5 sq" of air inlet holes. 1.3 L evernew uncoated pot. The wide pot lets me use the cat stove, and the standard penny, which you cannot use efficiently if at all with a narrow pot. All tests use SLX denatured alcohol, normal type. All tests done at about 70F air temp, 70F water, sea level plus a few hundred feet.

[changed times/quantities after more testing with revised screen)


  • jim wood style fancy feast stove, with jim wood style base: 6:15-7:00 to boil, 35 ml/28gm fuel, boils for 30-60 seconds. Clear choice if you want your food/beverage fast for not a huge penalty in fuel consumption. Easy to use, but requires priming before you put the pot on it. Not hard to do, but it loses about 30 seconds of burn that way.

  • penny stove, 12 oz can size, 6 jets point out, 7:45-8:30, 1+ minute boil, 30 ml/24gm fuel. Requires priming, but you can put the pot on it as soon as it's lit since it has a stand. The penny does much better on a wide pot, and with a larger amount of alcohol to start than it does with a narrow pot and less alcohol. 35 ml boiled the water for a bit over 2:30, solid boil.

  • ion stove, 17:30-18:30 min, about 1 minute weak boil, 25ml, 20gm (pot must have a real lid to get this boil, heavy enough to keep pressure in). No priming required, but this is probably longer than most people want to wait for 2 people.


I believe however that you can break alcohol stoves into types, by speed/efficiency, so you can find the simplest stove within each type, these three basically represent those types, very fast but not as efficient, reasonably fast and efficient, and very efficient but slow. As you can see, there's a roughly 10ml / 8gm range between most efficient and less efficient for 4 cup boils.

The wind/heat screen is very easy to use and carry, which makes to my mind the need for a cone questionable. High ethanol fuels like sunnyside or kleanstrip green should be about 10% better, methanol, pure, about 10% worse re fuel consumption.

Much to my surprise, all of these numbers except the ion are totally acceptable for 2 people in terms of both time and fuel consumption, in fact, I will have to update the page to note this for 4 cup boils. So you can very comfortably use an alcohol stove, if you have the right type/screen and get the same exact benefit as the ion solo 2 cup narrow pot, in other words, for 8 cup per day boils, the right standard alcohol stove/screen setup will also never be heavier than gas stoves, and will cook the food in a completely reasonable amount of time.

Edited by hhope on 08/06/2013 20:44:41 MDT.

Jon Fong
(jonfong) - F - M

Locale: FLAT CAT GEAR
Re: interesting on 08/07/2013 09:00:51 MDT Print View

Harold

PM me your mail address and I will send you a sample stove to test. Jon

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
WG on 08/07/2013 11:37:59 MDT Print View

Yeah, the older SVEA is a great little stove. Neither the Whisperlite nor the Simmerlite can come close to it for efficiency. On hissing (not puttering) low I get about 3quarts per ounce counting initial priming 3 times. I measured .23oz per quart (average for 5 runs) in the kitchen, but field use is more like .28-.30 per quart.
(Why quarts? Because the maximum fill on the pot is 1 quart, NOT one liter.) All started from 40F water, and I called a boil at 210F. I could typically get only about .75oz per liter with the older Whisperlight and slightly worse with the Simmerlite (I seem to remember about 7/8oz per liter.)

I normally use a tight fitting windscreen with a wider 4"+ sqin gap in the bottom. Note that 1qt is about it, it will overheat with more. I also use a light aluminum grease pot ( 4 cup filled to about 1/4" below the brim.) It has a series of rings pressed into the bottom to act as a heat exchanger, or maybe more to increase the surface area of the bottom by about 20%. It weighs about 94gm including the lid.

The only problem is the stove is heavy. I keep saying they need to make a ti version...

Anyway, at my usage, I need to get 5gm/liter out of a remote canister stove to be lighter. Neither the Windpro, nor Coleman F1 do that. I am hoping Rogers FM300T version will. Again, I will be using a tight fitting wind screen with wide air inlet's and the same pot.

Harald Hope
(hhope) - M

Locale: East Bay
esbit added on 08/07/2013 18:31:45 MDT Print View

The backpacking stove fuel consumption / carry weight tables now include two esbit entries, one for consuming 9 gm per 2 cups, and one for 14 grams, ie, one tab.

I used Drew's 42 gram setup because it's solid, supports a standard full sized pot, and does nothing more than needed. People with Cones can just add the extra weight of the system, if present, to the daily/nightly totals to get the weight comparison.

I included in an appendix the good white gas tips, and cleaned up/rearranged the article to make it a bit more readable, though it's gotten pretty long with esbit and white gas added.

Esbit wins, but I also include a note / warning about the toxicity of the esbit fumes. I don't think I'd use esbit if I thought there was any chance of having to cook in a tent.

Also adding a rough cost too for each fuel type.

James M, I agree, I think msr and optimus/svea are really dropping the ball on this, if you look at for example roger caffin's work on his ultralight remote canister, it shows what can be done to lighten these setups fairly substantially, but they haven't touched their designs in years. I guess in that sense the term 'dinosaur' fits, it's odd how these corporations get all conservative when they were built on creating the best stuff out there.I see no reason they can't make a 6 oz white gas stove system, with aluminum fuel bottle, for example, built on the principle of efficiency over speed.

Edited by hhope on 08/07/2013 21:55:55 MDT.

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: esbit added on 08/11/2013 18:57:47 MDT Print View

Yeah, Primus/Optimus are really slow to make any sort of inovation. Especially when it seems like a loosing proposition.

But 4oz of fuel is way more than needed for cooking a typical breakfast for one or two people. Including about a quart and a half of cooked coffee (perked for 7 minutes,) boiled another quart of water for three kids and 2 adults, a pound of bacon and a dozen eggs for 9 people on 2oz of fuel. The valve/expansion chamber could easily be aluminum, with a smaller ti tank. I believe the whole set-up would hit your 6oz mark. This pretty much eliminates the need for the aluminum bottle and pump.

Anyway, propane and WG have nearly the same BTU quanta (about 5% more for the typical butane fuel.) It is too bad the canisters weigh so much and are so unreliable. Anyway, I agree there is a lot of things that can be done with higher BTU fuels. Butane/iso-butane is actually only slightly better than alcohol, after considering the canister. Stove weight is the big killer with WG stoves. Esbit is messy on the pots.

Bob Shaver
(rshaver) - F

Locale: West
Field test of three stoves on 08/16/2013 16:27:27 MDT Print View

I was on a trip where we could compare a Caldera cone (alcohol) Canister (MSR Pocket Rocket) and a JetBoil. My conclusion was any difference was too close to call. Other considerations and personal preferences mattered more than just weight. The link to the comparison is here:

http://backpackingtechnology.com/food-and-cooking/a-stove-comparison-alcohol-caldera-cone-vs-canister-jet-boil-pocket-rocket-giga-power/

Some mesurements:

Caldera Cone weights:

Total weight, stove, pot and fuel, at start of trip: 36.1 oz
Total weight, stove pot and fuel, at end of trip: 18.1 oz
Note: we had 3 oz of fuel left over.

JetBoil:

Total weight, stove, pot and fuel (one 220 g canister) at start of trip: 28.2
total weight, stove, pot and empty fuel canister at end of trip: 20.2 oz (weight of empty fuel container = 5.6 oz)

Pocket Rocket:

Total weight, stove, pot and fuel (one large and one small canister), at start of trip: 33.1 oz
Total weight, stove pot and fuel, at end of trip: 22.2 oz

Considerations besides weight: Its hard to fry fish in a JetBoil. You can't bake with either JetBoil or PR. Wind can and did make the Pocket Rocket inoperable. You can lose a whole canister of fuel at one stroke if the valve is not shut off. Its easy to tip over a Pocket Rocket with a pot of boiling water on it and we did on this trip. You can't beat the JetBoil for speed to boil, but does anyone care? So if the difference is + or - 6 oz on a week long trip, I'm going for the reliability and versatility of the Caldera Cone.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: he's gotten sloppy on 08/16/2013 18:20:24 MDT Print View

Hi Harald (and Bob)

I am not sure how many white gas and kero stoves I own. 'A lot' would be a simple answer. Most of the expected ones for sure. Very bluntly, I get given many of the new ones for review: cost is not an issue. And I have tested them all.

I have used white gas for years, but did not like the unexpected whoomps which sometimes happened. They can be upsetting in the snow in a tent. So I moved to kero for many years. Various stoves, but I found the Coleman Peak Apex II was one of the best as it has 2 valves. I have a couple of these in various states of heavily used or nearly worn out. I was actually repairing one of them on and off as some of the frailer parts died in the field.

However, my wife was always a bit scared of the WG stoves - we have both seen many accidents. Burnt packs, sleeping bags tents, and bits of skin. Not, I will add, due to my efforts. She suffered the kero stoves but seriously disliked them because of the smell they made and the way the fumes upset her nose when I was cooking dinner in the vestibule.

Then I was asked to do a survey of various sorts of stoves - WG, kero, canister, alky & Esbit. I was a bit astonished to find that the modern canister stove can be more powerful than most any WG/kero stove. Most of the WG stoves are limited in power to under 2.8 kW for technical reasons which the vendors never explain - it's to do with the fuel/air mixing process. Some of the canister stoves can reach 3.3 kW. The myths of low power probably trace back to the days of the Bleuet stove, which was underpowered. Mind you, running any stove flat out is very wasteful.

Then I looked at the fuel consumption. Yes, if you take a running WG stove under test conditions it may have a similar fuel consumption per litre boiled to a canister stove. But in Real Life, looking at hard data on fuel consumption over many long trips, I found that WG needed about 50% more fuel. The rest goes in priming and leaving the stove running between cooking. That's not theory; that's carefully recorded data from field use.

In answer to Bob, I think I can get a WG or kero stove going with very little waste - I have had a lot of practice with both. But even so, I was using more WG or kero.

During the survey, in the field, my wife was taken by the lack of smell, the safety (lack of fireball priming) and the speed of cooking which we got from the canister stoves. I don't apologise for using the 'fireball' word: you will find it in the XGK instructions.

Then I looked at the weights. Yes, there are heavy stoves of all sorts. Yes, the metal gas canister has extra weight. But the tank and the pump for a WG stove also weigh a lot. The remote canister stoves are in general much lighter than the WG stoves: the one I have developed weighs under 90 grams. Add a 68 g Powermax canister for fuel. That's light. That's fast to get going. That's very convenient in use. That's powerful. That's seriously controllable down to an extremely low simmer too.

Yeah, I'm biased. Now you know why.

Cheers

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: Re: he's gotten sloppy on 08/20/2013 22:39:05 MDT Print View

I have read everything that Roger C has written... a lot of good stuff. I was not surprised with the results as gas and liquid (WG) have about the same BTU. Gas does not need priming. I can run a Svea 123 with very little fuel to prime it and usually perfectly time it to get the stove to light at exactly the time the priming flame burns out -- but it is fuel not used for cooking.

In cold weather the Svea is not ideal, but it works. I hate the flare-up with the MSRs, and a Roger states, MSR says it is normal.

So a properly designed remote canister is going to work in cold. To me it just comes down to preference, although I am more comfortable with a WG in cold because of lots of experience and familiarity. But I am using my WindPro II more and more in winter. I know there are lighter options.

I still think the Svea is the best stove ever made... little maintenance and never failed me in decades of use.

My go to 3 season stove is a Caldera GVP with Esbit. But I still occasionally take the Svea, it is like a trusted old friend.

P.S. I never have had an accident with a WG stove or burned anything :)

Stuart R
(Scunnered) - F

Locale: Scotland
Re: he's gotten sloppy on 08/21/2013 06:06:13 MDT Print View

"do not attempt to prove things to confirm your existing bias"

I think you failed on that score. To illustrate with just one point:

"Simmering a lot? – Forget it, bring alcohol stove!

Important! Simmering performance on canister/white gas stoves is dismal, if you simmer then alcohol completely decimates canister efficiencies. Sample: 8 gm fuel, ion stove, simmer ring added: 32 minutes simmer. I saw one canister number online for 8 minutes simmer, 7 gm fuel. So there’s literally no comparison at all once you start simmering.
"

You base canister gas consumption on just one unreferenced online quote.
When I am dry-baking a loaf of bread, I use less than 10g gas for 30 minutes cooking time.
Most people do not realise just how low a canister stove can go.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Re: Re: he's gotten sloppy on 08/21/2013 11:57:29 MDT Print View

>"Most of the WG stoves are limited in power to under 2.8 kW for technical reasons which the vendors never explain - it's to do with the fuel/air mixing process. Some of the canister stoves can reach 3.3 kW. The myths of low power probably trace back to the days of the Bleuet stove, which was underpowered. "

I'll confirm the above. 20 years ago, I was experimenting with WG stoves to up their output from stock 8,000-10,000 BTU/hr (2.3 - 2.9 kW). Different orifice sizes, burner configurations, and I could sometimes get 10-15% more heat output but things were pretty ugly - unstable flames, poor efficiency as evidenced by soot production, flare-ups, etc. Really, the solution for my problem was to bring more stoves - six in all. The other solution was to go with the ultimate "canister stove" in the form of a propane-fired weed burner or 100,000 BTU/hour (29kW) stove burner (think Chili Cook-off in a 55-gallon drum). Empty tank weight sucked (a pound of steel per pound of propane) and the tank would quickly ice up, but pouring hot water on the tank or directing a small plumber's torch or BP stove at the tank defrosts it nicely (Do not try this at home, kids, mostly because directing flames at fuel tanks freaks most people out).

The six MSR WG stoves got the Backpacking Hot Tub Mark I up to temperature, but it took 4 hours. Met my wife on that trip. The Snow-Camping Mark II version with the propane burner was at 40C/104F in 40 minutes.

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Re: Re: he's gotten sloppy on 08/21/2013 15:02:17 MDT Print View

David - many years ago I went to a lecture by an American guy about space optics. Anyway this guy had worked on Reagan's Star Wars project where they were trying out chemical lasers - hydrogen fluoride or sodium fluoride I think. They tested these lasers by firing them into a tank of water the size of an Olympic swimming pool which was heated to boiling in a few minutes.
You didn't by any chance work on the same project....?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: he's gotten sloppy on 08/21/2013 15:46:01 MDT Print View

Hi David

> I was experimenting with WG stoves to up their output from stock 8,000-10,000 BTU/hr
> (2.3 - 2.9 kW). Different orifice sizes, burner configurations,
The longer chain molecules need a lot more oxygen for full combustion, as you know. Even an XGK is limited in it's ability to draw in the necessary amount of air. If you pressurise the air supply into the pre-mix section you can do better (I have done that), but otherwise is is hard.

One route which might work would be to switch to a ring burner: that would allow a number of smaller flames to each suck in their own air supply. That gets heavy and complex though.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: he's gotten sloppy on 08/21/2013 15:53:08 MDT Print View

> Important! Simmering performance on canister/white gas stoves is dismal, if you
> simmer then alcohol completely decimates canister efficiencies.
I will add to what Stuart wrote.

I can turn most any canister stove down to such a low simmer that it is hard for the pot to even reach boiling point. Even with a lid on the pot (and a windshield), normal losses can be more than the heat output of a canister stove turned really low. There should be a graph about this in one of my stove articles, but I forget where.

In my book, hard experimental data recorded with a thermometer beats hand-waving any day. But that is just me.

Cheers