Hanging Stove project

8:19 p.m. on June 26, 2011 (EDT)
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I am not a climber and probably will never be, I enjoy fiddling with stove design.

I became interested in hanging stoves a few weeks ago after reading a comment about hanging stoves on an Australian Bushwalking forum, the comment reminded me of liquid feed stove system I started working on about five years ago, as can be seen from the photo I put a Pocket Rocket stove on the base of an upside down canister, part of the idea in doing this is in very cold conditions there is an option to put some of the reflected heat back into the canister, for some reason I shelved this idea until now. While I do not climb I can see some advantages of  hanging stoves in some cases in backcountry snow camping.


IMG_1068.jpg

A concept prototype

I started my recent hanging stove project by making a simple hanging stove bracket to hold the canister upside down, I then made some legs and a pre-heat tube modification for a Gnat Ti stove (called Kathmandu Backpacker Stove Titanium here in OZ), the legs have been made to clip on the base of the canister. This worked well except the Gnat stove has something wrong with it and I have difficulties with simmering in both the upright canister configuration and liquid feed configuration., I have since replaced the Gnat with my favorite a Kovea Supalte Ti stove and all is working well.


IMG_4573.jpg

A simple hanging system using a Gnat stove

My cheap remote canister stove then turned up and with the current hanging plate the new stove fitted very nicely on the base of the canister, but I will point out that at the moment this is just playing with design and I realize that with this system would be difficult to fit a wind shield and pack away.


IMG_3350.jpg

Hanging the Chinese stove

The next part of my hanging stove project was to use a JetBoil Personal Cooking System (PCS) with a liquid feed modification that I had done a number of years ago will before JetBoil came out with the Helios I have used my modified JB stove in winter in Australia a few times so I know that it works in cold conditions.


IMG_3340.jpg

Liquid feed mod


I needed to hang the canister on the base, so I machined up a bracket that screwed onto the plastic shroud, the bracket takes the std JB 100g canister, I did the machining so the canister clips in so it does not fall out while it is still easy to put in, and that it would still fit into the JB PCS pot.


IMG_3344-.jpg

Remote canister JetBoil PCS hanging stove

I then needed some way to hang the JB stove, I did not want to buy a JB hanging kit as they are expensive here in OZ, so I got a some spare tent poles and some SS wire form the local fishing store and made a rough copy, while the hanging kit is OK for display purposes I would not like to assemble it on the side of a cliff at -20ºC, some more design thoughts needed here.


IMG_3343.jpg

All packed up

Where to next, as I am not a climber but I have been doing some research on hanging stoves to try and understand what is needed, I have also been in contact with a British Climber to try and get an understanding of what is needed. So far I have found a few ideas, one is using a larger pot as the windshield, this seems to be very popular and I have seen this done with backpacking stoves, I have also found that my idea of hanging the canister upside down under the stove is not a new, it was done very nicely to a WindPro stove by Longshanks in Denver and the idea posted on a climbing forum last year. http://students.washington.edu/climb/forum/viewtopic.php?f=19&t=5759&start=0

I am combining this project with one that I have been thinking about doing for a while and that is windscreen design.

This project will continue.

6:14 a.m. on June 27, 2011 (EDT)
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very cool!

8:23 a.m. on June 27, 2011 (EDT)
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Really neat idea, keep us updated on your progress.

4:14 p.m. on June 28, 2011 (EDT)
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I'm I seeing things correctly?  A Jetboil in inverted canister mode?  A pocket rocket in inverted canister mode?  NOW that's cool.  Liquid feed is unquestionably the way to go in colder weather.

How stable is that PR when in inverted mode?  Seems like it might be a little tippy, yes?  Still, a brilliant idea.

HJ

8:11 p.m. on June 28, 2011 (EDT)
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hikin_jim said:

I'm I seeing things correctly?  A Jetboil in inverted canister mode?  A pocket rocket in inverted canister mode?  NOW that's cool.  Liquid feed is unquestionably the way to go in colder weather.

How stable is that PR when in inverted mode?  Seems like it might be a little tippy, yes?  Still, a brilliant idea.

HJ

 Hi HJ,

Yes you are seeing things correctly, I originally started playing around with the PR, and made several different liquid feed designs, I then started to make complete stoves from scratch, burners, valves, jets and pot stands.

My original inverted PR stove (pictured in original post) was done many years ago and I was just prototyping an idea, it was never intended for use, the stand was something I quickly made to take a photo.

I agree that liquid feed is the way to go in colder temps, I still use an upright stove in the warmer months, I find the uprights much simpler to use than liquid feed stoves.

Tony

11:21 p.m. on June 28, 2011 (EDT)
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TonyB said:

Yes you are seeing things correctly, I originally started playing around with the PR, and made several different liquid feed designs, I then started to make complete stoves from scratch, burners, valves, jets and pot stands.

My original inverted PR stove (pictured in original post) was done many years ago and I was just prototyping an idea, it was never intended for use, the stand was something I quickly made to take a photo.

Very cool stuff. Very professional look. Thanks for sharing it.

I agree that liquid feed is the way to go in colder temps, I still use an upright stove in the warmer months, I find the uprights much simpler to use than liquid feed stoves.

The regular uprights are indeed a snap to use, and as long as your fuel's temperature stays above about 40F/5C, there's really not too much reason to use a liquid feed gas stove unless you want the improved stability and wind resistance of a remote canister set up or something like that.

Which brings me to a question. Have you tried starting your remote canister stoves in liquid feed mode? The instructions I've read from Primus say to start them in vapor feed mode, let them warm up a minute, and then invert the canister. Starting a stove in vapor feed mode will of course cause the propane to burn off faster than the isobutane, changing the fuel mix over time and degrading cold weather performance.

I've been thinking about experimenting with starting a remote canister stove in liquid feed mode just so that my fuel blend stays consistent throughout. However, since it's summer here, I have to wait six months before I can start valid experiments. I was wondering if you've ever tried it.

I think it should work OK. Starting my Coleman Xtreme in liquid feed mode works just fine. I'm suspicious that the advice from Primus is more to avoid litigation than to get the stove started properly. Even if it were to flare up briefly, so what? If I can handle priming a liquid fueled stove, I should be able to handle whatever small (by comparison) flare up a gas stove might produce, yes?

HJ

1:04 a.m. on June 29, 2011 (EDT)
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hikin_jim said:


Which brings me to a question. Have you tried starting your remote canister stoves in liquid feed mode? The instructions I've read from Primus say to start them in vapor feed mode, let them warm up a minute, and then invert the canister. Starting a stove in vapor feed mode will of course cause the propane to burn off faster than the isobutane, changing the fuel mix over time and degrading cold weather performance.

I've been thinking about experimenting with starting a remote canister stove in liquid feed mode just so that my fuel blend stays consistent throughout. However, since it's summer here, I have to wait six months before I can start valid experiments. I was wondering if you've ever tried it.

I think it should work OK. Starting my Coleman Xtreme in liquid feed mode works just fine. I'm suspicious that the advice from Primus is more to avoid litigation than to get the stove started properly. Even if it were to flare up briefly, so what? If I can handle priming a liquid fueled stove, I should be able to handle whatever small (by comparison) flare up a gas stove might produce, yes?

HJ

 Hi HJ,

I do start my inverted canister stoves with the canister inverted, with no problems but I am careful and always have a lighter or match lit when I turn the valve on, there is no other option with the extreme.

I agree some manufacturers are very cautious, like JetBoil only recommending to fill the PCS pot to 500 ml, lawyer driven camping.

Tony

2:28 p.m. on June 29, 2011 (EDT)
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TonyB said:

I do start my inverted canister stoves with the canister inverted, with no problems

Ha! I suspected as much. Didn't really make sense to me that I can start an Xtreme without using vapor feed but couldn't with other stoves operating on the same principles. Thanks for sharing your experience.

lawyer driven camping.

Sadly true. :(

HJ

6:02 p.m. on June 29, 2011 (EDT)
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Re: Hanging Stove project, Part 2, windshield tests

Wind can have a major impact on the efficiency of a camping stove, as part of my hanging stove project I will be looking into windshield design.

last weekend I ran some wind tests on the Liquid Feed (LF) JetBoil (JB) stove that I have modified for the hanging stove.

Test procedure.

Part of the LF JB hanging stove design is that it does not have to be hung, it can be used as a normal remote canister stove, for these test I used the stove as a remote canister stove.


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JBLF stove on test bench note: thermistor in lid


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Old Vane Anemometer

The stove was placed on the test bench with a small pedestal fan placed a meter away, the wins speed was measured with a (very old) Vane Anemometer, the wind speed was measured at around 12kph (note, the wind speed feels faster that 12kph but I have not had the Vane Anemometer calibrated) I then attached the stove to the canister and took note of weight (all weight measurements 0.1 grams resolution), measured 500g of water in pot, replaced lid.


IMG_4577-1.jpg

Pedestal fan (in very messy garage)

I placed stove on the test bench, I then placed the thermistor in the pot at 1 cm from bottom, started data logging program and at 10 second I turned the gas on and lit the stove, I then adjusted the flame to a high flame setting, when water temperature reached 95º I turned the stove off, removed pot and re-weighed canister, noting the new weight. From logged data start temp was noted and fuel used, the fuel used was then normalized to grams of fuel used per 80º (g/80C)


IMG_4578-1.jpg

Testing MSR windshield


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Testing Caldera Cone windshield

The tests

The first test were with no windshield and no wind, this is used as a base line figure.

Results, fuel used per 80ºC = 6.1 g

The second test was with the fan turned on but no windshields.

Results, fuel used per 80ºC = 8.2 g

The third test was with fan on and using an old MSR windscreen, which was placed completely around he stove and pot leaving around 1.5 cm gap and secured together with a clip.

Results, fuel used per 80ºC = 7.4 g

The fourth test was using a Trail designs Caldera Cone windscreen, on some of my previous wind tests this windscreen performed extremely well,  this windscreen is designed for a BPL Ti 550 pot and was too small to fit over the JB pot with the cozy on it, so I placed the windscreen as best as I could around the pot with the gap opposite the fan, the fuel line came out this gap.

Results, fuel used per 80ºC = 6.9 g

Below is the heating rate graph, the fastest boil (pink line) is the test with no wind the slowest is the test with wind but no windshield (blue line).


Wind-tests.jpg

Discussion of results.

First I wish to point out that these tests are not what I would call scientific, I only did one run per test and with canister gas stoves they are very hard to adjust to repeat runs, but there is a trend that fits in with what I was expecting.

The result clearly show that there is a reduction of efficiency with the introduction of wind (I know not new information), and that a windshield does make a difference (again not new), but I am surprised how little loss of efficiency the JB system has with no windshield, from past tests with a normal upright stoves with no windscreen there was a much higher loss of efficiency, I am also surprised with this system what little difference a windshield made to the efficiency and the test with the CC windshield was only marginally better that the MSR windshield.

Next tests: I hope to test a Trangia windshield system, which will be fitted with a canister stove.

Tony

2:00 p.m. on June 30, 2011 (EDT)
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Tony:

Very interesting stuff. 

I understand what you mean about the results not being exactly scientific.  When I've run various fuel consumption and boiling time tests, the results are often mixed.  It takes quite a number of tests before any solid patterns emerge.  I usually don't include fuel consumption or boil time (not that boil times are particularly relevant) figures when I review a stove.  It simply takes too much time to compile reliable figures.

Nevertheless, your results are still interesting, particularly your finding that not using a windscreen mattered less than you expected.  I'm a little surprised as well, but not entirely.  In other tests I've seen published, the Jetboil PCS has shown that its design has an innate wind resistance.

Had your tests been performed with a GCS pot, I think you would have seen very different results.  The GCS's heat exchanger is fully exposed and therefore far more vulnerable to wind.

HJ

P.S.  I like the "traditional" style remote canister set up on the JB even better than the hanging kit.

8:07 p.m. on June 30, 2011 (EDT)
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hikin_jim said:

Tony:

Very interesting stuff. 

I understand what you mean about the results not being exactly scientific.  When I've run various fuel consumption and boiling time tests, the results are often mixed.  It takes quite a number of tests before any solid patterns emerge.  I usually don't include fuel consumption or boil time (not that boil times are particularly relevant) figures when I review a stove.  It simply takes too much time to compile reliable figures.

Nevertheless, your results are still interesting, particularly your finding that not using a windscreen mattered less than you expected.  I'm a little surprised as well, but not entirely.  In other tests I've seen published, the Jetboil PCS has shown that its design has an innate wind resistance.

Had your tests been performed with a GCS pot, I think you would have seen very different results.  The GCS's heat exchanger is fully exposed and therefore far more vulnerable to wind.

HJ

P.S.  I like the "traditional" style remote canister set up on the JB even better than the hanging kit.

Hi HJ,

I have spent a lot of time trying to get consistency in my stove tests, for canister stoves I fitted a graduated dial to a PR stove, this allowed me to accurately replicate the opening of the control valve, I ran many tests, made sure all the parameters where the same, ambient temp, canister temp, water temp, bench top temp, no wind and could never get a repeatable result, sometimes the results varied a lot.

I have also done a "lot" of tests on alcohols and alcohol stoves and again I have been very careful to make sure all of the parameters are the same, and the results are still all over the place.

After discussions with Roger Caffin who has experienced the same problems, I came to the conclusion that the alignment of planets and the moon are to blame.

But seriously, as you mentioned after a while, patterns in the results do appear and you can usually know what to expected in the results.

My data logging is done by Labview Data Acquisition (DAQ) program on a computer, it is very easy to analyze the results in Excel.

I have done wind tests with the GCS pot but it was a while ago and I do not have the results on me, I will redo them on the weekend and post the resluts.

Below is a photo of the LF JB stove in the snow, the stove was left outside all night and worked perfectly, the other photo is a liquid feed stove I made from two Pocket Rocket stoves.


DSC01745.jpg


DSC01750_1.jpg


Tony

1:32 a.m. on July 1, 2011 (EDT)
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Both excellent looking stoves.  I like the Powermax canister set up for the JB.  It must give really good cold weather performance, yes?

Although since you're using Kovea canisters which are 70/30 iso/pro, you'd probably get nearly as good performance out of the Kovea powered set up, yes?

The duo PR set up looks nice and light as well as being compact. 

With the GCS pot, I'm assuming you'd use a windscreen, yes?

HJ

6:29 p.m. on July 1, 2011 (EDT)
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hikin_jim said:

Both excellent looking stoves.  I like the Powermax canister set up for the JB.  It must give really good cold weather performance, yes?

Although since you're using Kovea canisters which are 70/30 iso/pro, you'd probably get nearly as good performance out of the Kovea powered set up, yes?

The duo PR set up looks nice and light as well as being compact. 

With the GCS pot, I'm assuming you'd use a windscreen, yes?

HJ

 Hi HJ,

The PowerMax canister and the JB PCS stove system does  work very well in the cold but I for some reason I prefer my Extreme.

I have never had a problem with the Kovea gas or stoves even in mid winter, the best thing with the Kovea gas canisters is that it is much cheaper than MSR and JetBoil canisters.

I do not use the double PR anymore, to many stoves.

I will do some windscreen test with the GCS pot this weekend.

 

BTW, the GCS pot is the most efficient fuel pot that I have tested with both alcohol and gas.

 

Tony

 

7:06 p.m. on July 3, 2011 (EDT)
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HJ asked the question.

Had your tests been performed with a GCS pot, I think you would have seen very different results.  The GCS's heat exchanger is fully exposed and therefore far more vulnerable to wind.

I ran some wind tests on the Jet Boil Group Cooking System (GCS) on the weekend.


IMG_4619.jpg

GCS no windscreen

Testing method

These test were done slightly different than the PCS tests as I ran the remote canister in upright configuration, I decided to do this to try and get better consistency in the tests, to do this I put a adjustable valve on the canister and ran the JetBoil stove until the flame at a high level and was stable I then only used the valve on the canister to turn the stove on and off. My STD 0.5 liters of water were used. The wind speed measured was around 12-15 kph.


IMG_4620.jpg
GCS with old MSR windscreen

Results

Test 1, GCS pot and remote canister JetBoil stove, no wind and no windscreen/

Fuel used in grams per 80ºC = 5.0g

Test 2, wind with windscreen, stove was lit then windscreen placed around stove, then fan turned on.

Fuel used in grams per 80ºC = 5.5g

Test 3, wind, no windscreen, During this test it was obvious that it this system is greatly effected by wind and to raise the water to 95ºC was going to take some considerable time and fuel, I stopped the tests at the same time as the no wind test and as the heating rate is usually linear I extrapolate the results.

Fuel used in grams per 80ºC = 25.4g


JB-GCS-wind-tests-heating-rate.jpg

Heating rate graph, pink line no wind/ no windscreen, blue line, wind/windscreen, yellow line wind/no windscreen

Discussion of results.

As can be seen from the fuel used in the wind/no windscreen test the GCS stove efficiency is affected quite a lot by wind but the use of a windscreen does improve the efficiency and possibly if the windscreen is setup properly wind may have no effect, the difference between the results of the no wind and wind/windscreen tests is very small this difference could be considered in normal testing error.

Conclusion.

The GCS stove system efficiency is affected by wind but the use of a good fitting windscreen can greatly improve efficiency to the point that the wind may have no effect.

Tony

12:11 a.m. on July 13, 2011 (EDT)
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Wow!

I'm sorry I haven't  been on the site lately.  These are GREAT results.  I had heard of people unable to achieve a boil using a GCS pot in windy conditions.  Now I know that is no exaggeration.  If I'm understanding your results correctly, it took approximately five times more fuel in windy conditions with the GCS pot to achieve the the same results.  That's a HUGE difference.

The weight of a windscreen is surely justified, and with your remote set up, perfectly safe to use.  Even without a remote set up, a windscreen could be employed if one were to monitor the canister's temperature closely.

QUESTION:  Have you ever had problems with the neoprene sleeve on the GCS pot melting when using a windscreen?  Have any of the components on the burner itself melted when using a windscreen?  I've always wondered how tolerant of heat the various components would be since they were not intended to be used with a windscreen.

Changing the subject slightly, I wonder if the GCS pot will be discontinued now that the new 1.8L Jetboil Sumo pot is available.  The Sumo has some of the same built in wind resistance that a PCS pot has and also locks onto the burner base directly without having to use the cheesy little stamped steel adapter. 

HJ

6:16 a.m. on July 13, 2011 (EDT)
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Hi HJ,

 If I'm understanding your results correctly, it took approximately five times more fuel in windy conditions with the GCS pot to achieve the the same results.  That's a HUGE difference

Yes that is correct, a normal upright stove without a windscreen is even worse (more results soon).

The weight of a windscreen is surely justified, and with your remote set up, perfectly safe to use.  Even without a remote set up, a windscreen could be employed if one were to monitor the canister's temperature closely.

Yes, agree.

QUESTION:  Have you ever had problems with the neoprene sleeve on the GCS pot melting when using a windscreen?  Have any of the components on the burner itself melted when using a windscreen?  I've always wondered how tolerant of heat the various components would be since they were not intended to be used with a windscreen.

No, I have never had a problem with the neoprene sleeve melting o a STD GCS and PCS pot setup, I have melted a sleeve on a modified PCS pot.

My PCS pot sleeve is damaged, I left it setup in a hut one night and a hut rat ate part of the sleeve and some of the plastic off the handle, it also stole my mates mug left on the fire place mantle piece.

Changing the subject slightly, I wonder if the GCS pot will be discontinued now that the new 1.8L Jetboil Sumo pot is available.  The Sumo has some of the same built in wind resistance that a PCS pot has and also locks onto the burner base directly without having to use the cheesy little stamped steel adapter. 

Interesting question, JetBoil are working hard on improving their range.

 

Tony

7:04 p.m. on July 13, 2011 (EDT)
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Interesting that a "regular" upright canister stove loses even more heat than the GCS.  I would have thought that the exposed heat exchanger on the GCS would carry away a lot of heat.  Perhaps the JB's burner design combined with the GCS heat exchanger combine to provide a modicum of protection?  If you look at this photo of yours, you can see that there would be some slight shielding provided by the fins of the exchanger.  Perhaps this slight shielding compensates to some degree for the heat lost by the fins themselves.
IMG_4619.jpg

I'll be interested in seeing your numbers for "regular" upright canister stoves.

It's tougher to use a simple, stand-on-the-ground MSR type windscreen on upright canister stoves since the flame sits fairly high, particularly when the stove is mounted on a 230g or 450g canister.  With the taller configurations one either has to carry an outlandishly tall windscreen or one has to find a way to suspend the windscreen from either the stove or the pot.  I haven't quite got this set up figured out the way I like.  What are you using?

By the way, did you ever do any experimenting with a Trangia type windscreen with a canister stove?  I know you were talking about doing something along those lines at one point.

I'm also curious how you're refilling Coleman Powermax canisters.  I'm refilling Camping Gaz CV360 canisters with a Brunton Fuel Tool and standard threaded canisters with a refiller I bought from an eBay seller in Japan.  He also sells Powermax refillers, but they're quite expensive, around $60.00 if I recall correctly.  For $60.00, I can buy a dozen or so canisters, so it's quite a while before I break even.  Plus, the refiller works off of the cheap "long" 100% n-butane cans.  Refilling a Powermax canister with 100% butane would nullify the Xtreme's cold weather capability.

HJ

9:49 p.m. on July 13, 2011 (EDT)
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Ran across this while looking for a canister lantern and thought with all the liquid feed stuff here you guys might like this.


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It's the 250 Liquid Lantern. Now you can see while you cook in freezing temps. If you built a flat top for it you could melt snow with it.

6:05 a.m. on July 14, 2011 (EDT)
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Hi HJ,

Interesting that a "regular" upright canister stove loses even more heat than the GCS.  I would have thought that the exposed heat exchanger on the GCS would carry away a lot of heat.  Perhaps the JB's burner design combined with the GCS heat exchanger combine to provide a modicum of protection?  If you look at this photo of yours, you can see that there would be some slight shielding provided by the fins of the exchanger.  Perhaps this slight shielding compensates to some degree for the heat lost by the fins themselves.

My thoughts are that the flux rings do offer some protestion from the wind, any heat loss would most probably only be on the side that the wind is coming from, but the opposite side fins would have warmer gasses flowing over them.

I'll be interested in seeing your numbers for "regular" upright canister stoves.

Coming soon.

It's tougher to use a simple, stand-on-the-ground MSR type windscreen on upright canister stoves since the flame sits fairly high, particularly when the stove is mounted on a 230g or 450g canister.  With the taller configurations one either has to carry an outlandishly tall windscreen or one has to find a way to suspend the windscreen from either the stove or the pot.  I haven't quite got this set up figured out the way I like.  What are you using

I have been asked by a blogger in NZ to test Jim Woods Kite sceen design for upright stoves, which I hope to this weekend. for my uppright stoves I use a piece of tolling foil, I mostly leave an opening to check on canister temp, will post some pics on the weekend.

By the way, did you ever do any experimenting with a Trangia type windscreen with a canister stove?  I know you were talking about doing something along those lines at one point.

I have done the testing and the results will be posted soon.

I'm also curious how you're refilling Coleman Powermax canisters

I have made my own fittings, I will take some photos and post them on the weekend.

Refilling a Powermax canister with 100% butane would nullify the Xtreme's cold weather capability

I would not bother, though I have considered making my own propane-butane mix.

 

Tony

6:09 a.m. on July 14, 2011 (EDT)
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ocalacomputerguy said:

Ran across this while looking for a canister lantern and thought with all the liquid feed stuff here you guys might like this.


1261357350_401403_500.jpg
It's the 250 Liquid Lantern. Now you can see while you cook in freezing temps. If you built a flat top for it you could melt snow with it.

 Thanks ocalacomputerguy ,

 

I had not seen the liquid lantern before, it looks nice. Kovea makes a lot of MSR stoves, and a lot of canisters for MSR and other companies, parts of my Kovea stoves are excactly the same my Pocket Rocket, same size and even the same tool path machining marks.

 

Tony

 

6:30 a.m. on July 14, 2011 (EDT)
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Trangia/gas stove wind tests.

These wind tests were done with my Trangia 27-1, the stove used was  a Kovea Ti Supalite stove that has been modified by adding a pre-heat tube and stand, this allows the stove to be used in a remote canister configuration with the Trangia windscreen and base, the holes in the base were positioned away from the wind for the first WS test and into the wind for the second WS testThe pot used was the 1liter 27-1 Trangia pot.


IMG_4618.jpg

The tests were done with the canister in an upright position, to get consistency I put an adjustable valve on the canister and ran the stove until the flame was at a high level and was stable I then only used the valve on the canister to turn the stove on and off.


IMG_4615.jpg

No windscreen no wind

I placed stove on the test bench, I then placed the thermistor in the pot at 1 cm from bottom, started data logging program and at 10 second I turned the gas on and lit the stove, when water temperature reached 95º I turned the stove off, removed pot and re-weighed canister, noting the new weight. From logged data start temp was noted and fuel used, the fuel used was then normalized to grams of fuel used per 80º (g/80C)


IMG_4616.jpg

No windscreen, wind

Results

Test 1, no wind, windscreen

Fuel used in grams per 80ºC = 7.5g

Test 2, wind with windscreen, stove was lit, then fan turned on.

Fuel used in grams per 80ºC = 7.3g

Test 3, wind, base with no upper windscreen, During this test it was obvious that it this system is greatly effected by wind and to raise the water to 95ºC was going to take some considerable time and fuel, I stopped the tests at the same time as the no wind test and as the heating rate is usually linear I extrapolate the results.

Fuel used in grams per 80ºC = 53.0g

Test 4, the holes in base where placed into wind.

Fuel used in grams per 80ºC = 8.2g

Discussion of results.

As can be seen from the fuel used in the wind/no windscreen test the Kovea stove efficiency was affected quite a lot by wind but the use of the Trangia windscreen does improve the efficiency to the point where if used correctly, wind may have a very small affect on efficiency, the difference between the results of the no wind and wind/windscreen tests is very small the difference could be considered in normal testing error.

Conclusion.

The Trangia stove system with its inbuilt windscreen is very good in windy conditions but it is preferable to place the holes away from the direction of the wind.

 

Tony

10:25 p.m. on July 14, 2011 (EDT)
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422 forum posts

That's a very good control technique that you used where you opened the valve at the stove a certain set amount and then used the valve at the canister to turn the stove on and off.  Very good thinking there.  And very nice to be able to rig things up like that!

Good and interesting results as well.  It's not too surprising that a Trangia windscreen would perform well, after all it's been around for years and has hundreds if not thousands of nearly fanatical* devotees.  Interesting that with a gas stove, one should face the holes opposite the wind.  The Trangia's instructions if I recall correctly say that the holes should be faced into the wind with an alcohol stove.  Most people I talk to swear that a Trangia (with an alcohol stove) works better when it's windy.

Also not surprising that a Trangia windscreen would work well since the Trangia base and windscreen was the platform of choice for the KAP Arctic stove, the holy grail of cold weather stoves.  The KAP Arctic was developed for the Swedish military for far north operations and had a Trangia base and windshield, a special pump (that was much like the pre-Katadyn Optimus pumps, but 10 years before Optimus adopted a very similar design), and used a kerosene burner from an Optimus 111 type stove, typically the Optimus 111C or 111T type burner if I recall correctly.    Supposedly the absolutely best cold weather/high wind stove around.

HJ

*well perhaps not fanatical, but devotees for sure.

11:06 p.m. on July 14, 2011 (EDT)
81 reviewer rep
422 forum posts

TonyB said:

I have been asked by a blogger in NZ to test Jim WoodsKite sceen design for upright stoves, which I hope to this weekend.

That will be interesting to hear about. I've seen photos of Jim Woods' kite screen before. It looks as though it should would reasonably well provided that the stove doesn't get so close that something melts. My suspicion though is that it may be inconvenient. It looks as though it would take some time to, in effect, pitch the screen, much as one would pitch a tent. The nice thing about something like an MSR windscreen is that it can be emplaced very quickly.

 

for my uppright stoves I use a piece of tolling foil, I mostly leave an opening to check on canister temp, will post some pics on the weekend.

Tolling foil? Do you mean tooling foil? What dimensions are you using? How do you keep the foil from becoming all mangled? Or do you just replace it every so often?

On my MSR windscreen which I believe is 5.5"/14cm high, I wrap it around my canister (Xtreme) or a water bottle. However, my MSR windscreen only works on 110g canisters if I use it with an upright canister stove. If I use a 230g canister, the windscreen is a little too short, and if I use it on a 450g canister, it's absurdly short and utterly useless. I've been using the same MSR windscreen since 1987, and it's in very good condition considering. Wrapping it around the fuel bottle or a water bottle has made all the difference.

 

I have made my own fittings, I will take some photos and post them on the weekend.

I'm very curious to see your Powermax/Max refilling arragement.

 

I would not bother, though I have considered making my own propane-butane mix.

Agreed. It makes very little sense to fill a Max canister with 100% butane. The chief advantage of the Xtreme is its cold weather capability. Remove the propane, and you remove the cold weather capability. With 100% butane, instead of being able to operate down to about -10F/-23C, you now need your fuel to be at least 40F/5C. Using 100% butane turns a brilliant cold weather stove into a rather heavy fair-weather-only stove. :(

 

I have also considered making my own propane-butane mix. Relatively inexpensive propane and butane are both easily obtainable here in the US. I have purchased a Kovea adapter from an eBay seller in Korea that has a Coleman type propane tank connector on one end and a 7/16ths UNEF threaded connector on the other. It'd be a bit of a kludge, but I can use the Kovea propane-to-standard-threaded adapter to connect to my bayonet-connector-to-standard-threaded adapter and thus fill "long" butane cans with propane. I can then connect the "long" butane cans to a standard threaded canister with my bayonet-connector-to-standard-threaded adapter and transfer the propane to a standard threaded canister.

In this way I could make custom blends of propane and butane.

Of course the chief drawback to this would be safety. Would the long butane cans be safe to transfer propane to? The long butane cans, while designed for 100% n-butane are 100% steel. I suspect they'd be all right for temporary storage. Would the receiving standard canister be safe to store higher proportions of propane than originally came in the canister. Again, I suspect the receiving standard canister would be just fine with a higher proportion of propane since the remainder would be n-butane and the original mix was propane and isobutane.

And what would I get for all this work and potential risk? A canister of propane and n-butane which isn't an ideal mix for cold weather. I'd much rather have a propane isobutane mix even if the proportion of propane were lower than in the propane n-butane mix.

All that to say, I haven't gone very far down the path of refilling standard threaded canisters with propane.

I might do a little bit better with Powermax/Max canister since those are intended for relatively high proportions of propane, but I don't have a refiller for that type of canister nor do I feel confident in my ability to make one.

In the mean time, I do refill my standard threaded canisters with 100% n-butane which works fine so long as the fuel is kept above 40F/5C -- which is exactly the temperature range I tend to use an upright canister stove in anyway. If temps get below that, I start thinking about bringing a remote canister stove and using a isobutane propane mix in liquid feed mode. My refiller gives me a really cheap source of canister gas -- cheap enough (230g/$1.00) to be comparable to white gasoline (315g/$1.00).

Anyway, enough rambling from me.

HJ

July 29, 2014
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