Hiking stoves

30 Nov 2011 08:07 #5047 by Serious tribe
Replied by Serious tribe on topic Re: Hiking stoves
@intrepid - computer programmer and scientist. Yikes!

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30 Nov 2011 08:21 #5048 by intrepid
Replied by intrepid on topic Re: Hiking stoves
Chem and Applied Chem major, back in the day ;)

Take nothing but litter, leave nothing but a cleaner Drakensberg.

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30 Nov 2011 09:04 #5051 by tiska
Replied by tiska on topic Re: Hiking stoves
Nice clarity on the chemistry. I didn't expect to learn this stuff on a stoves thread!

I reckon there is also a bit of physics involved though. When gas is released from the gas cyclinder, the pressure drops in the cylinder and this is matched by a temperature drop. You might have noticed this when picking up a gas cylinder after boiling some water - the cylinder is normally v.cold with condensation on the outside. (dh=cpdt-pdv, in this case dh=0 as there is no external heating, so cpdt=pdv, meaning that heat (left hand side) relates directly to pressure (right hand side). If one drops, so does the other).

So it is necessarily true that using one of these gas cylinders drops the temperature in the cylinder and makes the burn less efficient because of the chemistry which has already been explained.

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01 Dec 2011 04:39 - 01 Dec 2011 04:41 #5069 by Serious tribe
Replied by Serious tribe on topic Re: Hiking stoves
Oh no....this is becoming a geek thread! ;)

We have had this situation when the butane remained behind because it got so cold and we wrongly assumed that it was a dud cylinder. (Still using camping gaz system) So what I thought one could do, not that i have all this chemistry knowledge, is pipe or force some of the heat from the burn down to the area of the cylinder, or as I have just read, get an inverted system. Here is a link that i found that discusses different options and some home adaptations to converting an upright system into an inverted system. Just beware as the author says because it can become quite volatile!

www.bushwalking.org.au/FAQ/FAQ_GasStoves.htm#Powermax
Last edit: 01 Dec 2011 04:41 by Serious tribe.

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01 Dec 2011 08:26 - 01 Dec 2011 08:27 #5072 by tonymarshall
Replied by tonymarshall on topic Re: Hiking stoves
Thanks ST, informative article. :thumbsup:

I also still use the camping gaz stove, and have shared your experience, although not to the extent that the stove died, in colder conditions. I began to think I should have heeded all the warnings about gas at altitude and in cold conditions etc, and should dig out my liquid fuel stove, when somebody tipped me off to keep the cylinder warm. B) Now I better understand the chemistry and physics behind this! :laugh:
Last edit: 01 Dec 2011 08:27 by tonymarshall.

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01 Dec 2011 21:54 #5077 by Serious tribe
Replied by Serious tribe on topic Re: Hiking stoves
No problem. The info was all new to me, as I have never really looked into the chemistry of it, or how these things actually work. Were it not for a couple of the comments on this thread, I would still not be any the wiser about the physics and chemistry of the humble burner.

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02 Dec 2011 05:31 #5079 by Geordie
Replied by Geordie on topic Re: Hiking stoves
I would strongly advise against playing around with modifying to an inverted gas system. The valve is just not made for liquid and problems may only arise in the long-term. Read, high up on the mountain in the freezing cold, watching your tent and kit burn down while attending to your serious burn wounds.
I must say, these ultra light sites are a constant source of:
Useful hints and tips, Mild amusement, shock and horror, head shaking.
My personal approach to the mountain is one of respect, she expects you to be well prepared and she punishes those who are not. Imagine being camped at 3000m and depending on a stove made from an old coke tin and some folded tinfoil ( But it weighs nothing mate), and if you are that cheap, don't tell me that you invested in a descent fuel container, so, methylated spirits soaked dog biscuits anyone. Kind of negates the need for a stove.

There we go ST, from geek to preacher to BOF (No, not boffin, rather Boring Old Fart)

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02 Dec 2011 09:04 - 02 Dec 2011 09:04 #5083 by Serious tribe
Replied by Serious tribe on topic Re: Hiking stoves
@geordie - nothing wrong with being a safe boring old fart ;) . I would agree 150%, I would far rather buy a properly designed system that has gone through all the research than a jury rigged system. With my cameras, I am prepared to do a bit of my own tinkering with certain things, but with fire producing apparatus I will leave it to the experts, especially when in a tent at 3000m. I think that a correctly engineered and commercially available inverted system certainly makes sense for high altitude and cold conditions.

I think with everything on the internet and on this current article, there is information that we can use to educate ourselves and there is info that is interesting but does not have to be implemented. I certainly was not going to take the time and effort to copy and paste only the bits that were information based.
Last edit: 02 Dec 2011 09:04 by Serious tribe.

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02 Dec 2011 09:16 - 02 Dec 2011 09:34 #5084 by tiska
Replied by tiska on topic Re: Hiking stoves
Not a Berg story this one, but the thread did remind me. We did a trip to SW Egypt (Jebel Uweinat on the Libya, Sudan, Egypt triple point) a few years ago. Egyptian red tape meant we used Egyptian cars which always come with their own drivers. All 3 cars were hard to start in the frosty mornings - in fact only one would fire up reliably off its own battery. And to get that one going, there was a morning routine which began by putting the gas cylinder on the gas burner and lighting the gas burner (flames would then heat the cylinder) - presumably to take care of the chem and physics we've discussed. After about 5 minutes of cooking the gas cylinder, the burner would go under the sump of vehicle nr 1 to heat the sump oil. Precious water was used every day to douse the burning oil leaks. Jebel Uweinat is quite remote, each car had 600L of fuel in it. I used to view all this from a 'safe' distance of about 1km, with a bag of water and a satellite phone in case the chem/phys got overcooked as it were.

Climbing Jebel Uweinat wasn't the hardest part of that trip!
Last edit: 02 Dec 2011 09:34 by tiska.

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02 Dec 2011 12:06 #5085 by Geordie
Replied by Geordie on topic Re: Hiking stoves
Viva free access to information viva, those sites I mentioned have taught me a lot and dare I say it, helped to shave off some of those grams.
They do insist however, that everything taken along, must have a dual or multi purpose which raises the question. What else do I do with my trusty old jet boil other than, well, boil ,I guess. Will spend the weekend pondering that one.

Enjoy.

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