TBH, if I'm going any distance the stove might be left behind in favor of collecting wood for a real fire on site.
Stove Fuels
- Thread starter gliderrider
- Start date
TBH, if I'm going any distance the stove might be left behind in favor of collecting wood for a real fire on site.
What stuff? All the under blankets, wooly blankets etc? Very doubtful, but people (including me) carried paraffin/petrol stoves with no problem hill walking four season for many years and even if I was hiking now on a trip for two or more I'd pack an Optimus 111, did until I had to stop walking back around 2008; twas no big deal.
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Your choice obviously, but it wouldn't be mine. No matter which way you spin it, the numbers just dont add up.
In your opinion, while they may not suit you, the numbers may suit others. Your view on this subjective matter is just that, your view and not a universal one Martyn
"Every gram counts"
SO we should count then:
for a weekend:
Optimus crux plus 220 g canister full - 490 grams
SVEA 123 with 130 ml fuel inside - 540 grams
Super cat plus 130 ml alcohol - 120 grams
So the SVEA is a little heavier than the Crux, not 500 grams and if weight is the criterion, then the alcohol is the "best" fuel.
SO we should count then:
for a weekend:
Optimus crux plus 220 g canister full - 490 grams
SVEA 123 with 130 ml fuel inside - 540 grams
Super cat plus 130 ml alcohol - 120 grams
So the SVEA is a little heavier than the Crux, not 500 grams and if weight is the criterion, then the alcohol is the "best" fuel.
I do 'backpack' ( and occasionally canoe) a fair distance more often than not with some kids in tow and acting as the part 'mule'..I'm happy to go with the following...
Optimus 00
Optimus Explorer...
Optimus Crux...
ESBIT / Hexi.
Primus 71....
I don't really get that caught up in the pack weight thing TBH I generally take what I fancy using on the given trip or what makes the Most 'sense' to use...If I have a couple of criteria is that a stove is suitable for the task and is quiet in operation. I am not a fan of roarer burners tbh especially in close confines....
Really it makes as much 'sense' to take a 123 or a 111 as it does a über light Meths's stove made from TI. If you're happy carting it then you're happy....
Optimus Explorer...
Optimus Crux...
ESBIT / Hexi.
Primus 71....
I don't really get that caught up in the pack weight thing TBH I generally take what I fancy using on the given trip or what makes the Most 'sense' to use...If I have a couple of criteria is that a stove is suitable for the task and is quiet in operation. I am not a fan of roarer burners tbh especially in close confines....
Really it makes as much 'sense' to take a 123 or a 111 as it does a über light Meths's stove made from TI. If you're happy carting it then you're happy....
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In your opinion, while they may not suit you, the numbers may suit others. Your view on this subjective matter is just that, your view and not a universal one Martyn
Pot - Kettle - Black!
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Is that a thermally efficient aluminum but traditional kettle or an uber lightweight TI kettle??
Johnboy and I were discussing doing a comparison test with these stoves. There are problems with your numbers. First, how efficient are the stoves? Maybe 20% - 40%. Are all three stoves as efficient as one another? Secondly, why carry 220g of gas for a weekend? Unless you are brewing up continually, one 100g can should be enough. Thirdly, how many g of gas is equal to how many ml of petrol - not in terms of volume or weight, but in terms of calorific value of the fuel?
Petrol/Paraffin has a typical specific calorific value of 44-48 MJ/kg
LPG has a typical specific calorific value of 46 MJ/kg
Methanol has a typical specific calorific value of 23 MJ/kg
So while petrol and lpg have pretty similar calorific values, you need nearly twice as much methanol to have the same heating potential. Remember also that methanol has a much lower specific gravity than water at about .79 or 79%. So 100ml of methanol weighs 79g. Petrol has about the same specific gravity.
This means to have the same potential calorific value of 100g of LPG, you need 127mls (100g) of petrol and 254mls (200g) of methanol.
So, to go back to your numbers, the equivalent in terms of potential calorific energy of a SVEA 123 with 130mls of petrol inside, is 100g can of gas + stove.
SVEA123 + 130 mls of fuel = 540g (your numbers)
Optimus crux + 100g can = 280g.
That's a saving of over half a pound.
This is obviously without considering stove efficiency - or how many of those potential calories actually get converted to heat by the stove. This is obviously very important as a stove that is 40% efficient, needs half the fuel of a stove that is 20% efficient. It's impossible to comment on the relative efficiency of the stoves mentioned, without doing timed boil tests and weighing the fuel before and after, so you have an actual figure to show how much fuel is used to boil X amount of water.
You are right, alcohol stoves are lighter, but only for the first day or 2 (assuming a need to boil 1 to 1.5 litres per day) and then only if you calculate and carry the exact amount of fuel you need. If you are in the habit of throwing in a litre of meths just in case, all advantage is lost. The alcohol stove advantage comes from a very low stove weight, but after boiling about 3 litres, the advantage is lost out to lpg/petrol with it's much higher calorific value.
After a couple of days, gas becomes the lightest option and then after about 3 weeks, the advantage of bulk carry of petrol/paraffin offsets the disadvantage of gas cannister weight and the heavier stove [and/or pump] and petrol becomes the lightest option.
There are obviously tons of other factors, such as altitude, pumps or lack of, priming fuels or pastes, cost, personal preference etc, but if you are comparing fuel types as an academic discussion, that is how the numbers pan out - and it's not subjective.
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Not on an alcohol stove they don't get 'that' hot.....I'm not sure - wouldn't the Ti kettle go blue?
On these trips your going on, are you lugging water with you or are you taking it from on the trail? Having to actually boil water to remove nasties would up the fuel needed quite a bit I would have thought. Seeing as though you will be filtering the water of crud either way, boiling or chemical sterilizing, would not using some form of steri-tab reduce the fuel needs a lot as you no longer have to heat to 100 degrees and can have just hot drinks/food against scalding ones?
Steve.
Steve.
Over 70c, but to make sure the water is heated through bring up to a boil and job is done.
Martyn, just checking your figures, Gas or petrol would be better than meths etc if you were on a trip of upto 2 weeks, or if you were being re supplied.
Yeah, it depends on the weight of your stove obviously - and meths bottle, pot stand and windshield (essential for meths). I was working on a trangia burner.
A full 100g can of optimus gas weighs 200g, which has the same calorific value of 250mls/200g of meths, so it's always going to be a close thing. The only way meths can "win" is if the combined weight of the stove, alcohol fuel bottle, pot stand and windhield, is less than 87g (the weight of the crux), or if your fuel requirements are less than the minimum 100g cannister weight.
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As Martyn points out the real advantage of an unpressurized Meths's burner is that they can be really light weight either made from an old pop tin or something knocked up out of TI which you have to sell a kidney to buy.
The relatively low calorific value of the fuel means you need more of it... So if your heading out for a couple of days and you are 'only' using the stove say for breakfast and an evening meal then it sort of makes sense if you fuel discipline is really good and nothing unforeseen happens... If you like to brew up frequently and cook expansive meals then you'll need to carry more fuel which means more weight. If you're going for an unpressurized Meths's burner then you need to get one that is really really efficient a turning potential heat energy in the fuel to actual heat energy.. When you find one let me know...
As mentioned there are simply heaps of other factors to consider from efficiency to wind resistance to useability of the stove in question... For 99.9% of the time in my rose tinted recollection of conditions prevailing in the UK, a simple gas stove running on en417 type cannisters makes a lot of sense..
However Meths's does have that 'man make fire' element to it and gas stoves are relatively boring in comparison...
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I have a Chinese Crux clone which is 90% TI in construction and it weighs something like 40g - 50g and works as well as the Crux....So what's that 250g for a stove and 100g can with a lot of potential heat energy....
Can you be a bit more specific on this point John? Do you have say a boil time per amount of fuel per amount of water as a measure of efficiency your looking for?
Steve.
Don't confuse efficiency with effectiveness..
Say I have 100g of Meths's with a potential heat energy output of 1 mj ( not real figures but generalized for the sake of conversation)
If my stove burns all of the 100g of Meths's exceptionally cleanly then i'll release that 1mj but all stoves do not burn fuel that cleanly you'll get some partially combusted fuel which will show up as soot or Co or incandescence in the flame..
Partially combusted fuel has not released its full energy potential so that potential 1mj is now less...
What you can do if you have the correct apparatus is collect all of soot and other stuff and weigh that ( generally you weigh filter weight prior and after) That would give you an indication of how efficient the bare burner is.
But putting a pot onto the burner or stove might impinge the flame and make combustion worse so you get more soot production and the efficiency of the stove is lowered further...
What I do know and you could possibly observe is that Meths's when it burns in an un pressurized burner often has incandescence in the flame ( yellowing ) that is more often than not caused by soot and other particles in the flame..
That soot is partially combusted fuel... If you get an unpressurized Meths's burner that does not produce yellowing on the flame and leaves soot on the base of your pots then you are onto an efficient burner.. How effective that burner is might be a different story...
So if you are starting out with a burner that is not converting 100% potential fuel energy into actual useable energy then any other factors such as conductivity of the pot, Standoff from the burner etc are only going to make the effectiveness of the stove worse..
HTH
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