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Alan Dixon
(alandixon) - MLife

Locale: Mid-Atlantic
Re: Chad; Alcohol for a short trip? Caldera Cone on 08/02/2007 09:54:50 MDT Print View

I don't think I agree with your numbers Chad. (SEE CHART BELOW)

With my weights, the Alcohol systems wins up to 17 pints boiled and much of the time over the Standard Canister (Snowpeak) for the rest of the curve. Both systems remain lighter than the Jetboil system all the way up to 50+ pints boiled.

It seems that you may have the JetBoil system weight too low (you have it around 520 g while I calculate around 630 g with a 3.5 oz fuel canister). It also seems that you may have the Alcohol and Standard Canister (Snowpeak) system weights too high. (I have included my weight calculations for the various systems below the chart.)

Stover Performance Curves

Note that the steps in the performance curves come from changing fuel storage as the pints boiled increase above the capacity of a container.

Alcohol (TD Caldera)
2.1 Caldera stove + cone BPL 1.1L Pot
3.1 BPL 1.1 L titanium pot w lid
178.6 1.1 Alcohol cont 8 fl oz + meas cup 12g/pt tot 15.5 pt boiled
6.3

15.2 Jetboil
7.0 Fuel canister 3.5 oz (boil 20 pts)
629 22.2 oz

15.2 Jetboil
8.0 Fuel canister 4oz (boil 24 pts)
658 23.2 oz

15.2 Jetboil
12.0 Fuel canister 8oz (boil 47 pts)
771 27.2 oz

Canister
3.0 Coleman F1 stove
3.1 1.1 L titanium pot w lid
0.6 Windscreen
388 7.0 Fuel Canister (3.5oz full) 16 pts boiled
13.7

Canister
3.0 Coleman F1 stove
3.1 1.1 L titanium pot w lid
0.6 Windscreen
403 7.5 Fuel Canister (4oz full) 18 pts boiled
14.2

Canister
3.0 Coleman F1 stove
3.1 1.1 L titanium pot w lid
0.6 Windscreen
530 12.0 Fuel Canister (8oz full) 36 pts boiled
18.7

Canister
3.0 Coleman F1 stove
3.1 1.1 L titanium pot w lid
0.6 Windscreen
7.0 Fuel Canister (3.5oz full)
729 12.0 Fuel Canister (8oz full) 52 pts boiled
25.7

Chad Miller
(chadnsc)

Locale: Duluth, Minnesota
alchohol stoves on 08/02/2007 10:10:31 MDT Print View

Alan, I didn't post any numbers or graphs nor did I discuss anything about fuel efficiency. Next time please use your great attention to detail to check who you’re attributing posts to.

Richard Matthews
(food) - F

Locale: Colorado Rockies
Slope? on 08/02/2007 10:55:36 MDT Print View

Alan,

I appreciate your analysis. However, I do not understand how any of the lines could be level. I agree that the canisters use less fuel per unit boiled, but they do use fuel.

I understand the mini stairs on the Caldera when additional storage containers are added. With resupply I carry the 16 oz. dispenser from Brasslite (2.3 oz.) because it will hold a full HEET bottle. When I carry all the alcohol from the start I carry the extra in a PET bottle. The 8 oz. size weighs only .7 oz. The PET bottles can crushed when empty.

Thank you for the analysis.

Alan Dixon
(alandixon) - MLife

Locale: Mid-Atlantic
Re: Slope? on 08/02/2007 11:06:52 MDT Print View

>However, I do not understand how any of the lines could be level.

The weight listed is the starting weight, so it does not go down over time. Therefore, the lines are level since you can only get canisters in specific weights. In contrast you can bring any amount of fuel you want for an alcohol stove. This leads to varying starting weights.

Alan Dixon
(alandixon) - MLife

Locale: Mid-Atlantic
Re: alchohol stoves on 08/02/2007 11:09:05 MDT Print View

My bad. Apologies!

It should have been Brett.

Brett .
(Brett1234) - F

Locale: CA
Kathleen, Alan, answers on 08/02/2007 11:30:39 MDT Print View

Kathleen, yes, you are reading my chart correctly(although I made a numerical error and just updated the chart). The Snowpeak line would cross the alcohol line if I could get enough burns from a 100gram canister. But at 12 g/burn I can't.
Alan, thank you for noticing my numbers were low; they were for starting weight including a dry canister using algebra.. I actually placed the setups on the scale with a full canister and corrected the numbers. The alcohol setup includes the weight of the same Trek900 pot and caldera used in the canister setup. These are both about the same capacity as the Jetboil. To neglect the pot in these two setups would make the Jetboil seem even heavier. As it is, the canister or alcohol are lighter for short trips.
I'd like to update the chart to calculate total gram-days. Although as Ben says, convenience is also important; If Im rushing out the door to the crag or something I usually grab the Jetboil setup.

Question please? I understand the big steps in your graph, having to carry another canister, but what accounts for the small steps?

Edited by Brett1234 on 08/02/2007 11:47:38 MDT.

Daniel Goldenberg
(dag4643)

Locale: Pacific Northwet
Re: Re: Slope? on 08/02/2007 11:32:06 MDT Print View

"The weight listed is the starting weight, so it does not go down over time. Therefore, the lines are level since you can only get canisters in specific weights. In contrast you can bring any amount of fuel you want for an alcohol stove. This leads to varying starting weights."

Of course you can actually (assuming you have some partially used canisters) start with a less than full canister if you won't be out that long. This would reduce the starting weight of the canister setup

The starting weight is an interesting analysis. Even more interesting is the total system weight over time. I've plotted some graphs for various systems (alchohol/esbit/canister/woodburning) and the results are interesting. For example, an alcohol systems liability (high fuel weight/low fuel efficiency) becomes an asset over time because the fuel is used up at a higher rate. It will generally be the lightest towards the end of a trip. A bushbuddy system will be one of the lightest towards the beginning of a trip but will be heavier towards the end.

For the trips I tend to take (shorter durations) the weight difference between most of these sytems is not that much, so ultimately it comes down to personal choice/style, fiddle factor, etc

Alan Dixon
(alandixon) - MLife

Locale: Mid-Atlantic
Average Carry Weights for Stove Systems (for pints boiled) on 08/02/2007 14:39:44 MDT Print View

> Even more interesting is the total system weight over time

Here are the Average Carry Weight curves per pint of fuel boiled (which is essentially a time sequence assuming you boil a fairly constant amount per day).

Average Curves

Richard Matthews
(food) - F

Locale: Colorado Rockies
WARNING!!!!! on 08/02/2007 15:04:22 MDT Print View

BPL does NOT advise boiling stove fuel.

Your charts confirm my experience. I boil 3 pints per night and like to carry a little alcohol in reserve. Without the Caldera Cone I switched from alcohol to canister after 2 nights. With the Caldera I switch to a canister after 4 nights because the convenience of the canister is worth a little weight.

Good graph, thank you.

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: alchohol stoves on 08/02/2007 17:54:26 MDT Print View

Hi Brett,

A great forum debate. I hope to contribute when I have a bit more time.

“The Snowpeak line would cross the alcohol line if I could get enough burns from a 100gram canister. But at 12 g/burn I can't. “

I gather that this is for 500ml. 12 g canister gas is a lot of fuel to boil 500 ml water, my testing on my std upright canister stoves uses 5-7g of fuel. My JB uses 4-5g.

Tony