Mini Trangia performance + my first post here

[David M]

This is my first post here so please be nice

I have until recently been out of bushwalking for a very long time but am now returning and buying new equipment as I no longer wish to carry 22kg loads. I want to be lightweight but not fanatical and still want to have some comforts.

I intend to soon go on an organised snow walk (Feathertop) and so I thought I would test my Mini Trangia to assess its performance and fuel consumption at one task it may need to perform and that is to melt snow if tank water at the hut or other liquid water is unavailable. I thought the result might be of interest to others.

I know there are huge debates about methylated spirits stoves vs gas but for shorter trips I believe meths is lighter than gas although I know that meths is slower...

I filled the Trangia bowl to capacity with water (800mls) and put it in the freezer overnight so the ice would have been at -18 C. I then put 50 mls of meths in the burner and proceeded to thaw the ice. The ice was melted and the water was bought to a vigourous boil within 24.5 minutes and the fuel was not consumed until 28.5 minutes had elapsed.

Melting solid ice is a much more severe test than melting porous snow so this is a fair test of theTrangia's capacity to melt frozen water. It was however done indoors so there was no wind which may affect the results.

I hope people don't mind me asking lots of questions here, and I hope to make many contributions of my own.

Regards,

David

[Strider]

Welcome David!

That's actually not bad going, considering the Trangia takes the best part of 10 mins to bring a similar quantity of water to the boil from room temperature.

[Tassiedevil]

Hi David,
Freshwater freezes at 0 C, so putting in a freezer at -18 C won't make it any colder. With porous snow it has air it which acts as insulation so it requires more energy and time to melt. To assist in speeding up the process add a little water, this will turn to steam causing the snow to become liquid faster which in turn then can boil.

[South_Aussie_Hiker]

Freshwater freezes at 0 C, so putting in a freezer at -18 C won't make it any colder.

Sorry, disagree.

It was however done indoors so there was no wind which may affect the results.

Absolutely. Even in very light winds, my cooking times go up about 50%.

[sthughes]

Interesting info. Yeah wind makes an enormous difference, especially so to a mini-trangia.

[Miyata610]

Ice out of a -18° freezer will be -18°.

[matagi]

Hi David,
Freshwater freezes at 0 C, so putting in a freezer at -18 C won't make it any colder. With porous snow it has air it which acts as insulation so it requires more energy and time to melt. To assist in speeding up the process add a little water, this will turn to steam causing the snow to become liquid faster which in turn then can boil.

Ummm ....... what?

Water freezes at 0 C certainly, but putting it in a -18 freezer will take the temperature of the ice to -18.

[Miyata610]

The confusion may be that liquid water stays between 0° and 100° at standard pressure, but as a solid it can go down to absolute zero. Near enough anyway.

[Strider]

Ice out of a -18° freezer will be -18°.

Correct. Though unless the OP has access to a -18C freezer ($$$$), I highly doubt the sample used was -18C.

[David M]

Ice out of a -18° freezer will be -18°.

Correct. Though unless the OP has access to a -18C freezer ($$$$), I highly doubt the sample used was -18C.

The ice was indeed at -18C out of my freezer.

Also, to the other person that correctly noted that ice freezes at 0C, for ice that is at a lower temperature than this it still requires extra energy to bring it to 0C. So ice at -18C requires more energy to bring the water to a boil than ice at 0C.

[sthughes]

Well just for fun I just tried this on my Kovea Supalite. Same amount of water frozen since mid yesterday, in pot of similar shape to trangia etc. I started with an almost empty 100g canister, the flame dwindled down and went out at about 2:30 and I changed to a new canister. At about 10 minutes the last ice disappeared and at 11:45 it was boiling rapidly enough to overflow badly enough to extinguish the stove (still at full throttle). That time includes around 20 seconds of no heat application while I moved the (still very hot - ouch!) stove to the new canister. Room temp was 9.4 degrees. Used 21g of gas from the new canister and I'd say about 5 from the old.

[clarence]

I'm assuming everyone is referring to the trangia 28T model.

I used one for years when I was a poor student. Even used it on a 4 week trip on Alpine Walking Track.

Wind is the biggest problem with the mini trangia. I used a foil surround (not unlike the MSR surround) and this gave a very marked improvement in cooking times and performance. It worked fairly well unless the wind was very strong.

The only problem then is it causes a huge amount of heat gain in the burner holder unit. The result is that the meths can boil and vapourise in the brass holder and the stove can get a bit out of control. I used to add a few drops of water to the meths to slow it down a bit.

The other problem on snow is the heat flow from the burner holder into the snow, potentially causing it to sink down by melting a hole in the snow.

The full sized trangias have more clever design put into them than most would realise. The elaborate burner holder and circular shield does several things. 1) Stops fuel holder heating up too much as it dissipates heat out through the holey flat surround (this would then presumably rise and heat the food anyway) 2) provides wind guard to direct heat up and around the pan 3) By doing what is mentioned in (1) it stops the support heating up too much and sinking into snow if there is any present.

I never found the 28T ideal in high altitude situations or snow. I swear by an MSR whisperlite for such applications. However, for a shorter weekend trip and low altitude stuff they will work pretty well (as I said I used one for a four week trip and we ate hot food every night).

Over extended walks I found 1L of metho would last for a week, cooking an evening meal for 2 people and occassionally a breakfast or cup of tea.

With an MSR you will find the fuel requirements would be about 60% of this. Note that meths is heavier per litre than petrol/shellite too.

I agree that frozen water can go below zero degrees. The energy used to melt ice into water is in roughly the same vicinity as raising it from zero to boiling, so always try to find water rather than ice. My understanding is that melting snow is actually more difficult as the energy must be put in to breaking the crystal structure of snow. This requires more energy that just melting frozen water.

Also be aware that as altitude increases and impurities are put into the water (impurities being the food, soup, milk etc) that performance relative to pure water at sea level will decrease.

Clarence

[jacko1956]

"Room temp was 9.4 degrees"
Ye gods son! Turn the heater on!!


Re OP.
I'm very happy with meth stove but I'll stick with my Caldera Cone over the Trangia.