cold weather performance upright canister

[Roger Caffin]

Very neat! I like it.

Cheers

[Stuart R]

Looks like a a neat trick, but water expands as it freezes…

"1gr if 32f liquid water will give up enough energy to boil 1gr of isobutane as the water freezes."

I reckon 1g of water->ice gives up enough heat to evaporate 0.86g of butane, so perhaps you can burn 30-40g of butane before ice breaks the seal? Only one way to find out.

[James Klein]

Last night after posting I put the canister in the freezer and the seal never broke. Of course maybe it froze around the diameter first where as when running a stove on high it might be more likely to freeze in the canister bowl.

I mainly did it to see how hard it would be to remove the ice chunk. I got the ice out without too much effort but I don't know how much my warm house helped….still need to give it a go when the temps drop around here.

[Jerry Adams]

Yeah, neat idea!

One problem is, if it freezes you won't be able to get it off.

Anyway, ask and I shall do my best to obey : )

I couldn't find the right size lid so I got a container a little bit bigger – 0.5 oz

I put 100g (~3 oz) water in it. it started at 40 F but it was rapidly cooling from ambient air. 33 F after I heated the water in the pot for tea.

19 F and dead calm

Took 5 minutes to heat 15.6 oz of water from 10 to 95 C. 6 g of isobutane consumed. I'm drinking the tea as I write. I splashed up water onto the side of the canister a little.

I think a bigger container and more water helps. It get's cold from ambient air more than vaporizing the butane.

The water was not deep enough to contact the concave bottom hardly at all, so your technique might work a little better, but being able to splash water on the sides is good. I just used one finger and dribbled a little water. Also, there'de be less surface area to lose heat to ambient.

Anyway, in summary, I am underwhelmed by any of the copper/aluminum conduction techniques. I couldn't get the minimum temperature I could operate at reduced by very much, maybe reducing from 23 F to 16 F. And you have to experiment to get a configuration to work. Maybe a couple strips of aluminum and extend to the bottom of canister for more contact area. If this would work, it would be simpler than having to screw with water.

I think the container with water works much better. Maybe I'de use 4 ounces of water 1 inch deep. For each pot of water, I'de heat up 1 ounce more water than I needed, and put that in the container for the next pot.

And, maybe the best conclusion from all of this is to use inverted canister or white gas.

Uh oh – it's warming up – and it will be 10 years before the next stretch of cold weather like this in Portland, OR. Sunday morning I think it was below 10 F. Not quite an all time record (maybe 7 F?). And 3 mornings in a row below 20 F. I think I'll try walking across the swimming pool…

[James Klein]

One issue with a water bath that this try skirts is – the water in an open bath cools a fair amount extra from evaporative cooling…how much this works against you relative to the benefit of having more if the canister sidewall protected from cold air….? Idunno.

Hopefully I'll see some colder weather and give it a try.

[Mitch Chesney]

Use the warm piss from your nightly excretion as the canister water bath during morning cooking. Takes a while for ~98.6F water to drop below isobutane's vapour temperature. And you were going to through it out anyway. Just don't spill it in your tent :)

Or use a preheater coil properly seated on the canister, use thermal paste to enhance conductivity (http://www.newegg.com/Product/Product.aspx?Item=N82E16835100007).

[Roger Caffin]

> the water in an open bath cools a fair amount extra from evaporative cooling.
Well, true but not necessarily relevant.

I sometime put the canister in my (plastic, GSI) bowl and add water. As the bowl is only slightly larger than the canister, most of the water sits under the canister and can't evaporate. I start with just a little water in the bowl and add warm water from the pot by the spoonful. Rarely would I need to add more than 2 -3 spoonfuls before the water (enough for 2) is boiling.

Of course, if it is going to be cold all the time I will use an inverted canister stove anyhow. Given the very light weight of mine, there is not a lot of incentive to push an upright into cold weather.

Cheers

[Rick M]

del

[James Klein]

Roger, re: " true but not necessarily relavent"

I put ran my setup thru a freezer test to see how long it would take mine to freeze solid and then hoped to compare to equal amount in an open water bath. Used ~80gr of 60f water and placing in my 0f freezer…

1) using my trick water went a full 3 he's before freezing solid. It took about an hr for the first hint of ice to begin forming.

2) using the smallest tubberware bowl that will fit the 220g msr canister and not specifically inverting the canister to fit extra water in the bowl- just pressing down on the canister after filling.
The water went about 30min before any ice started. After about an hr the entire side wall was frozen with the rest of the water frozen water at 2hr30min.
The rate if freezing did seem to slow down somewhat after the side wall froze, blocking of the evopation path.

[James Klein]

One additional take away I have here is once the sidewall is frozen very little of the remaining liquid is in contact with the bottom of the canister. So even if you are going to use an open bath setup , I would recommend filling the canister bowl while upside down, the putting the bath container on and the inverting it all together.

This prevents floating canister syndrome rick points to above.

[Roger Caffin]

> the small canister can float when I took the pot off the flame
OOPS!
Worth noting. Use less water maybe? Really, you only have to have the water touching the rim by a few mm. The steel will conduct enough.

Cheers

[Roger Caffin]

> using my trick water went a full 3 he's before freezing solid. It took about an hr
> for the first hint of ice to begin forming.

Eh, not bad!

Cheers

[James Klein]

So I was able to give my plastic lid canister bath hack a go during a particularly cold morning in the mountains a couple of days back.

I was using a 110gram snowpeak 85/15 isobutane/propane blend that had 30% fuel remaining (practical operating limit of 15-20F). For breakfast I made 2 servings of eggs, bacon and gravy (a made biscuits using another stove). This required me to run this stove on low-med for probably 20-35mins (overall I burned ~25g fuel). The air temp during cooking was 7F. On purpose I used nearly frozen water for the canister bath.

Overall, this worked well. I never had to warm the canister. Heat output never seemed to decrease. After I finished eating I got around to removing the plastic lid and the water had frozen solid…was a slight pain to knock all of the ice out but only took a minute or so to accomplish.

You can just make out the black peanut lid below the canister…

[Roger Caffin]

Hi James

You know, if you had moved the canister just a shade closer to the stove, the water in the lid may not even have frozen. Thermal feedback!

Caution: monitor canister temperature with you finger. If you can touch it OK, you are fine.

Cheers

[Jerry Adams]

If there's significant thermal feedback, then you don't need water.

So, the trick is, to design the windscreen doing the opposite of what you recommend in the exploding canister article, and then only use it when it's really cold (and monitor temperature with your finger).

But, it would require a bunch of testing and different prototypes.

(or just buy inverted canister stove : )

[Roger Caffin]

Hi Jerry

> design the windscreen doing the opposite of what you recommend in the exploding canister article,
Well, to some degree, maybe so. But I (as a Staff member) have to be very careful about what I recommend.

I must admit, I have since given up using a radiation shield and never carry one. But that is partly because the stoves I now use throw the heat upwards a bit better and put the flame a bit further from the canister. But I am still very careful to monitor the temperature of the canister while the stove is lit.

Cheers

[James Klein]

Well the temp on my front porch tonite is 5f…so I decided to give this technique a further test.

I had a 227gr msr fuel canister with 40g fuel remaining. I let a couple of liters of water, the stove and fuel canister sit outside until the water began to ice over.

I used the ice water for the inside-the-bowl water bath. Filled nearly the entire bowl and installed a dannon yougurt lid.

I was able to boil 2 full liters of water and then run the stove for another 15 minutes- total burn time was over 42mins before using all of the fuel. There was still a little liquid water left so it could have run longer….seems like a winner.

[Ken Larson]

"I used the ice water for the inside-the-bowl water bath. Filled nearly the entire bowl and installed a dannon yougurt lid."

James….could you provide a picture of this as I cannot connect the "dannon yougurt lid" to the set up?

[James Klein]

Ken checkout my post on 12/08/2013 21:15:02 in this thread for instructions (with pics). Let Me know if you need addt details.

[Ken Larson]

Understand the concept and method you utilized. What I could not picture in my mind is the Dannon Yogurt lid (quart size I failed to visualize) as I thought they were small in diameter and would not fit on the bottom of the canister. Filing the entire "bowl" (bottom of the canister) and then installing the lid I understand.

[James Klein]

Ok I see.

Yeah the lid was from a quart size yogurt container. It is just larger than the msr canister.

Here is a pic of the two together:

[Jerry Adams]

Nice experiment, thanks for taking the time to document and post.

I hate experiments like putting a canister in an ice bath or the freezer because there's no way to relate. I like just operating the stove normally when it's a particular temperature.

Now I've got to find a lid with the right size.

I suppose I could take a canister to the store but I don't think they'de appreciate me trying on different lids. They would think I was contaminating them trying to poison someone : )

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