Complete iso-butane cook kit for less than 8 ounces (including fuel)

[Casey Bowden]

First, thanks to John K for discovering the 1 oz Falcon air horn canister and Jan Rezac for sharing his file for the 3D printed stand for the canister.

I used my cook kit in Yosemite this October. Elevation was from 4k to 10k and temps were from 70’s F to below freezing. Cooked 3 dinners and 3 hot chocolates. Each boil was 8 oz. Started with 28 grams (1 oz) of butane and had 9 grams left when I got home, so average fuel use per 8 oz boil was 19 g/6 = 3.2 grams fuel per 8 oz water. I don’t normally have hot drinks when backpacking but did this time to test the setup. I can’t believe it could cook six dinners! Weights for all parts of the kit are shown, in grams, in the last photo.

NOTE 1: I never brought my water to a rolling boil. Made water hot enough to kill the critters and cook dinner (my version of Skurka’s rice and beans). Cooking consisted of adding my rice/bean mix to the water, turning the stove off, then letting it sit, lidded, with a cozy, for 10 minutes.

NOTE 2: The DIY windscreen I use restricts the flow of exhaust gases and requires that you use the BRS stove on a low setting.

 

[Jerry Adams]

I like how you wrote the empty and full weight on the side of he canister.  Looks like you wrote on masking tape.  You could save the weight of the masking tape and write directly on container.  (That’s a joke).

Your windscreen is similar to mine.  I have found that to work pretty good.

When I did like you, the windscreen fell off.  Has yours ever done that?  I put a piece of #18 galvanized wire on the outside compressing it to the pot to fix that.

[Casey Bowden]

Jerry, your DIY windscreen (from many years ago) was the inspiration for mine. And my version doesn’t fall off.

[Jerry Adams]

great!  I like it when one person modifies another person’s idea.

[David Thomas]

Very nice!  I see the pot handle is located away from the “chimneys” of the windshield – to keep it cool, I presume.

3.2 grams of butane to boil 8 ounces of (50F) water is a 53% efficiency (from gross heating value, 58% using net / non-condensing heat value) which is excellent.  Standard pots on standard burners are 30-35% efficient.  I suspect the “chimneys” in addition to holding the hottest air closer to the pot, also create more turbulence which is always your friend during heat transfer.  I got some aluminum BBs and JB-welded them to a pot for a bit of heat-exchange-fin effect but mostly for the turbulence and it worked well (I could mail you some of the BBs).  And you’d only need them on the pot inside those air passages.

[David Thomas]

With that tiny canister tank diameter and decently thick walls (I’ve fondled them and refilled them with various fuels), I have no hesitation in filling it with 100% propane.  Of course that gives you better cold-weather performance (handy in such a low-mass canister that will evaporatively cool quickly) and is basically free if bought in bulk in BBQ tanks.

But liquid propane is 79% the density of liquid butane while their BTUs/pound only favor propane by 2%, so with the same headspace, propane gives you 81% of the BTUs per volume.

[David Thomas]

Jerry:  “You could save the weight of the masking tape”

Or go whole hog like the airlines did during the 1970s fuel crises and strip all the paint off the metal as well.

Then acid-dip the tank to thin the walls, like stock-car racers do to the car body.

[Keith T]

Awesome! I’m curious about your parts:

Which pot is that?

What kind of tape is on the handle?

Where did you get the silicone ring to go around the lip?

Thanks!

[Jerry Adams]

” also create more turbulence which is always your friend during heat transfer.”

I wonder what you could design to increase turbulence.

Maybe a vortex burner like BRS3000 and Roger would help

maybe a metal strip somewhere

[David Thomas]

Jerry: I was thinking of the aluminum BBs, but I’ve also used the sticky metallic duct tape (made for actual use on actual ducts) to make fins that are 25 degrees to the air flow as is done with vortex generators on the top surface of airplane wings and that seems to work.  Spot-welded solid metal fins would be even better, but the duct tape lasted pretty well.

[Jerry Adams]

“I have no hesitation in filling it with 100% propane”

as discussed in some previous thread

as long as you don’t let the canister go above 72 F or something – I forget the exact number

propane at 72 F (?) will have the same pressure as butane at 120 F, the highest allowed temperature for butane

[DAN-Y]

[John K]

I like the evolution of the different ideas coming together. I’ve optimized my alcohol setup but never got all the way there with my butane setup. I’m inspired to try and lock that one down. Fun stuff!

[Glen L]

<p style=”text-align: right;”>Very interesting</p>
been doing a few more things with research on my setup too. If what happened on Monday is actually true it will be super efficient. Got the tea way too hot to drink with about 3 g of  isopro for half a liter of water but like you don’t need to take it all the way to a boil. The experiment continues.

[Jerry Adams]

good idea dan-y

[Casey Bowden]

Hi Keith,

The pot is a stainless steel mug I picked up at a small store in Oakland’s Chinatown many years ago for a few bucks. 80 grams and holds 650 mL when filled to the brim. Diameter is the same as Jetboil pots.

Tape on the handle is silicone hat has no adhesive, but sticks to itself. With the windscreen shown I probably don’t need the tape but earlier windscreen iterations vented the exhaust gas right onto the handle and made it too hot to use.

Silicone ring around the lip is a “LiveStrong” bracelet. Not sure why I had that.

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