The Caldera Cone’s 12-10 Burner

Jim,
Yes, the 12-10 is a nice stove. Unlike the older Brasslite design it is modeled after, it lacks any adjustment around the air intakes. Easily rectified with a piece of a can and some notches to slow things down. Brasslite uses a single smaller sleeve silver soldered to the bottom, leaving about 1/4" all around the top as an air inlet. The 12-10 simply punches holes.

The air intakes are not really burner holes. They allow air into the combustion chamber. The somewhat additional length, between the lower holes and upper holes, allows the air to actually enter at a slightly increased velocity due to heating as it passes by the heated combustion chamber. Soo, it appears as a jetted intake…air in a fuel vapour region or fuel vapour in air…the same effect, visually.

I built several of these using JB weld to seal the bottom and side peices together. Within a couple inches, the taller they are, the more heat they generate for the same diameter combustion chamber. But, they also burn more fuel doing it. Time vs efficiency. Trail Designs did a good job with that sove though. It is really well balanced. You can do better with efficiency only at the expense of time heating.

James Marco wrote: > …the 12-10 is a nice stove.

Yes, and I don’t think I fully appreciated that until I tried to design my own. It’s not so easy to come up with something more efficient than a 12-10 that also works well and is reliable. Having wrestled with burner design for some time now, I really appreciate just how good the 12-10 burner is. A tad unconventional, but it works.

James Marco wrote: > Unlike the older Brasslite design it is modeled after, it lacks any adjustment around the air intakes. Easily rectified with a piece of a can and some notches to slow things down.

Interesting. I’ll have to try that. I imagine a sleeve made from an aluminum can with basically matching holes could be placed around the 12-10’s body. The sleeve could be rotated so that the holes match exactly for a full power burn or re-positioned to partially obstruct the holes for a reduced power burn. Interesting!

James Marco wrote: > You can do better with efficiency only at the expense of time heating.

Yes, that is the tradeoff.

HJ
Adventures in Stoving

So, how efficient is this stove? I know the variables are innumerable, but any ballpark figures?

Is this stove suitable for small diameter ti mugs? I have very good results with my Gram Weenie and Snow Peak 450.

Hi, Travis,

With regular denatured alcohol, I can boil two cups of cold creek water at 9,000+ feet with about 16ml of fuel. That’s pretty consistent.

Travis wrote: > Is this stove suitable for small diameter ti mugs?

Not so much, or at least not with a mug alone. The 12-10 stove is really meant to be used with a Caldera Cone. If you have a Caldera Cone windsreen/pot support that fits your particular mug, then, yes, absolutely.

HJ
Adventures in Stoving

16 oz boiled with 16 ml is pretty crazy!

I usually get 12-14 oz boiled from ~15ml of Everclear (plus a little priming fluid) on my Gram Weenie with a regular windscreen.

It’s tough to beat a Caldera Cone with a 12-10 burner inside. Believe me, I’ve tried.

HJ
Adventures in Stoving

HJ must know the trick.

Just now I tested using the 12-10 burner inside a titanium caldera cone. Room temp. Tap water. The narrow titanium pot holds 24 oz, and I used 16 oz of water in it.

For the first run, I used 22ml of S-L-X alcohol. It flamed out at 5:45, almost to a boil. I cooled everything down to normal and ran it again with 33ml of S-L-X. It boiled at 6:00 and flamed out around 7:00. So, it probably consumed around 25ml for the boil.

The 12-10 is very lightweight by itself, but it expects to have that cone around it to support the pot. Even though the titanium caldera cone doesn't weigh much, it is a bit bulky, even when rolled up. Aluminum foil doesn't make such a good windscreen, but it folds down tiny and weighs almost nothing.

As I recall, 22ml=1.5 Tbsp.

–B.G.–

Bob,

I’m also using SLX for those numbers I’m mentioning. I put in just slightly more than 1/2 fl. oz, which comes out to about 16ml, maybe 17ml, on the little measuring cups that you can see in the below photo. I was up at 9000+ feet in a saddle near Jepson Peak in Southern California. Actually, I think that saddle may be above 10,000′ come to think of it. I liste the elevation deliberately since it will depress the boiling point.

HJ
Adventures in Stoving

"Interesting. I'll have to try that. I imagine a sleeve made from an aluminum can with basically matching holes could be placed around the 12-10's body. The sleeve could be rotated so that the holes match exactly for a full power burn or re-positioned to partially obstruct the holes for a reduced power burn. Interesting!"

Yeah, well, you will find that the 12-10 holes are mis-indexed a bit. I thought I had screwed up, but further rotation found all the holes open in one position, and most of them, not all, open in another.

Anyway the controll also increases burn time from about 5-6 minutes or so to about 9-10 minutes fully closed. The overall fuel savings was significant…somewhere around 10% or so. Again, rerun these tests to get better numbers, most of my data was lost. I believe I tried HEET and SLX, since I didn't have pure ethanol at that time. It is probably on the old backup tapes somewhere…almost a terabyte and a half of backups…

HJ, I have it figured out. To get better numbers, I will just go up higher to test. Maybe Whitney.

Around your 10,000 feet, the b.p. should have been around 193 F. My numbers were from 50 feet above sea level.

I remember camping once where the b.p. was only 175 F. The water was boiling, but it didn't seem terribly hot for rehydrating food.

–B.G.–

There’s always the Tibetan plateau, Bob.

22ml seems a little high even for sea level, but given that there a lot of different pots that can be used with the Caldera Cones, there are a lot of variations Caldera Cone to Caldera Cone. Pot size and shape will play their part.

HJ
Adventures in Stoving

James Marco wrote: > … the controll also increases burn time from about 5-6 minutes or so to about 9-10 minutes fully closed. The overall fuel savings was significant…somewhere around 10% or so. Again, rerun these tests to get better numbers, most of my data was lost. I believe I tried HEET and SLX, since I didn’t have pure ethanol at that time.

Interesting! That’s quite an extension of burn time. I’ll have to play with that.

HJ
Adventures in Stoving

This last August on my trip thru Sequoia NP, I used the CC w/12-10 stove and consistently saw 1.5 tbls. or less of denatured alcohol boil 1.5 cups of water and usually had fuel left, not much, which I recovered. Trying to remember how long it took, that was pretty consistent also.
Duane

Bob Gross said
"Even though the titanium caldera cone doesn't weigh much, it is a bit bulky, even when rolled up. Aluminum foil doesn't make such a good windscreen, but it folds down tiny and weighs almost nothing."

you could copy the trangia's storm-proof, for cone-like efficiency: stop top of cylindrical foil windscreens's below pot edge (like on a real trangia), then an upside down foil-flan-dish lid could be used similarly to trap the hot gases just like a real 27 or caldera cone/clone.
If a flan case is too hard to pack, perhaps just use a foil disc lid which is wider than windshield?

"you could copy the trangia's storm-proof, for cone-like efficiency: stop top of cylindrical foil windscreens's below pot edge (like on a real trangia), then an upside down foil-flan-dish lid could be used similarly to trap the hot gases just like a real 27 or caldera cone/clone.
If a flan case is too hard to pack, perhaps just use a foil disc lid which is wider than windshield?"

This doesn't make any sense. If you aren't using a caldera cone, then you have to carry something extra as a pot support. What is a flan case?

–B.G.–

Bob Gross said made no sense:

You stated a preference for cylinder windscreens (for packability) hence I presumed you used a burner that doubled as a support (eg cat stove) or a burner and separate stand:

in which case to get cone like efficiency/enclosure you could use a tall windshield and seal the top with a pan lid which is larger than the windshield: like a trangia.

A foil flan case is like a foil pie dish but with vertical sides, like a trangia frypan, but lighter!

Diagram of trangia storm mode:

"You stated a preference for cylinder windscreens (for packability) hence I presumed you used a burner that doubled as a support (eg cat stove) or a burner and separate stand: "

Alan, you are dreaming. I never stated anything of the kind.

I stated that I did not like the packability of a Caldera Cone, and that has little to do with cylinder windscreens.

The 12-10 burner (this thread) does not support a pot by itself.

Nor do I know what a Trangia frypan looks like.

–B.G.–

Bob,

The Caldera Cone isn’t too bad on packability. I can fit it into a pretty compact package, essentially my whole kitchen except food fits into the package in this photo:

That’s my bowl, spoon, bowl cozy, stove, fuel, cone, pot, lighter, and little fuel measuring cup.

The Trangia lid that Alan is referring to can be seen in my Trangia 27 Stove Review.

HJ
Adventures in Stoving

I have both a Trangia Mini 28 stove kit and a Caldera Cone Heinekin 12/10 stove kit.
For packability they are equal if somewhat different shapes.
My heinekin can Caldera cone fits all the way inside the can. It's very durable.
Anyhow here are some pictures.
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I used the Caldera cone Heinekin for 1,100 miles before switching to the Trangia 28 for 1,500 miles.
The caldera cone was more efficient on fuel but more fuel was wasted due to overfilling and spillage when trying to empty residual fuel back into my container.
The Trangia was heavier but the stove can be easily extinguished and the lid can be screwed on so every drop of fuel is saved.
The Caldera cone fared much better in the wind than the Trangia.
As for packability though, they were neerly identical.
The Caldera cone was slightly delicate and sustained some denting etc.
The Trangia could be run over by a bus and survive.
I also have a homemade esbit stove.. okay it's a piece of tin foil.
And a homemade soup can woodburning stove.
By far the lightest, most efficient, and favorite of them all is the Caldera cone Heinekin.
If the zombie apocalypse comes I am grabbing that one.. and the wood burner.. and the Trang.. well..

"The Caldera Cone isn't too bad on packability."

Maybe, but if I omit the Caldera Cone and run with a different alcohol burner and a piece of aluminum foil for a windscreen, I can cut the bulk down by a half or more for the whole kitchen. The only time that the Caldera Cone is required is when I need to burn wood, and in many places where I operate in the parks, burning wood is not allowed.

–B.G.–

About thirty years ago I had the whole kitchen thing minimized. When I got to camp where a wood fire was legal, I would collect wood and start a fire. As it was burning down, I had a 2-ounce aluminum water ladle with a long handle. I would fill it with up to 16 fluid ounces of raw water, cover it with aluminum foil, and place it in the fire. When it boiled, I dumped the water into my cup with instant soup or whatever, and more water was into the ladle to boil again and again. The total kitchen amounted to the ladle, a small piece of foil, a plastic cup, and a spoon. When I packed up, the ladle hung off the back of my pack.

–B.G.–

"Maybe, but if I omit the Caldera Cone and run with a different alcohol burner and a piece of aluminum foil for a windscreen, I can cut the bulk down by a half or more for the whole kitchen."

That depends on your system and how you use it..
This is my 550ml version with a 250ml (8.45 oz) fuel bottle .
as you can see I fill the cone with bits that I would take anyway so I would not in fact save any space by using a generic screen.
But I would need to take more fuel with another combo so in fact increasing the needed volume.
I only boil water with that mug (occasionally make tea) and use the container as my re-hydrating "bag" and the top as a mug.
(the third picture has a 700ml pot if you want to use the pot to re-hydrate and eat from…)

The 250ml fuel bottle does me for 4-6 days depending on temps.(95% Ethanol)
Franco

Matthew:

Interesting choice to go from the Caldera to the mini Trangia! The Trangia is convenient with the ability to snuff the flame and the fact that you don’t have to try to dig the fuel back out. I do like the convenience of the Trangia (but not its weight).

My testing (Caldera Cone vs. Clikstand Alcohol Stove Tests) confirms your experience: The Cone is more efficient.

QUESTION: Did you add a windscreen to the Trangia? The mini Trangia “out of the box” has pretty poor wind protection.

HJ
Adventures in Stoving

Bob,

I think I’m with Franco on this one. The shape is different, but considering how well everything nests together, it’s hard in my mind to get something that’s more packable. A long, tall shape works well in my GoLite Pinnacle.

HJ
Adventures in Stoving