caldera cone

[Gregory Keller]

I'm just starting to play around with an alcohol stove, and looking for a windscreen and pot stand. I've built a few pepsi can type stoves to get an idea on how they work.

I really like the caldera cone as a windscreen/pot support but was wondering if there was anywhere i could get one without having to buy the stove along with it? Is the stove that comes with it that much better than something i can make? Or is it a system that works much better together than seperate from one another?

Thanks

[Mark Hurd]

Greg,

TrailDesigns actually designed the 12-10 stove that comes with the cone to burn better in a lower oxygen environment like inside the cone. They also have tuned the height of the cone to position the pot in the sweet spot of that stove. So yes the stove is matched to the cone.

Now, that said, I know a lot of folks use other stoves with a Caldera cone and they seem to work ok. So one could try it.

As to getting just a cone without the stove, I think you can email antigravitygear ( the folks that sell the cones for TrailDesigns ) and ask about getting just a cone. They can probably set you up.

Happy Trails,

-Mark

P.S.- I have tried a number of homemade stoves and bought stoves in my Caldera Cones, but I always come back to the 12-10 stove. It has just worked better for me. YMMV

[Monty Montana]

Gregory, I don't claim to be as expert on alcohol burners as some on this site are, but from my own experience with a MYOG burner and the Vargo Triad, I'd say the burner that came with my Calder is head and shoulders above the others. And I doubt my skill in making one just like theirs. However, any alcohol or esbit burner will perform better in a Caldera vs just a windscreen.

[Rand Lindsly]

All:

Mark/Monty….thanks for the support. Normally, I would let this thread run its course, but need to actually step in on two comments that were made. The statement:

"any alcohol or esbit burner will perform better in a Caldera.."

….is not actually true. The real strength of the Caldera is that it is capturing all the heat and funneling it into the pot. This is a double edge sword because the stove also has to operate in that heat. Alcohol will volatize quicker in the higher temperature, causing most stoves to run hotter, creating an even higher temperature, causing alcohol to volatize quicker, causing the stove to run faster…..etc until you get into a runaway stove situation. This happens more with the "pressure" type or "jetted" type pepsi can stoves……so much so we have seen it blow flames out the upper vents and actually damage the cone. The other situation you can get into is when the stove burns up all the oxygen inside the cone, and sputters almost out…..then sputter back to life when more air makes it in and then just go back and forth like that. It took us years and some serious development time sitting on the tailgate of Subaru's at the east entrance to Yosemite at 10,000' to fine tune a stove that would work consistently.

So…..no….not every stove does better inside a Caldera Cone. Now with that said, we would never say you can't stumble onto one that DOES do as well…..but there is no way for us to track all the variations out there and qualify all of them for use. Consequently, we restrict all cone sales to come with the stove we designed to work inside the cone. That way we are sure you will be off to a good start. This brings me to the second comment. AntiGravity Gear (our order fulfillment folks) won't sell just a cone. Sorry….but as I just described, the 12-10 needs to come with it to ensure you have a working system.

Hope that helps….and thanks again for all the support!

Rand :-)

[Mark Hurd]

Rand,

Thanks for the info. I wasn't sure what AGG could sell, and I appreciate the insight on stove performance in the cone.

Also, Congratulations on the new Caldera Keg lines!

-Mark

P.S. Love the pics. Roughly, how many stove prototypes did you guys go through before you settled on the present 12-10?

[Rand Lindsly]

> Roughly, how many stove prototypes did you guys go through before you settled on the present 12-10?

Wow…..easily hundreds and I wouldn't be surprised if it were a 1000. Every variation in Zenstoves and beyond was tried. We tried wicking, we tried insulation stuffed inside, we tried jets, penny stoves, plugs on top, hybrids, center burners, side burners, double walls, single walls, open burners, cat food cans, tuna cans, beer cans, pop cans, small cans, large cans, short cans, tall cans, candles, soy diesel, etc etc etc. Once we narrowed into the general design we have now, we tried 8 holes on the outside, 10 holes, 12 holes, larger holes, smaller holes, holes down low, holes up high, holes on the inner can in different locations, different reshaping of the top opening, different diameters of the top opening and even weird flower type cutouts. If you look closely in the second picture, you can see one of the design paths we were heading down that had promise for a while (flower cut top).
Then, all of these had to be run at different altitudes different temperatures different cone offsets and pot diameters and cone venting and on and on and on. Honestly, the number of variables in this system is unbelievable, and it is still amazing to me that we were able to finally narrow it down to something that works in unison so well.

Mark….this isn't pointed at you….but a general statement to the crowd. When we pair our stove up with the cone to sell it…..trust me….it isn't because we are trying to be stove Nazis. We've painstakingly run the experiments….and have never been able to find anything else that works as reliably over a range of altitudes and temperatures as the 12-10 we are shipping now. Not saying it doesn't exist….it' just that we don't know of it…and the odds are that a stove designed to work in the wide open environment of a generic windscreen, isn't going to expect the environment of the cone. One note….we originally had a stove called the "Caldera Cooker" that actually ran better at sea level…..but once you got over 10K, it fell apart (ask Will Rietveld!)

Again….thanks for all the support and the high level of scrutiny you all provide. It definitely keeps us pushing the design to make it better.

Rand :-)

[Jesse Coonce]

Hi Rand,

I have a Caldera as well and love it. I've been meaning to find out what the holes in the side of the 12-10 stove are for? At first I thought they were jets but no flame comes out of them, so what purpose do they serve? Thanks

Jesse

[Franco Darioli]

"Wow…..easily hundreds and I wouldn't be surprised if it were a 1000."
That made me feel better about giving up after a couple of dozen or so . I tested several commercially available types (that I already had) as well as home made versions and many of my own permutations. In the end I gave up because I was either getting a faster boil but using more fuel or using a bit less but adding 3-5 minutes to the boil time. Neither does anything for me.
Of the ones that did not work, several burned too hot, either shooting flame all over (alcohol boiling over) or snuffing the flames.
Franco
Jesse , those are for the air intake

[Monty Montana]

Rand, thanks for giving me some insight on the complexity of your product…now I know why it works so well!

[Frank Deland]

I would be one of those peolple who would have supported the comment quoted at the top of Rand's post. I have used the esbit stove purchased at BPL in the caldera system. The tablets burn longer and mmore efficiently tahn inwith my homemade wind screens. For dinner I can boil 3 cups to a boil for soup, then 2 cups to a boil for dinner on one esbit tablet. I plan to use the esbit system on the JMT in August. I also use the Trail Design esbit stove which hardly moves the scale!

[Mark Hurd]

Rand,

I know this is off topic, but IMHO I think the kind of information in your reply to my question should be published on your website to let folks know the background on your stoves. Maybe in a History section or an extended About Us section. It sets you apart from the majority of stove makers out there and people, at least people like me, would be interested in the development, hard work, and engineering that has gone into your systems.

-Mark

[Sean Walashek]

As a proud owner and end user of your product I am very grateful for your time and patience you guys put research and development.

[JJ Mathes]

Gregory- what size pot/mug are you using? I have a caldera cone for a SP600 mug that I'm not using. I'm getting ready to post it FS

[Rand Lindsly]

….and thank you all again for the support and appreciation of the Caldera system and what we have been working to achieve.

Mark….great idea about some of the history stuff. There was an early version of the esbit kit/GramCracker that should be documented along with the "slot and tab" version of the cone closure. As it turns out, with the advent of the Keg stuff, we finally hit the wall on our current website layout. The number of product offerings finally crossed over into "unwieldy". So I have been working on a new website layout with cascading menus that will make it easier to navigate. I suspect it will take a week or two to get everything moved over to the new format. At that time, I'll start looking into extending it with things like a "history" page.

Rand :-)

[. .]

Rand –

What about with larger pots? How does the same burner design work as efficiently when you bump up to a 1.4 or 2.0 liter pot? This reviewer says that a Trangia stove boiled water twice as quickly (efficiently?) in the Ti-Tri:

http://www.larsonweb.com/stoves/id3.html

What do you make of that?

I already have a bushbuddy ultra, but am considering purchasing a Ti-Tri set-up for a Firelite 1350 or MSR Titan 2l pot in order to potentially melt snow and use for small groups and windier conditions.

[Rand Lindsly]

Aaron:

We have a few different concepts here….let me address the last one first:

Ti-Tri with larger pots – With the Ti-Tri….in wood burning mode, you will most DEFINITELY see better performance with larger pots. The reason is, since the pot positioned in the Ti-Tri in wood burning mode is mostly above the cone, the majority of the heat is only able to "see" the bottom surface of the pot. For this reason, larger pots present a larger surface area to the flame and are consequently better than smaller pots in the Ti-Tri in wood burning mode.

Ti-Tri efficiency – Though your question on efficiency was not relative to wood burning, I'll nevertheless make the observation that with a comparatively unlimited supply of fuel (wood), efficiency calculations are not all that useful.

Alcohol "efficiency" – Speed is NOT efficiency….nor is it efficient. Over tons and tons of testing, we have proven to ourselves that the faster you try to boil, the more fuel you use getting to that boil. If you kinda picture it in your head, it makes sense. If you have to heat up the pot and the air and the cone/windscreen to higher and higher temperatures in order to force the heat into the water faster, you inevitably lose a higher and higher percentage of that heat into the environment/not to your water….and that loss comes at the cost of more fuel. If you want mad crazy efficient…..we can send you a stove that will boil 2 cups of water on something like 8 or 9 grams of fuel…..it will take 30 minutes or more to do it…..but it is wicked efficient! (not sure what we did with those stoves…..but we were actually able to do it). Now, as much as the marketplace talks a good game about wanting the lightest weight gear and the most efficient stoves, 30 minutes to boil 2 cups of water is a non starter. So, what we did was compromise and tried to optimize around 2 cup boils in 6 to 8 minutes. We lose a little efficiency in doing that, but fall more in the realm of the market's actual expectation. In the end, beware of using "boil time" as a metric….it will almost always come at the cost of added weight and/or inefficiency.

Kai Larson's review – Thanks for posting the link to Kai's review. It is very thorough and very positive about the Caldera. Recommend folks read it. The Trangia comments I don't doubt were stated correctly….but incompletely. Stove weight and fuel usage (efficiency) weren't covered…..so hard to describe it as a "better" choice. Also his review was written prior to the introduction of the Caldera Caddy….and his comment about snow melting I suspect was relative to the stove/alcohol function, not wood burning where snow melting is actually one of the better uses of the Ti-Tri.

Larger pot volume for alcohol – Here I think Kai slightly mis-stated something…..and if read in the context of his entire statement it is clear what he meant. He stated "the larger capacity pot [with alcohol] struggles to bring a liter or more of cold water to a boil." It is not the pot size that is the issue…..it is trying to bring 4.5 to 5 cups of cold water to a boil with alcohol that is the issue. We really don't see much of a difference with pot size. As stated above, our design parameters were to bring 2 cups of water to a boil in the 6-8 minute time frame. So….yes…if you are trying to boil over a liter of water in the system using our alcohol stove, it will take a while. It will likely still be more efficient than the Trangia….but you will be waiting a bit. If speed is important, and the heavier weight of the Trangia is not an issue, and you are OK carrying and burning more alcohol, then the Trangia might work for you. Again, as stated earlier, we don't track Trangia's design modifications, nor do we qualify it on any kind of regular basis….but it is the same "type" of stove as the 12-10 (center burn) and we have seen it work in the cone.

Hope that helps…..and I didn't miss anything. I suspect you all will let me know if I did!

Rand :-)

[Lynn Tramper]

"Speed is NOT efficiency….nor is it efficient. Over tons and tons of testing, we have proven to ourselves that the faster you try to boil, the more fuel you use getting to that boil."

I will second this observation. The same applies to the Gram Cracker Esbit stove…by slowing down the burn rate with the 'wings' , you get greater fuel efficiency. The 12-10 strikes a nice balance for an alcohol stove. I haven't tried the Trangia in a Caldera, but I have tried a lot of other stoves (from alcohol to canister) and find this is always true. According to Roger C, the same applies to canister stoves. By winding the throttle back to medium, you use less fuel overall. The best way to increase the 12-10 efficiency further is to make a 'snuffer cap' like the Trangia or Packafeather, and recover unused fuel. For reasons I don't understand, the alcohol stoves seem to burn more efficiently if you add more fuel than you actually need, but if you can't recover the unused fuel then it's NOT a gain in efficiency!

The Ti-Tri wood burner for larger pots is an absolute inferno when it's going full speed.

[. .]

Well, in order to intelligibly add to the discussion and avoid the appearance of hijacking, I think I'll need to order a Ti-tri.

One question remains then:

Should I get one to fit my BPL-1350 or my MSR Titan 2 liter?

(I rarely solo hike and have 3 jr. hiker tots between ages 2-7)

[Lynn Tramper]

"I rarely solo hike and have 3 jr. hiker tots between ages 2-7"

I would recommend the 2L cone. Not only can you cook decent sized meals, but it makes a great little camp fire to keep warm by and roast marshmallows…the kids will love feeding it too.

[. .]

Thanks Rand,

Your reply was amazingly thorough and helpful. I put the word 'efficiency' in parentheses by 'speed' because it was apparent that he left that data out of his observation (I was trying to be efficient with words ;).

I truly enjoy hearing about your product development experiments and would second the humble suggestion to put some of this on your website as you update it.

"If you have to heat up the pot and the air and the cone/windscreen to higher and higher temperatures in order to force the heat into the water faster, you inevitably lose a higher and higher percentage of that heat into the environment/not to your water….and that loss comes at the cost of more fuel."

^- kind of like a car burns more fuel when you accelerate more rapidly.

[Walter Pickett]

Hello All

I've been using my Caldera quite a lot in the last week (i.e. experimenting). Today, when I pulled it out of the case, I noticed that the two coke can parts have seperated from the primer plate. Anyone know what sort of cement/epoxy/glue I can use to get them back together?
Does Trailwise have a guarintee?

Walter

[Rand Lindsly]

Walter:

I responded to the mail you sent directly to Trail Designs. In case anybody else wants to know the answer….It is JBWeld…..and I've already offered to send Walter a new stove.

Rand

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