Custom Size Tri-Ti Calderas are Coming!

Any news on this? Looks great. I wonder how it will compare to the bushbuddy… anyone?

The most obvious difference I see is that the Tri-Ti's don't fully enclose a wood fire – you build your fire directly on the ground and set the Tri-ti over it. So unless you're camping in a place with a previous campfire, you will be leaving a burn scar on the ground. The Bushbuddy completely contains a fire, so, if you're smart about where you use it, there should be no burn marks left on the ground.

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Dave-

They actually include a Ti bottom for $15. I was concerned that this made the caldera cone a rigid system, so I e-mailed the folks at Trail Designs and they wrote back super quick.

I asked 1) whether or not the "floor" made the system rigid, and 2) if they had seen a performance difference in windy conditions with a deeper handle opening… a silly question as Rand would point out:

Jed:

That's what we're shooting for….unbridled excitement! :)

As to the floor…..actually it is simply a sheet of titanium cut to be slightly larger than the
bottom of your cone. It isn't "integrated" in any way. The cone just sits on top of it. So, if
you had your own ti-foil, you could just use that. We are mainly offering it as a service in case
you don't have access to any. Pricey stuff for individuals to buy in small quantities.

As to performance differences….first I'll go on the assumption that your question is about
performance of alc. stoves/esbit….and not wood…..given that the concept of easily available
wood kinda blow the whole efficiency question out of the water. So, with that caveat, no…..we
really haven't seen any significant difference. In the end, the handle hole opening in most cones
is not appreciably smaller than the handle/wood opening in the Ti-Tri.

Hope that helps….let me know if you have any other questions.

Rand :)

I am still interested to see how the Tri-Ti Caldera stacks up against the bushbuddy (dual-combustion, super catchy ad on the BPL store website)… the bushbuddy has quite a hold on me with its "neato!" factor, but the Tri-Ti may pass it. It would certainly be cheaper to have a system that allows the possibility for using alchohol or esbit OR wood.

Jed,

I have been using a Bushbuddy Ultra for just under a year now and can't recommend it highly enough. It just a fantastic little stove that boils water rapidly and the fire is easy to keep going using small twigs. In addition to being an efficient stove, it is fun to operate.

I've said this before and I'll say it again:

BB is the cat's meow (both "neater" and "technically" more efficient), IF you plan on wood being your sole (or 95+% use) fuel source.

However, the Tri-Ti is 1) Less Expensive (with the new custom program), 2) Lighter, 3) Better use of non-wood fuels…

If you are planning on ANY fuel flexibility at all (me, I plan on using solid fuel if a. I want something quick, like lunch or b. wood is sparse or c. a good burn site doesn't show itself), the TT trumps the "extra efficiency on wood" of the BB.

Even weather compatibility trumps. Lighting solid-fuel (esbit-etc) and using the TT in the rain is way better than trying to get a BB going in the rain… BB still works, don't get me wrong.

Basically, if you want the most k-a woodstove on the market, and the bragging rights of such, buy the BB. If you want the most usable option, but the TT.

PS – The BB really only shines if you use is as meant… as a partial gassifier… if you load wood like most people do it's benefits get smaller.

PPS – I'm living what I say… I had a SP900, but bought the TT Kit over the BB (which fits perfectly in the SP900) because the real flexibility was such a trump card. Now, I still plan on buying a BB "someday" however I just ordered a custom-sized TT for a smaller pot I like… so… BB is still "someday"

PPPS – Note, by efficiency I strictly mean % combustion of teh wood fuel source… and do not imply user friendliness… or anything else.

I have had a few conversations with Rand over the past few days about the Ti-Tri and cooking efficiency in general that I think might useful:

"One of the bigger mis-conceptions about titanium is that it is extremely light. More correctly,
it is extremely light in comparison to metals that have similar structural and thermally stable
properties like steel. However, in comparison to aluminum, it is actually 60%ish heavier by
volume. Now, since it is stronger than aluminum, you can use less of it…..so….in the case of
things like pots and cones, we find that the weights are about the same. For the 550….expect
the cone to come in around 30 grams.

On a side note….aluminum has MUCH better heat transfer properties…..so as a pot material, it
will conduct the heat to your food/water 10 times easier than titanium. If you got the money,
titanium is a good way to go….but people really overlook the strengths and advantages of
aluminum.

Now, back to the cone. The real advantage with a titanium cone is not in the weight of the gear
over an aluminum cone. The advantage is in reducing the weight of the fuel. With a titanium cone
you have the option to burn wood…..and potentially carry less alcohol/esbit invested weight in
the infrastructure (ie, the cone)."

"Relative to the material properties and their effect on efficiency. We have noticed a VERY minor
performance improvement with the aluminum AGG 3cup pot over a similar size pot like the Evernew
0.9. This efficiency is something we have seen as an aggregate/average effect over thousands of
burns. On any given day, with any given temperature of the water/fuel/air….or any given
altitude….or any given relative humidity….or one of a hundred different variables…..this
minor efficiency can go away. My position has always been that it is the aluminum that helps that
along….my partners aren't necessarilly convinced. So, we really don't see huge
differences….not differences large enough to make any kind of recommendation to direct a
purchase.

As to the material properties of the cone. Here again, the differences are minor….and I don't
know that we've really "seen" them quantitatively on the test bench. The issue here is that the
convective heat transfer effects of the stove in the cone are so large compared to the effects of
a minor change in material properties, that it gets blurred in the experimental error introduced
by temp/altitude/humidity/etc/etc. In theory…..a titanium cone will be more of an insulator
over aluminum…no doubt about it. Will you "see" that? Perhaps….perhaps not.

One other note on the pot material properties. While aluminum is a great thermal
conductor….that is a double edged sword. It is excellent at getting the heat from your stove
pumped into your water. However, it is equally efficient, after the cooking process, at
transferring the heat OUT of your food back to the atmosphere if you don't use something like a
cozy. So be careful in thinking through the pot material decision from start to finish.
Interestingly enough…this is another hidden benefit of the Caldera Cone System. If people leave
their pots sitting on their cone, or return it there after pouring out their stuff…..the cone
keeps the pot out of the wind and up off the ground…..in effect acting like a "poor man's" cozy.

Finally, one comment on pot "shape". While we see similar performance from cone to cone and pot
to pot…..comparing Caldera efficiency to non-Caldera performance….we see HUGE benefits with
the Caldera on the taller/skinnier mugs/pots. This is mainly because the surface area on the
bottom of a pot/mug is too small to really take advantage of the heat source when using a standard
stove/windscreen. Inside the cone however, we capture all that heat and pump it into the sides
giving us a distinct and measurable advantage with "mugs". Once again….tons and tons of
variables to consider."

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Joshua et all-

Thanks for all of the information.

As Joshua was saying, for the cash strapped college student (moi), I think the major factors come down to price and versatility.

Its like having a job interview at MacDonalds. Sure, you could spend $1000 on an Armani suit, look better than everyone else, and definitly get the job, or just go in your track suit, look slightly less stylin', and get the job anyway.

Ok bad example. Both are extremely elegant systems. Bottom line: purchasing a caldera cone and a bush buddy vs.purchasing a single Ti-Tri? K.O. to Ti-Tri!

Invest in the custom Tri-Ti, cause you can't very well run out and machine the titanium in your kitchen. But you CAN (HAHA, a pun) make yer own Bushbuddy.

Joshua, I'm interested in chatting more about your realization that the Bushbuddy is a partial (passive?) gassifier rather than a full-blown (oh jeez, another pun) downdraft gassifier. The more research, building and testing I do substantiates that observation. But I'm really interested in your methods for preparing and feeding the fuel chamber.

-Michael

Joshua said, "PS The BB really only shines if you use is as meant… as a partial gassifier… if you load wood like most people do it's benefits get smaller."

What is the proper way to load the wood?

Hey all-

Could one use a piece of heavy duty aluminum for a removable "floor" on a wood burning stove such as the TT? Or would the aluminum melt?

-Jed

Michael,

That is an impressive DIY BB in the photo. Can you please describe it's construction? Is it the same design as the BB?

I’m sure there’s a gauge of aluminum that would tolerate the direct heat but I don’t know that it would afford any cost savings over the offering of $15 for a Ti flooring. BUT, I’m pretty interested in these possibilities:

Titanium .028 12″x12″

And expanding on the potential to find sizes of sheet titanium sufficient to make a cone. I’ve reconsidered the possibility of doing light machining of the material with the same tools as needed for steel.

John:
There’s a refinement of my DIY BB that I need to play with before it’s ready for public consumption. Give me a couple days, I’ll iron that out and post the details.

Michael S – Nicely built. Is that the one that I’ve seen that uses a quart paint can and a pint paint can?

Michael S & Bill B – Passive Inverted Downdraft Gasifier stoves are meant to be batch loaded with wood and lit from the top. Why the BB should ‘technically’ be classified as partial is that the airflow isn’t tweakable, combined with the fact that users don’t tend to batch load it properly it only achieves ‘partial’ gasification.

See John R’s Comment and Drawing for how IDD gasifier’s work.

Now, even if you don’t batch-load the BB, it still makes a hell of a raised-floor combustion-air-preheating stove. Somewhere Ryan J has pics of them using the BB to burn Moose Droppings for fuel. Not something I would use any old woodstove to do.

Jed A – Based on my younger days of ashifying Aluminum soda cans in normal campfires, I wouldn’t trust Al for direct application / support of wood flame for any length of time. Realize, if you’re using it just as a windscreen, ala Dan A’s 45 G Woodburner (I’ve seen pics of someone wrapping an Al can around it to block some wind) is probably doable. But I wouldn’t use Al as a burn floor over an extended period of time.

Michael S – TiGoat sells Ti Foil that you might also look at.

Et al – I’ve considered modifiying my TT to add a raised floor out of Ti.. if I ever get around to it, I’ll post pics. However, doing so is likely to be subjecting myself to feature creep (TT is already pretty dead simple) so there’s a good chance I may never do it.

Joshua, can you elaborate on what you mean by "batch-load" I might understand but want to be sure.

“batch load” – Break up a bunch of sticks (roughly pencil to thumb thick) into… oh… about as long as your thumb… dump them in the BB… shake a bit to settle… make sure not to fill above the top holes… light FROM THE TOP… a bit of alchol typically works well… as you get better with it, any tinder will work as well…

Oh, and ‘thinner’ stuff should go on top, if there’s a variety.

Here’s some decent links (one of them has a real good pic of the batch load process)
WoodGas Stove –
Garlington Wood Gas Stove –
Wood Burning Stoves –
Wood-gas stoves –
A WOOD-GAS STOVE FOR DEVELOPING COUNTRIES –

Note, there are some of these whom some people would argue are not gasifiers at all. In reality they are just very partial gasifiers.

I have built a homemade stove out of British cans that works and has a flame pattern like a Bushbuddy. Although people call these downdraught gassifiers they are not. Without powered fans hot air always rises. What happens with the bushbuddy is that some primary air comes in the outer casing, over the ashpit, and burns the wood upward. Smoke and invisible CO and volatiles and flames come out the top of the wood. Meanwhile some other air comes in the outer casing and is preheated in the annular space between the walls. It comes out at the top of the firebox and what you see is a jet of hot air burning as a flame in the burnable gases and flame over the wood. No woodgas leaves downward through the grate, because the flow of air is in the other direction. So it is best described as an updraught gasifier with preheated air. It works best fed steadily, not in batches. When it is properly fed and up to temperature it burns all smoke so is a full gasifier. It makes a lot of white volatiles smoke before there is enough heat to preheat the secondary air enough. Then suddenly the secondary air ignites in the volatiles and the smoke disappears. The important thing is the preheat. It allows less suitable fuel to be burnt
Downdraft gassifiers need powered fans to drive the gases the wrong way, they probably do work best batch fed.
My stove and its 1 litre pot and foil windscreen weighs 200 gram, just over 7 ounces. Everything nests in the pot to make a package 110mm 4 1/4 " diameter 160mm high 6 1/2"

Derek,
I agree with your analysis. I've fooled with these puppies a good bit and your contention that the top flames – exiting from the liner into the core are simply CO and heated air seems to be correct. The pattern is primarily that of air (albeit, preheated) being introduced into a hydrocarbon-rich zone. And you are right, the action is convective and, naturally, upward. These are still good stoves, although I have not decided if they are really superior to a simple can/flue stove – which has the advantage, potentially, of a larger fuel volume.

Vick,
I agree with you that potential small fuel volume is an irritation. However My preheat jacket is part of an aluminium can weight about 20 gram. The firebox of mine is about the same dimensions as the Bushbuddy. A larger firebox would be of steel. I dont know how much more volume you would get for 20 gram.

Derek: Can you post pictures of your wood burner stove. I've been looking for a good aluminum outer can for my DIY BB. I have created one using a Heine can but would prefer a larger diameter can so I can have a larger fuel chamber. Also, the height is unnecessary and makes for a lousy fit in my pot. I personally think it looks damned cool, just impractical.

-Michael

Michael,
I am afraid I do not have photo's ready and would need help in how to load an image onto this site.
However I have pasted the important parts of the TGO site thread that gave me the info about the aluminium can. The one I got is Japanese imported into England.
The can is available from Mount Fuji International (I think it's mountfuji.co.uk, but if you type in either, it should get you there). The can you're after is the Asahi Super Dry 2 Litre Giant Can. The beer, of course, comes free with the can, but I really couldn't recommend drinking it. Apparently, it's made from rice.
Asahi Super Dry 2 Litre
Diameter: 11cm
Height: 21.4cm (that's the height to the rim. The can is actually higher than that as it's a cone top, not a flat ring pull top).

Eddy Meecham also had found an even bigger Japanese can not available at all in the UK:

"I even found a 3 litre aluminium beer can (which I'm reliably informed is the largest aluminium beer can ever manufactured. Anything above 3 litres is steel), but I could only get it from an American beer can collecting site. Sadly, I'm so obsessed with this affliction called Ultralight, that I payed far too much to have an empty beer can shipped from the US. I feel I should start a penitent forum post on the ecological unsoundness of ultralight obsessiveness.

Sapporo Draft Beer 3 Litre
Diameter: 13.4cm
Height: about the same as the 2 litre can (I can't say exactly, as I only have a cut up can)".

My 1 litre pot is the bottom 1 Litre of the Asahi can, my preheat jacket uses the top part with the conical top cut off to leave a ring that hangs it from the top rim of a steel firebox can. The jacket has a vertical slit, almost to the top, to allow it to nest over the pot for storage.
my fire box can is 100mm diameter by 120mm high, steel. There are many such cans in UK. It is divided: 20mm of ashpit then a grate,(this sits on 2 titanium tent stakes) then 100mm of firebox with a ring of secondary air inlet holes at the top. A little bit of the can top is retained as a ledge for: a 95mm diameter by 100 high 1 lb treacle tin as a pot stand, this also nests for storage. I also manage to roll a large foil turkey envelope folded around the firebox and fit it in the pot. This is a very good high windshield that reaches halfway up the pot.
sorry the photo is hard for me. I hope the description helps.

I can see now how to load images. When I have time to take photo's of my stove I will post them

My custom Tri-ti for my Brasslite 600ml has arrived.

I look forward to testing it out in alcohol fuel mode and wood burning mode in the coming days. Here are the weights in ounces:

alcohol stove: .6
Fuel bottle with measuring cup: 1
2 titanium stakes: .6
cone: 1.4
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3.6 ounces total [not including fuel weight and cup/lid weight]