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> Also one of the advantages of a cone is the structural strength, [...] a cone utilises the inherant strength and rigidity of the triangle in it's structure, a cylinder doesn't have this advantage

Indeed.

<in reply to: b a>

Hybrid cylinder/cones are possible, but the forces at the union of these two structures are interesting.  When you send me a PM with an email address, I'll send you the script and you can have a play with hybrid paper prototypes, and see how stable they are.

As for the 'special 12-10 burner', it's not really that special, just suitably sized for efficient burning within a cone.

> NB shouldn't the lower vent hole area in a clone be based on the side holes in a trangia (not in burner supporting base), as the side ones are the limiting factor?

We certainly need to use whichever is the lower area of the side and base holes.  It's three years since I started the the thread, but I think I looked at the areas of both, and found the base had the smaller vent area.  I may check again, but, after all, it was only a target figure, rather than an absolute figure.

I missed Benco's pictures...

Benco, how does your joint work?  I can't see any tab in the handle area, so I'm assuming the entire handle opening it folded in.  Since the lower tab also seems to be folded in, this means you'll have to unfold/fold a tab each time you use the cone.  Which wasn't the idea...  The idea is that one tab is folded in, and the othertab (on the other end of the clone) is folded out, and the joint is made by sliding the slots into the tabs; no more folding is ever needed, once the tabs are made.

The other thing to bear in mind with the holes is that this script thing started off purely as a 'research vehicle'; an idea that came from the design of a conic-walled burner.

It was never intended to be a Design Set In Stone, to be followed at all costs Otherwise You Will Die...  That's why there are so many parameters that the user can set to choose hole sizes, number of holes, etc. to see what works for them, their pan, and their burner.

The second row of holes was introduced to allow users to experiment with how many holes were actually needed.  Even if you print off a template with the default size and number of holes, you're not obliged to punch them all; after all, you can punch a few, and see how the clone works, and, if it smells unpleasant (sickly-sweet), or is sooty, then you probably need to add more holes.  That's a simple matter of putting the template back in place, and punching a few holes.  If you're really fancy, you can test the exhaust gas with a CO meter, or combustion gas analyser.

Of course, it's easier to add more holes than it is to take holes away... the latter can be done to some extent by using aluminium foil 'flue tape' either side of the hole.

> I wondered if a cone to fit the outer trangia 1Litre pan would also fit the inner, or would the inner need to sit on tent pegs (like caldera sidewinder)?

Not sure, but I suspect not.  It might be possible to find a 'pan circumference' that suits both pans.  I'll check this evening, if I remember.

I'm planning on making a cone out of titainum foil ordered from TiGoat. (.005") I believe.

Apart from the weight my consideration for building this out of titanium was potential wood burning capability. I read some of the posts about the thickness of the titanium vs. resistance to heat etc. 

Is anyone aware if this thickness would withstand a woodfire boil? If not, I noticed there is an inferno option as well. I dont quite understand how it works. A second cone to be placed inside the first?

The inferno insert is inverted; I have a tri-ti....but alas no idea of how thick the foil is...

I have a CC Sidewinder (i.e. entire stove fits in my 3 cup pot) with the Inferno woodburning kit which consists of an inverted cone and elevated screen mesh bottom.

 The inverted cone touches the outer cone all the way around at the inner cone's top edge.  The reason for this is to create a way to pre-heat combustion air for better combustion, exactly as the Canadian Bush Buddy does. NOTE: the Inferno inverted cone has strategically placed holes around the top to draw pre-heated air into the combustion area.

I can cook with the Inferno adapter for 20 minutes on two handsfull of sticks.

In very windy weather I use the Inferno cone around the Gram Cracker  ESBIT tab holder to reduce the effects of wind and concentrate the heat. ** Also I hold the CC stove down in high winds with an upwind Ti stake thru  the outer cone's lowest slot and a hole I've drilled in the Ti base.                                 

The TiGoat foil has been used by many people to make wood stoves.  Have a look at the MYOG forum on www.backpackinglight.com for examples.  I think you'll have to make both inner and outer from Ti, as the top of the outer is still exposed to the considerable heat of the wood fire.

The Infernal cone is inverted, and sits inside the normal cone.  I thought it was fairly clear in both the readme.doc and the postscript, but maybe I'll have to make it a bit more explicit somehow.

It's also probably worth reading this thread in full, as the Infernal option is discussed.  Here's a picture of a paper version:

As mentioned in the thread, I haven't made or tested the Infernal option, as I don't use wood stoves, and Ti foil is expensive.  Feedback from anyone who builds one is very welcome.

Hi CP,

Thanks so much for the clarification, the links, and the email. You're description of the infernal cone does make perfect sense. I was just unfamiliar with the concept of an inner cone altogether. I didnt even realize that was how the trail designs version was built, and was a bit confused. All makes sense now.

I'm optomistic that the .005 ti-foil from titanium goat will do the trick. It IS indeed expensive, however I think i paid $66 bucks USD shipped for 12" x 48". Plenty of foil for the cone, the infernal option, and the floor. The "out of the box" model from trail designs is right at $130 USD BEFORE shipping. So i'd say you'd be close to $140 USD out the door.

All cost aside, I just really enjoy doing this kind of stuff, and i'd love to provide feedback on a ti-foil version of the cone w/the infernal option. My version will still be less than half the price of Trail designs and it will give me dual fuel capability. Wood burning for me is really just a back up. I like equipment that has dual purposes, or dual capabilities of some kind. and.. to be honest. I just like playing with fire..and experimenting with stuff.

Anyway, Thanks again and as soon as I have one built i'll certainly post feedback.

Cheers,

I'd certainly suggest starting off with a small number of holes, and seeing if you need more.  Putting holes in is relatively easy.  Taking them out isn't...

As for air control, well, you could use the system of a secondary conic collar around the base, with holes that align with those on the outer cone.  By moving the collar around the cone, you can control the size of the air gap formed by the overlapping holes in main cone and collar.  I've seen this system used on some alcohol burners (which I don't think is wise), and we discussed it on a woodstove thread on OM, only aimed at cylindrical food can stoves.