I mentioned previously (here) that (inspired by Tallbloke) I'd been experimenting with an alcohol-fueled volcano kettle made from aluminum cans. I came up with a novel (to me, at least) stove that works with them and I've written about it in some detail here. The quick summary, though, is that I've got an inside-out stove fit to an inside-out pot which is reasonably efficient (< 14g alcohol) at boiling a couple cups of room temp water, hanging, perhaps, from a tree branch.

Hi Eric,
Interesting looking unpressurized? stove. And neat looking kettle. I'd guess with that design and the efficiency you're getting the boil time is around 10 mins? If that is holding a full two cups, it must be a longish can. Is that one of the Asahi's again?

Edited by tallbloke on 09/28/2008 04:01:07 MDT.

Nice work! Couple questions:

How did you make the chimney holes in the beer cans so they fit so well?
Could you use a similar system but make it into a wood burner (for example, extend the chimney down a bit so it becomes a stand, add ventilation holes and a wire mesh screen, and then throw in your tinder and light?)?

Thanks for sharing!

I'm working on a woodburner which will give dual use for my kettle design and normal pans. It's going to be made out of some 0.4mm titanium sheet I got off ebay formed into a tube which will be a snug fit to the kettle diameter for optimum heat transfer. This will sit onto the grate pan, also Ti, and double as the air intake sleeve for using the kettle with an alcohol burner.

The exhaust vent holes around the top edge will allow heat to flow up the outside of the kettle as well as the inside, with a light foil windshield providing shelter around the system. This way, the kettle can be lifted clear of the burning material for pouring or replenishing fuel without having hot ashes spilling.

Casey - Thanks! I cut the chimney holes with a 2-1/16" (Starret, multi-purpose, yellow) hole saw. Then I used just a little 180 grit, then 320 grid sand paper to smooth out the hole. It's almost a good enough fit to be watertight without glue.

I'm not very knowledgeable about woodstoves, but I think the chimney (2-1/16" of course) might be too narrow for a good, long enough burn. And I think you'd need a separate stand, or want to hang it - pretty narrow to use the chimney as a stand. I don't think you'd want to add secondary vent holes since that would tend to focus the flame into the middle of the chimney; the laminar flow of heat up the sides is key in my design. But maybe things would be turbulent enough, and efficiency being less important with wood, that that would work.

Tallbloke - Yeah, the stove is just a fiberglass wick-filled, otherwise open, alcohol burner.

I've got two kettles, one made from a 23oz Heinekin keg can, which has capacity exactly 16oz, and the other from a 1L Asahi can, with capacity something like 22oz or 23oz.

A 15oz boil takes 7-1/2 minutes in the former kettle.

More details here! http://fredricksen.net/kettle/

Edited by efredricksen on 09/28/2008 10:19:48 MDT.

Eric, excellent write-up on the website, and great performance from the kettle/stove. Well done!

The extra height Asahi kettle may be cooling the exhaust to the point where it loses velocity and prevents sufficient flow of fresh oxygen past the burner. I got around this by reducing the cross sectional area of the chimney towards the top to produce a venturi effect on the gasflow.

Achieving this involves some red bull origami....

Edited by tallbloke on 09/29/2008 00:30:07 MDT.

My apologies for barging in but there have been some PM issues...Rog, I have sent you a couple - if your still interested in an axe, e-mail me at:

steve at essieinc dot com

Very sorry fellas...

by the way, nice stove! :)

> some 0.4mm titanium sheet I got off ebay formed into a tube

I would be interested in hearing how you do this. It is not easy!

Cheers

> some 0.4mm titanium sheet I got off ebay formed into a tube

I would be interested in hearing how you do this. It is not easy!

Cheers

Hi Roger, It involves wiring the sheet around a suitable diameter steel tube, such that the grade 2 Ti is within the limits of elastic deformation. Then heating it to around 650C to anneal it so it normalises in the curved shape. Then repeating the process with smaller tube until you get down to the desired diameter.

As you say, not easy, but not rocket science either. :-)

Hi Roger T

> wiring the sheet around a suitable diameter steel tube, such that the grade 2 Ti is within the limits of elastic deformation. Then heating it to around 650C to anneal it so it normalises in the curved shape

I was afraid you were going to say that. I have done it with hose clips, and it was still an utter pain to get it to START curving at all. However, I was starting with 0.55 mm hard 6Al4V titanium sheet, which is not meant to be treated like that in the best of circumstances. I ended up buying CP Ti tubing - works much better!

Cheers

We'll see how it goes with grade 2. Any idea where I could buy 3"dia x 0.02"wall tubing in short lengths?

Edited by tallbloke on 09/29/2008 10:11:03 MDT.

Hey Roger,
Titanium Joe (www.titaniumjoe.com) has 3" ti tubing with a 0.02" wall thickness for $1.66/inch. His website states it comes in a length of ~100", but I have had him cut stuff for me before (I think it's a $10 charge). He may have a minimum charge of $100 or so...I usually end up buying a bunch as shipping kills me.
HTH,
Steve

Thanks Steven, how's the Ti Goat stove holding up?

I've bought from TitaniumJoe a couple of times. Even with the hassles of shipping international, he has been reliable.

Cheers

Actually, I should be more specific, it's not the shipping that kills me, it's the duty on importing the stuff.

As for the kettle, held up well for a 3 day trip a few weeks ago...but it is begging for some upgrades. :)

"The extra height Asahi kettle may be cooling the exhaust to the point where it loses velocity and prevents sufficient flow of fresh oxygen past the burner. I got around this by reducing the cross sectional area of the chimney towards the top to produce a venturi effect on the gasflow."

Ah! I hadn't considered that possibility. Interesting. Perhaps I'll try raising up the wick so the stove burns a little hotter; I figure that might make some difference too.

> Perhaps I'll try raising up the wick so the stove burns a little hotter; I figure that might make some difference too.

That may help but at some point you'll find the chimney volume at the lower end isn't sufficient to get a complete burn. Having played with the variables for several months, I'd say that your heineken can design is pretty close to optimal.

14-15oz of water is sufficient for a noodles and tuna meal plus drink for one or two burns for meals and drinks for two I reckon. If you need a little more you can squeeze more capacity out of a fosters can but you'll lose the nice rigidity of the heineken keg.

Having said that, I'd love to get my hands on a couple of the big asahi cans to experiment with, as taller/narrower *should* be more efficient if the chimney shape/size is right. However, they're not sold in the UK and all my emails to asahi have so far fallen on deaf ears...

The other factor is stability. The heineken keg form factor is perhaps the best tradeoff between efficiency and safety. I like your hanging bail idea, though how practical it is for treeless wilderness I'm not sure. Hanging the kettle from the pole inside the tent with your open chimney-top design would have me a little worried about my precious silnylon canopy. :-)

Having said that, I'd love to get my hands on a couple of the big asahi cans to experiment with, as taller/narrower *should* be more efficient if the chimney shape/size is right. However, they're not sold in the UK

Roger,
I have one, a 2 litre Ashhai can to spare. I would swap you for one of your kettles. Or otherwise you can get them, or I did, from www.mountfugi.co.uk. Unfortunately/fortunately my one comes without the beer.

Hi Derek,
What are the dimensions?

Eric: I appear to have hijacked your thread, again. LOL. :o)

Very inovative design of the burner. Very high tech looking. The use of aluminum would be my first choice also. The cost of titanium is prohibitive and is also hard to work with.

You've done a great job explaining the stove on your site, well done!!!!