A simple alcohol stove more fuel effecient than the Jim Wood Super Cat?

[Kevin Beeden]

> Yes, my jets all bloom nicely. I suspect an ill-fitting inner wall.

Jim, my apologies for the terse comment last night; I was being thrown out of the building…

Since these burners are a low-pressure jetted design, they do need a reasonably gas-tight fit between inner wall and the pressed ring or dimple, otherwise vapour simply leaks into the inner reservoir rather than coming out of the jets. So you need a clean pressed ring, with no dings, and good, parallel edges to the inner wall. Also, the wall must be big enough that it's held firmly between the top and bottom halves of the burner; if the side walls of the cans are too big, the inner wall will rattle about with a big gap… Also, I suggest using little fuel ports in the bottom of the inner wall; make sure you insert the wall the right way up, and that the fuel ports aren't at the top. I speak from shameful experience, of course…

Having made the point about the need for a tight fit, I'll note that I don't use any sealant or glue on either the inner or outer walls; simple press-fit seems tight enough IME. Glue is only needed if you follow the instructions at AGG or Zen, which suggest an outer can only half the height of the burner, which I think is a flawed design; using a full height outer wall making an interference fit with the strong 'shoulder' of the inner can results in a much stronger burner that needs no glue.

Not sure if your burner was built using my OM article instructions or one of the many other sets on the web, if not, you might find some helpful tips there.

> I found the thread on OM about your clone and it's really impressive

Thanks; it's now the product of three & a half years' tweaking, starting, coincidentally, from the design of the conic wall of the burners. It was originally about 50 lines of code, and it's now over 2000…

> I really like my whole cookset to nest neatly in my pot.

Me too; that was the rationale behind my SqueezeBox Stove; to come up with a windshield/pan support that would fit inside the pot.

The Flissure joint for the clone seems to work pretty well, and, when you get the hang of it, doesn't take long to put together (it takes me about 45 seconds to unpack my cook kit and assemble the clone). Trail Designs started looking at a horizontally-split design some time ago, but, for some reason, they dropped the idea, saying that it was too difficult to make. The clone script at one point had a mitre joint as per TD, but I don't like it, and prefer my simple slot and tab joint as simpler to make & mate, and seems more robust in use.

Drop me a PM with an email address and I'll send the script & instructions. I'll also send a template script for the conic-walled burners.

> Anyway, I am glad someone found a use for it.

It's a neat idea, and neat ideas are always worth sharing, even if they only serve as the stimulus for a follow-on idea. Essentially, it seems to be the same idea as Jon Fong's white gas burner earlier, only with more pleats. Despite using folded sections for the SqueezeBox, and for a vaned Kelly kettle idea, I'd not seen the technique used for a burner before.

Having only recently dismantled the 'stove assembly facility' from my front room to make way for guests, I can see that I might have to re-open said facility… I might use the same technique I used for the vaned kelly kettle inner wall, which was to score fold lines with a ball-point pen. It might also be interesting to try making a 'throttle' with an outer ring that can be turned to change the size of the air intake ports at the base of the can; close up the holes for a slow simmer, and open the holes for a fast boil.

[James Marco]

"Having only recently dismantled the 'stove assembly facility' from my front room to make way for guests, I can see that I might have to re-open said facility… I might use the same technique I used for the vaned kelly kettle inner wall, which was to score fold lines with a ball-point pen. It might also be interesting to try making a 'throttle' with an outer ring that can be turned to change the size of the air intake ports at the base of the can; close up the holes for a slow simmer, and open the holes for a fast boil."

Yeah, I thought of that. IFF you are carefull with the bends on the folds, you can actually make a second cone to fit on top. The joint will act as a handle for turning it, soo, it is also adjustable between a slow burn and a fairly fast burn, besides acting as a good oxygen source for the flame. Kind'a fiddly to make, though. Never tried it, though. Sounds like it might work. provided you close the burn down a bit. You might see a slight improvement in efficiency, too. I Have NOT tried angling the pleats, either. This would also induce some swirling into the flame and promote slightly better air/fuel mixing. I will have to make one and try it again with WG. The air *should* also act as a cooler for the stove preventing melt downs and metal burnouts provided I can keep the flame stable. It may just pop out. before acheiving enough draught, though.

Good thinking!

[Hikin’ Jim]

Kevin Beeden wrote: > > Yes, my jets all bloom nicely. I suspect an ill-fitting inner wall.

Jim, my apologies for the terse comment last night; I was being thrown out of the building…

Since these burners are a low-pressure jetted design, they do need a reasonably gas-tight fit between inner wall and the pressed ring or dimple, otherwise vapour simply leaks into the inner reservoir rather than coming out of the jets. So you need a clean pressed ring, with no dings, and good, parallel edges to the inner wall. Also, the wall must be big enough that it's held firmly between the top and bottom halves of the burner; if the side walls of the cans are too big, the inner wall will rattle about with a big gap… Also, I suggest using little fuel ports in the bottom of the inner wall; make sure you insert the wall the right way up, and that the fuel ports aren't at the top. I speak from shameful experience, of course…

Having made the point about the need for a tight fit, I'll note that I don't use any sealant or glue on either the inner or outer walls; simple press-fit seems tight enough IME. Glue is only needed if you follow the instructions at AGG or Zen, which suggest an outer can only half the height of the burner, which I think is a flawed design; using a full height outer wall making an interference fit with the strong 'shoulder' of the inner can results in a much stronger burner that needs no glue.

Not sure if your burner was built using my OM article instructions or one of the many other sets on the web, if not, you might find some helpful tips there.

No apology needed. I do hope you weren't injured when they threw you out of the building. :)

Thank you for the continued help and suggestions on stove building. I don't know if you noticed, but I mentioned you in the acknowledgements in my latest blog post. Truly appreciated.

I'm not quite sure why my stove's jets aren't blooming although it may just be due to the haste in which the stove was assembled. I'm not too worried about the jets not blooming. The stove seems to be a fairly efficient design when just used as an open cup burner.

I do wonder if the jets might aid cleaner burning though. I'll have to have a look at your OM instructions and see if I can refine the stove a bit.

Even on those stoves that I've gotten the jets to bloom, there always seems to be a bit of burn from the central opening. The only exception to this seems to be a Trangia burner. I know the Trangia has wicking material inside its walls. I've considered adding something along those lines to one of my burners.

I was up late last night and about "done" right now. I do hope this post is somewhat intelligible.

HJ
Adventures in Stoving

[Kevin Beeden]

> but I mentioned you in the acknowledgements in my latest blog post.

That's very kind, Jim, but I'm afraid I don't have time to read blogs; it's hard enough keeping up with three forums…

One other possible issue with your burner is that the seal between inner wall and the can is too good, and you haven't added fuel ports to allow fuel into the 'vapour chamber' (the annular chamber betwen inner and outer walls).

If you're really into alcohol stoves, you might have a look at the monster OM 'How to make Meths Stoves Q&A' thread that runs to over 1000 posts. Don't blame me if you lose hours of your life…

[Hikin’ Jim]

Kevin wrote: > That's very kind, Jim, but I'm afraid I don't have time to read blogs; it's hard enough keeping up with three forums…

I completely understand. Nonetheless, the thanks is sincere. Your advice has been very on point.

Kevin wrote: > One other possible issue with your burner is that the seal between inner wall and the can is too good, and you haven't added fuel ports to allow fuel into the 'vapour chamber' (the annular chamber betwen inner and outer walls).

I've got the ports. I suspect it's too loose not too tight. I may have to try a rebuild and follow your instructions precisely. I think there's still some efficiency to be gained by firing the jets, and I hope that there will be a bit less soot.

Kevin wrote: > If you're really into alcohol stoves, you might have a look at the monster OM 'How to make Meths Stoves Q&A' thread that runs to over 1000 posts.

Gasp! Well, not all at once I won't, but thanks for the tip.

HJ
Adventures in Stoving

[Hikin’ Jim]

Kevin,

Is a template or instructions available for your conic walled burner? I'm curious to play with that one.

HJ
Adventures in Stoving

[Kevin Beeden]

sent :-)

Oh, and another thought occurred to me about your first burner; it may be that the vapour simply isn't meeting the inner flame and igniting. Try wafting the flame about gently after about 15-30 seconds, or using a lighter. Or simply lower a pan over the burner, which will force the flame out to meet any jetting vapour.

If you make the reservoir opening too small, the priming phase doesn't work, as it seems that the fuel is starved of air, and the flame goes out, or burns so slowly that the burner never jets. 24mm is about the limit with red bull cans and meths. I discovered this whilst experimenting to reduce the central flame, trying to shiled the fuel in the reservoir from heat from the flame, and reduce the 'exposed' fuel area that forms the central flame.

Oh, and I use a flat wood bit to cut the partial central holes, having found the centre using dividers from the edge of the dimple.

My first burner, twelve years ago, was a penny stove (not a Mark Jurey 'Penny Stove'); simply upper and lower cans, with a small central hole. It was based on a variant of the LaMar Kirby burner, but I didn't like the idea of a central screw and high pressure. All I wanted was something to cover the small, central fuel fill hole, and a penny came to hand, and worked. This is primed by putting fuel in the burner, covering the hole with then penny, and then pouring a little more fuel into the dimple; the penny stops it draining into the burner too quickly, and it will usually prime/bloom before this fuel runs out. Then it produces a 'pure jetted' burner, since there's no exposed central reservoir. It's a bit fussy about priming, and continuing to run, but it does get over the central flame 'problem'.

However, when you put a pan over an open reservoir (trangia-style) burner, the central flame is starved of oxygen anyway, and any vapour being released from the reservoir merges with that from the jets, and seems to form a flame ring, depending on the number of jets. I found 16 jets around a 250ml red bull size burner gave a flame ring, but 12 jets gave discrete flame jets.

Most of this discussed on the monster OM Q&A thread.

[Rusty Beaver]

Sorry if this has been covered here (or other places referenced too). I haven't had time to delve into this too deeply yet….and honestly, there seems to be so many stove versions and info on the web that I find it slightly overwhelming.

At any rate, do the open top jet stoves, such as the Meths Burner, require a separate pot stand or can you sit the pot right on the stove?

[Hikin’ Jim]

Hi, Rusty,

It varies by exact type, but top jet stoves generally require a separate pot stand of some type.

Side burner stoves generally don't require a separate pot support. Not needing a separate pot support is a plus. However, I've been a little disappointed by side burner stoves. A lot of time the flame pattern is so wide you wind up sending flames up the side of the pot. The weight you save by not needing a separate pot support can be negated by needing more fuel.

HJ
Adventures in Stoving

[Rusty Beaver]

Thanks, HJ. I was fearing that was the case.

In re to that pleated stove discussed earlier, I assume it also requires a pot stand, correct?

r

[Hikin’ Jim]

Oh, yeah.

HJ
Adventures in Stoving

[Ultra Magnus]

"Side burner stoves generally don't require a separate pot support. Not needing a separate pot support is a plus. However, I've been a little disappointed by side burner stoves. A lot of time the flame pattern is so wide you wind up sending flames up the side of the pot. The weight you save by not needing a separate pot support can be negated by needing more fuel."

I've never been keen on side burner stoves either. I work in mechanical design, and as far as a design goes, they just look stupid to me. No offense to those who love them, but in every way (other than total weight of a system) they stink. Pot stability- heck no… esp. when you go to smaller diameter, taller pots like 700ml mugs and beer can pots. You just better hope you have nice level ground to set up on, and hope a strong gust doesn't topple it over… And efficiency, like you mentioned, is also compromised. A good portion of the surface area of your pot is rendered ineffective, and again, gets worse wither taller, narrower pots.

All my myog cook kits incorporate the windscreen as part of the pot stand, usually with tent pegs or stainless steel wires (I may be purchasing some 1/8 ti rod from McMaster soon). My latest setup is a Caldera Clone courtesy of Captain Paranoia's post script file. My #1 dislike for Trail Designs CC is because the cone won't fit in my pot. Both systems are very stable and can take a fair amount of bumping before they will get knocked over.

I've been running that pleated alky stove through it's paces (cooked my lunch on it today) and I'm very satisfied with it. I think it would be very hard to make any stove as efficient. Many might come close, a few might beat it, but I bet none of them weigh only 3g and are as simple to make.

If you can have something so simple in design, simple to manufacture, simple to operate, and so extremely light weight, that functions so well, why would you bother with anything more complicated and heavier? What's the point? I'll give the featherlight (??) some credit for actual heat adjustability that works, but I don't need that for my bikepacking, freezerbag, cook system.

BM

[Rusty Beaver]

Thanks, guys.

BM,…I hear what you're saying about the pleated stove. It caught my eye due to its simplicity….but with a required pot stand, that means more pieces and fiddling….things I'm trying to avoid, if possible.

Back to the meths style top burner, how about extending the inner wall so it had an integrated pot stand?

[Ultra Magnus]

I think that's kinda like what Zelph is doing with his alky stoves – http://www.woodgaz-stove.com/cobalt-blue-soloist.php

Still has the downside (for me at least) of balancing a large pot in a tiny stove, and only heating the outer annular area of the pot.

BM

[Dan Yeruski]

1st came the Cobalt(side jet), then the Cobalt Blue Soloist(top jet) and then followed up with the larger diameter "GoTo" (top jet) made from a Venom energy drink bottle.
The "Soloist" met the needs for a jet stove that worked well under a Heineken/Foster's pot. Cold pot does not affect the jets.

Stove designs follow the needs and wants of everyone on this forum and other forums. Small, compact, light weight and titanium.

Concessions are made to obtain all of the above. Small diameter stoves mean you have to take your time to balance the pot. Ti stoves you have to fork out the big bucks.

So many variables. Stoves that are finicky, put a pot of cold water on top of them and the jets go out.

We sure do have fun making and designing. Keeps us off the streets and happily married.

[Hikin’ Jim]

Keeps us off the streets and happily married

Come again on that last part? (my wife is always bugging me to stop fiddling with stoves).

HJ
Adventures in Stoving

[Daniel Sandström]

I think the cat stove is a very nice alcohol stove, I love the simplicity of it.

It's a shame I use a narrow pot. I haven't timed it, but it's been nice enough given I've used it on overnighters where the fuel weight isn't a problem.
I had two thoughts.
1. I use a thin aluminum foil windscreen, as tall as the setup. I believe the flames that goes up the sides isn't wasted as many suggest, but that it does warm the pot somewhat or at least prevents heat loss.

2. Is the area directly over the catstove cool, not getting any heat at all? Or is there some hot stuff going on inside the catstove too?
To find out, I design a proper high tech testing rig.
I found out redbull cans had the same diameters as my catstove, then cut a similar diameter hole in a couple of layers of aluminum foil. –> The primary flames would then heat the foil, while I could see if the water inside the redbull got any heat.

How did it go?
Well, the can was half full and I heated the can for about three minutes. There were no boil, only some steam. I proceeded to check the temperature, my mouth said it was drinkable, warm, but not yet tongueburning.
I'd conclude that there is some heating, probably conductive heating from stove to pot. But there isn't any fire inside the stove – which I did anticipate as there's no air inside. Had to test though.

Hope it's to some interest.
Cheers.

[Author]

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