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

[al b]

Strange, I would have thought kerosene, being less volatile than white gas, should be safer.

[Hikin’ Jim]

Sorry about not responding in a timely manner. First, my observations about white gas, with the CONE Zone design it smells stronger than Esbit. If I re-design it along the lines of my current isopropyl stove (to speed up the time to boil), I think that the extra ports will also reduce the smell. White gas stoves are sensitive to the wind; slight breeze will cause the stove to burn yellow and create soot. I tried kerosene once and it scared the crap out of me and I don’t plan to pursue this. Zelph (Dan) has kerosene stove that he is working on and I would follow his development. Best regards – Jon

Jon, is there any chance you've got that backwards? White gasoline is very volatile, and I can see that being scary. Kerosene on the other hand almost has to be persuaded to burn.

HJ
Adventures in Stoving

[Kevin Beeden]

James wrote: 'My apologies to all.'

No apology needed, James. I know I can sometimes sound a bit severe, but it's just my rather dry posting manner*, and I don't mean to be accusatory or argumentative. It's just that I'm a stickler for detail, so if I see something I don't understand, I stick at it like a terrier until I've got to the bottom of it; either figured out where I've misunderstood, or clarified the misunderstanding elswhere…

* doesn't help being a taciturn Brit; one thing I like about visiting BPL, and sending clone scripts to the US is the really positive responses that come back. Brits might say 'thanks', but you guys come back with stuff like 'awesome!' or 'you rock!'. It might seem trivial, but those little messages always give me a lift.

[Jon Fong / Flat Cat Gear]

Fuels are a funny thing. In my mind, I have started to separate energy content with how well it burns. IMO, denatured alcohol burns pretty easily and ignites well at low ambient temperatures. Isopropyl has a higher energy content, however; it seems to be a lot harder to light at cold temperatures. My IPA stoves tend to choke off the airflow to get a clean burn (no soot), and the stove tends to burn “slower” than a DA stove. My passive white gas stove burns slower than the IPA stove. The funny burn rates may have to do with the boiling points of each fuel. DA ~ 65C, Isopropyl ~ 83C, white gas ~160 to 220 C Kerosene ~150 C to 275 C. Yes, there are a whole bunch of other factors including flash point and vaporization rate and such. The net effect is to separate “ease of burning” from energy content. I am sure that some of the informed minds on BPL can shed more insight into this.

[James Marco]

No, I checked your numbers, give or take the actual definitions on fuel heat, (wikopedia is not self consistent) then obviosly something is wrong. I checked my thermometer and it was reading a hair more than 211, so its correct. BTW, I say boiled I always call it at 200F, not 212F, I have said this probably 100 times, so, mostly I assume people know that. It avoids the big phase change at the end…Still, it does not account for 250%! I never tested 8oz water, nor 12oz. 2 cups or 1 qt (or about a liter.)
I reiterate my appology to all…

[Hikin’ Jim]

Jon,

You've obviously played with non-pressurized petroleum fueled stoves far more than I. I'm quite impressed that you've done what you have. Usually such stoves are a big smokey mess, nothing I'd ever want to have any food go near. That and having seen a white gas stove catch fire once, I have a very healthy respect for such appliances. I'm quite willing to experiment with alcohol, but white gas is something I've never been up for.

If you do put together any more vids or photos or just want to make more comments, I'm quite interested. I'm not sure how practical they are or are not for field use, but they certainly are fascinating.

As for me, I'm trying to come up with something that burns high ethanol content alcohols cleanly and efficiently. I've got something that's working pretty well, but I need to do more testing.

HJ
Adventures in Stoving

[James Marco]

As far as cone stoves, go, the most soot is generated when there is not enough oxygen to burn the fuel vapour. It emits CO and C (common soot.) So, my initial thought was to use higher heat density fuels (WG, kero.) The stove on the left was designed for that. I thought that by an application of a venturi, combined with a longer burn, I could induce a clean burning WG stove. Initial calculations showed this to be possible (http://en.wikipedia.org/wiki/Venturi_effect has several possible approaches to this…) However, the small size, about the size of a soda can, did not allow enough oxygen to heat the fuel, it kept popping out. A couple holes fixed that, but, I lost much of the clean burning I was after. It did produce a highly efficient alcohol stove.

The stove on the right was a different approach to the same problem, not enough oxygen. It burns highly efficient with clinical grade ethanol(dehydrated,)but does not burn hot enough. Again, not enough oxygen for burning WG. I have not tried Acetone yet but it has about 160% the heat capacity of ethanaol and is roughly the same as WG.

[Brian Austin]

Heavier the fuel the less likely it will be to burn.(Rule of thumb)

For efficient burning you must atomize said fuel and you must mix it with the proper ratio of oxygen. Without either said stove will create tons of soot.

Alchohol/White gas have a very low vapor pressure. Therefore they readily "evaporate" into the air, mixing as they go and therefore burn efficiently with additional pressure. This is seen by the fact that they are easy to light. That and their low ignition temperature thresholds as well. Kerosene requires a hotter ignition point to light up.

Kerosene on the other hand is far harder to light as it does not evaporate as readily. There are "lighter" grades of Keorsene like LAMP oil, which are far easier to light. Anyone with experience in old fashioned lamps knows this compared to standard kerosene. Of course its more expensive as well. Said LAMP oil doesn't create even a 1/3 as much soot as "standard" kerosene.

A kerosene burning stove is one of my wish lists top numbers. BTU/lb for kerosene is far superior. I believe that using a proper wick as in a kerosene lamp would provide enough surface area for efficient evaporation and therefore a light "easy" stove. Need to be able to roll said wick up and down to eliminate soot and provide efficient burning. This would effectively only provide one burning setting though unless one introduced several wicks that can be moved up and down independently.

If you want to create a kerosene stove, start with a kerosene lamp and work on lightening it as much as possible. Its a bit more complex than an alchohol stove, but less than a whitegas stove. Like an alchohol stove said kerosene stove can also be its storage container. "killing" a kerosene flame is pretty easy on the other hand due to its higher required ignition temperature along with its lower volatility.

[Ultra Magnus]

http://www.backpackinglight.com/backpackinglight/user_uploads/1314953824_48249.jpg
"The stove on the right was a different approach to the same problem, not enough oxygen. It burns highly efficient with clinical grade ethanol(dehydrated,)but does not burn hot enough. Again, not enough oxygen for burning WG. I have not tried Acetone yet but it has about 160% the heat capacity of ethanaol and is roughly the same as WG."

I saw a picture of that stove in another thread and I just had to make one, and as things go, I ended up making several. It's a great little efficient design that's easy to tune the heat output. My latest, best performing version, is made form a 12oz red bull can (slightly bigger diameter than a normal 8.3oz red bull can, but still much smaller than a 12oz soda can)with three holes punched in its perimeter. In this configuration, it'll boil 2c water in my Heineken pot in about 10mins flat, and keep burning for 12min 30sec on 2/3oz of denatured alcohol (controlled conditions 70f water, 70f ambient temps). It's easily just as good as much more complicated pressurized designs but significantly lighter (I think it's about 3grams) and significantly easier to use (no priming), and easier to make (no pressing cans together). It's a win-win.

I plan to post more details of my cook kit in another thread, but I did a cold weather test today. It was between 15F to 20F depending on where I placed my thermometer, and starting with 33F water it got boiling in I think 16:30 (slow) and burned out right at 17mins on a touch over 2/3oz of water. I think my failing was that I failed to insulate the stove from the cold ground. I'll have to place something under it and try it again before this cold snap ends…

Next I'll have to test it in high winds to see how well my wind screen works…

BM

[Hikin’ Jim]

Interesting. What type of alcohol were you using?

How hard is it to make the pleated conical type of burner?

HJ
Adventures in Stoving

[Ultra Magnus]

"Interesting. What type of alcohol were you using?

How hard is it to make the pleated conical type of burner?"

I think SLX denatured alcohol- we have some here at work but it's in a spray bottle (used as a solvent to clean oils off parts) that I took some from… My supply at home ran out…

Bending the pleats takes a bit of practice and patience. For my first ones drew a number of evenly spaced lines (settled on 16 for the big soda cans, 12 for the red bull cans)around the perimeter of the can. I then used a butter knife to start the bends, pushing inwards against my fingers, then in between each of those inward bends I did the opposite making the outward creases. Then, a little at a time, went around the stove bending it more and more until it became conical enough. The problem was the pleats eventually cracked at because of the sharp bends. I then found a small diameter screwdriver and used that as a mandrel to bend the can around, and it turned out MUCH better.
https://lh4.googleusercontent.com/-z_PtAQElnK0/TuEERpZcIVI/AAAAAAAABnk/8GGr-aqlCKc/s1152/IMG_20111208_103826.jpg
https://lh3.googleusercontent.com/-sWAp2Arqr1I/TuEBc9gyOlI/AAAAAAAABnc/6VsXcC-bnyI/s1152/IMG_20111208_100033.jpg

BM

[James Marco]

Several different types of fuel. I settled on ethyl alcohol as being about the best. I also burns HEET and SLX, but failed when I tried gasoline, and WG. Kero, I did not even attempt. I named these Mercury stoves because they kind'a reminded me of the first space flight.

I was using a set of old needle nose pliers that I ground the edges off. Once they are marked, I just set and twist on the up.The down is a bit more difficult, it only bends to a bit over 90* so I bend the rest with my fingers. It goes pretty quick. about 10 minutes to make the whole stove. Cutting, it off, marking and bending.

BTW, the angle is quite important. Too steep, and it doesn't get enough oxygen. Too shallow, and it burns rich and looses a bit of efficiency. 45* is about right for a 12oz can. Anway, play with it.

The additional holes for heating the stove will make it burn quite hot. Makes a good small "point" source for heating under a cone, better than the 10-12 for fuel, not for time.

[Hikin’ Jim]

Interesting photos. It looks tricky yet doable. Hmm.

Thank you.

HJ
Adventures in Stoving

[James Marco]

Jim, This design also lets you turn off the stove (can be a bit trickey with the holes, but works with a piece of aluminum foil) and recover any remaining alcohol.

[Rusty Beaver]

Intriguing stove. I'm very interested in hearing and seeing more. Videos would be great too! (wink)

rusty

[Hikin’ Jim]

James,

About how high is your conical stove? (the one made from an aluminum can) About 4cm? And maybe 3cm wide?

HJ
Adventures in Stoving

[James Marco]

Jim,
The stove is exactly 30mm (3cm). I started about 5mm up from the can bottom.
The pleats in general should be sharper at the top(vapour outlet) and wider towards the bottom(air inlet.) The opening was around 25-26mm. Of the half dozen or so I made, some had more pleats, lower angles, fewer pleats and higher angles. I tried 1, 2 and three holes in the sides. Each burned much hotter, but lost efficiency. The one pictured has 16 pleats at 5-6mm. The 12 pleats worked as well. There was no loss of efficiency that I could detect, but it also had a couple cracked corners.

The cone was a home made aluminum one, *just* fitting around a grease pan. It was somewhat more symetrical than the one from trail designs and did not include a handle cutout. I later cut it down for a smaller stove and pot. Then tried to burn some wood in it…not too succsefully. Anyway, I got a pattern maker from the web:
http://www.pulserate.com/index.php?content=download

The pot was an expot. Heat EXchanger POT. It had 6 radial style dimples about 3/8"-1/2" deep around the bottom and dished about a half inch. This also gave about 14% improved efficiency in a Trail Designs cone with their stove…about .45oz as I remember, but, I no longer trust my memory on those tests. Without the exepot, a standard grease pot, it was about .52 or .53oz. Rand at Trail Designs has a copy of those tests, for sure. The Mercury stove got about .36 or .37 with the exepot. and cone. Good, but not good enough for the 6weeks of fuel. I like my coffee too much, I guess. Anyway this goes back almost two years.

[James Marco]

Rusty,
Well, I am a bit flattered, but you guys have seen it. I don't flutz around too much on the web. Like all ideas, it ain't worth anythin' unless somebody *uses* it. Try one, make your own tests. Everyone will use different fuels. Different pots. Different wind screens. I oulined what I do and why I think of it as a failed project. Actually, I am a bit embarassed since it was *supposed* to burn WG…design failure.

[Hikin’ Jim]

Kevin,

If you're still following this thread, do your jets "bloom?" I and a friend made something similar in scale, but the inner wall does not angle inward. However, the jets never fire. It functions as an open cup burner.

I got some good times (in terms of efficiency) this past weekend: boil in about 12 minutes, total burn time in 15 on 15ml of green denatured alcohol.

HJ
Adventures in Stoving

[Kevin Beeden]

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

[Hikin’ Jim]

Ah, that may very well be the case. I was over at a friend's house doing some stove testing. We realized that our stoves were too tall in proportion to the width of the opening. I literally had to swallow the last few mouthfuls of my drink in order for us to build the stove in the photo. We may have been a bit hasty in our technique.

I'll have to give it another go. The proportions are promising. Perhaps if I can get it to "bloom" it will burn more cleanly.

HJ
Adventures in Stoving

[al b]

When testing open well stoves, I think flame photos need to be taken with a pot over the burner, as otherwise you may get an unrepresentive long tall yellow flame(incomplete combustion):

the pot should cause turbulence, causing oxygen and fuel to mix better, hence nice blue flames (hopefully…).

[Hikin’ Jim]

Alan,

That's a good point. In the photos with a really tall flame, I've removed the pot for photographic reasons. My "real" tests are done with a pot in place. They're just not very exciting.

(yawn) Now this is a serious snoozer of a thread.

Quick! I'd better post a photo of my attractive female assistant.

HJ
Adventures in Stoving

[Ultra Magnus]

@James- Funny how you consider it a failure but I think it's a total success. Until now I only achieved those efficiencies with much harder to construct pressurized designs (does anyone remember the mini-bull designs nion?). And it's about as light as you could possibly build an alky burner at a measly 3grams.

@Kevin- I found the thread on OM about your clone and it's really impressive. As a clone of the Trail Design's Caldera Cone, I'd be willing to say it's quite an improvement- esp. the interlocking 2pc cone. that's one issue I've had with the TDCC- I really like my whole cookset to nest neatly in my pot. I don't like the way cone setups work with Heineken pots, but I'll be looking into making one like you describe for my 1.3l ti pot- and maybe looking into getting a narrower ti mug as well…

BM

[James Marco]

BM, Yeah it works real well with all sorts of alcohols. I started out to buld a high density fuel burner, though. WG was the target fuel. So, that was a failure. It always produced enough soot, except at very narrow openings that produced less heat than a candle flame. (More pleats, taller stove, means a narrower opening.) Anyway, I am glad someone found a use for it. Mercury flies again…

BTW: The wife has some beading tools, a looping beading plier, that seems to work well for making down pleats. Just pinch for the up pleats.

[Author]

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