First alcohol stove

[Robert Kelly]

The way I think about bottlestoves, including the one I sell, is that they have advantages of [1] being durable (I can literally stand on mine with all of 200 lbs), [2] serving as a pot stand as well as a burner, and [3] heating water quickly. Their potential disadvantage is that they are not as efficient in terms of fuel used for a given amount of water boiled as some other stoves.

So whether a bottlestove is the stove for you depends on your priorities. There are lighter, more efficient, slower stoves. There are also heavier, less efficient, slower stoves. The one I sell weighs an ounce.

I am fascinated by the discussion around dimples to raise the pot a wee bit so that the stove is not as pressurized. I will have to test this idea with some thin SS wire spacers as suggested and see. I have no idea if this will get Tyler's setup to burn less fiercely and more slowly.

I recommend putting the alcohol in the stove that you need for a given burn, by measuring what you put in, rather than trying to recover unburnt fuel. I know some will disagree on this point, but fuel recovery I find not worth the trouble if I measure well.

I would think a wider pot than what Tyler has now would have less flames up the side, but I think you would have to test whether that improved efficiency or not. For small volumes of water, maybe; for half a pot or more, maybe not enough to notice.

[Brandon Guy]

Check out the stoves from mini bull design for a good dimpling example

https://www.minibulldesign.com/productcart/pc/viewPrd.asp?idproduct=54&idcategory=2

If memory services me he put the dimples on after some overpressurization problems happened with some customers, flaming way out of control and stuff.

[John Donewar]

Tyler,

" At first, the flames were much smaller and seemed to barely even come around the side of the pot. I was thinking I had this thing figured out. And then about half way into the boil, the flames started spilling up the sides."

Here is where a budding new "Stovie" begins to learn about the love hate relationship between the Stovie and his stove(s). ;-)

It definitely seems to me that the stove is suffering from over pressurization. The question is whether or not the pressure is increasing due to overheating, too efficient a seal at the base of the cook pot or too high a BTU content of the fuel being used.

The reflective surface underneath the stove and cook pot could be adding to the over heating / pressurization problem as Bob suggested.

1.) Try the wire spacer between the cook pot and the stove.

2.) Try using a paver / step stone under the stove instead of the metal surface.

3.) If possible try a wider gap between the windscreen and the cook pot.

4.) Try a less volatile fuel as Jon suggested.

I also wonder if enlarging the jets or adding another row of the same size jets above the existing row of jets would in effect raise the flame and lower the pressure.

Caution

This is another of those irreversible modifications with no guarantee of success!

Questions:

What is the temperature of the area where you are doing your tests?

Is it similar to the temperature you'll encounter on the trail?

Do you plan on using a reflective surface / ground shield with the stove on the trail?

Good luck and please report back with your findings.

Party On,

Newton

[Jon Fong / Flat Cat Gear]

If memory serves me correctly, the reason for the dimples is to allow the inner chamber of the stove to vent. When burning alcohol one of the by-product produced is water. The water can condense on the pot and migrate to the stove pot interface. If enough water forms, it can wick around the stove/ pot interface forming a capillary seal. This can allow the pressure to build up and worst case, push fuel out of the nozzles. Adding a shim/dimple seems to have resolved the problem.
I would encourage you to take a step back and fully test your stove without a windscreen. If you are producing soot and yellow tipped flames, you have a problem that needs to be solved. Best regards – Jon

[Dan Yeruski]

I would encourage you to take a step back and fully test your stove without a windscreen as Jon has suggested.

[Harald Hope]

Crown® Denatured Alcohol NEXT

CONTAINS:
95-100%
ETHANOL (64-17-5)[200-578-6],
0 -10%
ISOPROPANOL (67-63-0)[200-661-7]
Number in parentheses is CAS #, number in brackets is European EC

msds

I'd say it's the isopropanol that is causing the yellowing and sooting if present. I saw the same with enrg fuel, which burned so sooty as to be unusable. As with other msds I am astounded at the arithmetic, doesn't anyone actually check a msds to make sure it's possible? (if eth is 95-100% then isoprop can be no more than 5%, but if eth = 100%, then it's not denatured…) My conclusion, as with enrg, is that they are lying about the quality ingredient, and that it's actually probably 90% ethanol and 10% min isopropanol, which is where the yellow comes from.

enrg used isopropyl alcohol, not sure what the burning difference, if any, is between the two iso types.

The flames shooting up the sides means it's getting too hot, I have been testing that recently, it's vaporizing too quickly, which also results in incomplete, ie, inefficient, burns, though fast. Make sure to use a measuring device when testing to see what the actual capacity is, some people here suggest medicine measuring cups, if you can find them, but those little plastic containers that some restaurants etc give samples in are also good, they are about 1 oz or so big, if you then carefully mark them for the actual amounts (hint if you go to a pharmacy they may have irrigation or oral irrigation syringes which let you create the measurements with precision.)

I find it difficult to get 2 cup (500ml) boils consistently with less than 17.5 ml fuel at normal temps, but with that much, it always boils at normal temp. If you use any kind of cone, actually it doesn't even need to be cone, all it has to do is funnel the heat towards the top and close it off, I have found it makes very little difference how you do that, even with an open front on the windscreen, as long as it's conical, it's far more efficient, but also more of a pain to use and pack. I believe just tabbing the top of the screen and bending them in as Jon Fong does on his flat cat systems screens is all you need to do to get that cone heat efficiency.

You should be able to get a fine burn with a supercat stove, just the fancy feast can with two rows of holes punched in, about the easiest stove out there to make, not quite as efficient but I think your pot is wide enough to use it.

Also keep in mind, there's a major drop in efficiency if the stove is in direct contact with the ground, something both the penny stove and cat can stove creators were aware of, and provided a way to make a base, there, the penny is the easiest base by far to make, and it works very well to insulate the stove from the ground. I noticed this when testing some time ago, inside, or on a piece of wood it worked fine, but with particularly one cat can design, with fewer holes, when it was put on the ground directly on a chilly night, it wouldn't even light. So a base is another frequently overlooked feature of stoves. Workbench testing isn't a very good substitute for testing outside in cold/wind etc, outside tests show much better what the stove will really do when you use it outside.

For testing purposes, if you are doing it outside, the slx basic stuff burns cleaner but not as hot as the ethanol you are using, but make sure NOT to burn that inside, it's very dirty and toxic in terms of its actual ingredients. But it's cheap and easy to find, so it's a good testing fuel.

[Robert Kelly]

I did a burn in which I compared having and not having a thin stainless steel wire shim between the bottlestove and my pot. Video: http://youtu.be/PgRnG0Eoaa8

It did seem as though without the shim, a seal with moisture did develop and larger flames came up the side of the pot, possibly indicating a faster fuel consumption. I did not see yellow flames. With the shim, the flames seemed more subdued. This makes me think that a thin shim (or dimples) are a reasonable mod, especially for smaller diameter pots. The wire I used was thinner than a paperclip, really just enough to make sure there was no complete seal. I suspect that a paperclip might work just as well, and possibly better.

My fuel was HEET (yellow bottle). I was using a 900 ml Evernew Ti Mug Pot, which is more tall than squat and is about 4 inches in diameter (http://www.evernewamerica.com/ECA267.htm), with one of my medium titanium windscreens, with the usual slots cut in the bottom on half of the circumference. The bottlestove was outdoors on a stone step with no reflective material underneath.

[Daniel Fish]

…

[Tyler Miller]

You seem to have found exactly what I found. The differences for me are my fuel, pot, ambient temp, metal surface underneath, and my windscreen has a tighter fit around the pot than yours does. I've been busy the last few days, so no testing here yet, but I'll do a test with a paperclip shim to see what I find…maybe tonight or tomorrow.

As for the metal surface, it's my old truck box on my back porch. I'l have to take my stove to the sidewalk for my next test. Didn't even think about that variable. I'm sure it has something to do with the tall flames but my guess is not as much of a difference as the seal forming between the pot and the stove.

[Daniel Fish]

…

[EndoftheTrail]

To me, carbon monoxide is a non issue. NO ONE should ever cook inside a tent — esp. with an alky stove whose flames can flare up unpredictably.

[Daniel Fish]

…

[Tyler Miller]

I did more testing tonight. This time I still had flames spill up (quite violently at times) but no boil.

To get separation between the stove and pot, I took a paperclip and made it into a useable shape. The weather was about 45* and the wind was light. I tried an original White Box stove and a Bottlestove once each. Both times, I used 4.5 teaspoons (.75 oz) of Crown's Green Denatured Alcohol and 2 cups of cold water from the faucet. I also took it to the sidewalk…if you remember from the first test, I put the stove on my metal truck box, which probably increased the efficiency.

Any idea what I am doing wrong? I'm almost to the point of just buying a Caldera Cone.

It wasn't always this bad, but the flames were constant up the sides of the pot…generally down-wind when there was a gust.

Original White Box Stove

[Jon Fong / Flat Cat Gear]

1 tablespoon = 1/2 ounce, so you added 2 1/4 oz. of fuel. You probably overfilled the stove. Add 2 tablespoons and re-run the test in a calm area without the windscreen. Best regards – Jon

[Tyler Miller]

My bad, I meant to say teaspoons. I used 2.5 tsp per burn.

What would calm conditions show me? Don't I need this to work in any condition? Or are you suggesting this so I can get a better idea of what it *should* look like?

I'm seriously eyeing a Caldera-H…if they were only in stock…

[Piney]

This is exactly what my bottle stove was doing when I was experimenting with isopropyl blends. Out of control yellow sooty flame and super quick burn times, sometimes so quick it never reached boil. I would try different fuel.

[John Donewar]

Tyler,

From what I see in your picture you have your windscreen set down on the concrete. Also it appears that the draft holes for combustion air are on top instead of the bottom.

Your stove is searching and hunting for combustion air that it can only find above your windscreen.

I believe that your stove is overheating and thus going into an over pressurized state.

Turn your windscreen over and try raising it like you did earlier with the binder clips. I can't tell from the picture whether or not you have the wire spacer between the cook pot and the stove(s).

Have you tried using HEET in the yellow bottle as your fuel?

Party On,

Newton

[Tyler Miller]

Oh man, I didn't even realize I had my windscreen upside down. Freshman mistake.

Thanks! I'll do it again tonight with the windscreen in the proper position. As for the clips that lifted the screen…that was just for an experiment. I'm not taking those on the trail, so I'd like to find a trail-worthy setup.

And should I add some water to the fuel? I'll try to get my hands on some yellow HEET to try that as well.
http://www.backpackinglight.com/cgi-bin/backpackinglight/alcohol_fuels_part_two#.UU28Y1vwJD0

Oh, and I think I did have the windscreen in the proper position for my first burn last night. So I really do think the windscreen wasn't the major issue…but definitely an issue.

[John Donewar]

Hi Tyler,

Get some inexpensive aluminum flashing or some heavy duty aluminum foil for experimentation purposes. Here is a picture of how you can achieve the same effect without the clips.

Dan a.k.a. Zelph made a video showing how raising the windscreen 1/2" to 3/4" of off the ground or in your case the side walk helps to stabilize the flame.

http://www.youtube.com/watch?v=a7mb-DU2sWY

As you will hear in Zelph's narration of his video it appears that even having the holes in the bottom doesn't work as well as elevating the windscreen.

"And should I add some water to the fuel?"

Give it a try and see if it helps. Jon Fong offered this same suggestion earlier in this thread. Look for the post directly under the picture of your bottle stove.

I'm not sure of the ratio for dilution of the fuel. I'd try 5% and then maybe 10% water just for grins to see what it does for the performance of the stove.

Dan (Zelph) and Jon are really good guys and will freely answer questions and give advice on alcohol stoves. I lean heavily on their advice. ;-)

Something in the back of my mind keeps saying dimples or wire spacer between the cook pot and the stove. ;-?

This may reduce what I suspect is an over-pressurization and over-heating related problem.

Party On,

Newton

[Tyler Miller]

Wow, so much great information to take in at once. I know I've overlooked a good bit of advice, but it wasn't intentional. Here's what my next set of tests will all look like with the Bottlestove and White Box Stove:

-2 cups of cold water from the tap
-no windscreen (and hopefully no wind outside)
-2 types of fuel: HEET (yellow) and Denatured Alcohol
—with the denatured alky, I'll mix it with water…first with 5%, then 10%, and then more if it seems to be yeilding better efficiency as the water content increases

Question on adding water – do I add the same amount of alcohol, and then add the water? Or make a mixture that reflects the same amount of "fuel"? For instance, do I add 1oz of alcohol + .05 oz of water? Or make a mixture of alcohol and water that totals 1 oz?

And THEN I'll add a windscreen. I might take some wire cutters to it to see if I can make my own "risers" to elevate the windscreen about 1/2" to 3/4".

THANK YOU ALL for the help. I'm not done yet, but so grateful for the time put into helping me so far.

[John Donewar]

Tyler,

"Question on adding water – do I add the same amount of alcohol, and then add the water? Or make a mixture that reflects the same amount of "fuel"? For instance, do I add 1oz of alcohol + .05 oz of water? Or make a mixture of alcohol and water that totals 1 oz?"

Keep these factors in mind.

1.) What is the total fuel capacity of your stove. You don't want to fill it with more fuel/water mix than it can hold using just alcohol. If you do when the fuel vaporizes and builds pressure liquid fuel/water mix will be forced out of the jets.

2.) Depending on the water temperature and ambient temperature you really only want enough fuel to achieve a rolling boil and a flame out very soon thereafter. Colder water and colder ambient temperatures will demand more fuel and longer burns

3.) Don't get stuck on a particular fuel charge volume. Determine what works for you and your setup within the parameters mentioned in #1 and #2.

On my last outing I used a predetermined fuel charge that boiled water for me during testing at 70 degrees F and only got hot water because the ambient temperature was in the middle 50s and the water colder than that temperature. It was sufficient for my purposes of re-hydrating a Mountain House dehydrated meal but never achieved a boil.

I was using carried water not gathered and treated water in the example above as it was an overnighter and I had packed in my water.

Caution:

On the trail if you are "treating" gathered water by boiling by all means you want to at least achieve a boil for 1 or 2 minutes. Then allow it to cool on its own if you are using it for drinking.

I carry a pre-filter and use MicroPur tablets for gathered water treatment. ;-)

BTW Don't cut your Ti windscreen until you are sure that you are getting exactly what you want and need!

Party On,

Newton

[Bob Gross]

Tyler, let's be very sure about this. You aren't trying to burn white gas, are you?

–B.G.–

[Tyler Miller]

Nope, it's Crown NEXT Denatured Alcohol which is 95-100% Ethanol and 0 -10% Isopropanol, per MSDS.

Good question though.

[Tyler Miller]

Interesting notes per bottlestoves.com: "This is a pot pressurized stove. Once primed, it must be covered with a pot to burn properly."

So does this mean adding a paperclip or dimples would then defeat the purpose of this stove? Not sure.

Thanks Newton. I won't cut the windscreen…just yet. I'm going to try variations of these tests tonight (not too different than what I said above)

No windscreen, 1oz of fuel
1) 100% alcohol, 1oz total
2) 5% water, 95% alcohol, 1oz total
3) 10% water, 90% alcohol, 1oz total

Raised windscreen, 1oz of fuel
1) 100% alcohol, 1oz total
2) 5% water, 95% alcohol, 1oz total
3) 10% water, 90% alcohol, 1oz total

And I plan on treating water with Aquamira, but I remember from my Scouting days that you need 2 minutes of a rolling boil to effectively treat water on the trail. Once at Phimont, we even double-filtered and used iodine when getting water from a murky puddle beside a highway…be prepared, right?

[Bob Gross]

I have an alcohol burner very similar to this.

If you left the top completely open while burning, then a good deal of the alcohol will simply burn out of the top opening, and it won't be very efficient.

If you leave the top completely open for 30 seconds or so (for blooming) after lighting, and then if you cover the top completely with a metal cook pot, the burning alcohol forces its vapors out of the side jets, and that is what makes the efficient burn. This is the normal operation for a so-called low pressure side jet burner.

Now, if you had something unexpected occur, like from way too much alcohol or side jets that are too small or too few, the pressure will build up too much. It still burns great, but it might be too hot and force the side jet flames out too violently.

If that over-pressurization happened, then you would want to vent off a little of that pressure to bring it back to normal. You could do that by making the cook pot top seal leaky, or by drilling more side jets, or by making the side jets larger. If you purchased the burner, then the side jets are likely to be correct already. You could also do it by cooling off the base of the burner, but that isn't very convenient. You could also reduce the pressure by introducing a small amount of water to the alcohol, but if you get too much water in there, it will be inefficient.

I've never had one lick of trouble like this with any of my alcohol burners.

Due to the way that a low pressure side jet burner forces the flames outward, and if it shoots out too wide for a narrow cook pot, some people prefer an open top alcohol burner since the flames go upward more. It is easier to build, cheaper to buy, lighter to carry, but less efficient on fuel.

–B.G.–

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