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First alcohol stove
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John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: Re: Second boil - Great at first, but then... on 03/09/2013 23:59:59 MST Print View

Tyler,

"What can I learn from this?"

Does your stove and your cook pot form a "seal" where they meet? If they do you could be over pressurizing the stove's jets as everything heats up.

Can you increase the circumference of your windscreen so that the gap between the cook pot and the windscreen is larger?

Some of the bottle stoves use raised dimples where the cook pot rests on top of the stove. Does your stove have these raised dimples? If not try a burn with a "triangle" of SS wire between your cook pot and your stove. .020" or .030" SS wire should be a large enough diameter for a trial run. This may help in reducing some of the pressure at the jets.

If it does then you have to decide if you want to "dimple" the top of your stove. ;-?

In the picture below there is an example of what I am describing.

Dimpled top aluminum bottle stove

Look closely at the top left of the stove in the picture for an example of the dimpled top on a bottle stove. There are three dimples spaced equally around the top where the cook pot rests.

Note:
The stove in the picture is made from a 6 oz bottle but the principle can be applied to a 12 oz bottle stove.

I would think that you could accomplish the same thing by using a round file and "cutting" 3 reverse dimples into the stove's top rim being careful not to cut them completely through the coped rim. ;-?

This modification would be irreversible!

Make each test burn changing only one thing at a time.

Party On,

Newton

Edited by Newton on 03/10/2013 04:47:37 MDT.

Tyler Miller
(FightingTheTide) - F - M

Locale: Southeast
Re: Re: Re: Second boil - Great at first, but then... on 03/10/2013 07:01:20 MDT Print View

I'll see if I can use a paperclip or something to keep the pressure from building. I was wondering if that was the issue. Only one way to tell. R&D tonight!

One thing I noticed is there is soot on the windscreen, but not on the pot or the stove. It's predominantly on the side where the flames were tall and orange. I'll take that to mean the fuel wasn't burning as clean as it should have.
soot

And no dimples on my version. I might add those later depending on what I find tonight.

Bottlestove

Edited by FightingTheTide on 03/10/2013 07:12:03 MDT.

Jon Fong
(jonfong) - F - M

Locale: FLAT CAT GEAR
Re: Re: Re: Re: Second boil - Great at first, but then... on 03/10/2013 17:14:18 MDT Print View

1)I suspect that you are getting yellow flames is that the ethanol content may be too high. Look up the MSDS online to check the percentages. On solution is to add a little water to your fuel to calm it down a bit.

2)Fuel measurements. 1 tablespoon = ½ ounce of fuel. 1 teaspoon -1/6 ounce of fuel. A typical bottle stove like that will use ¾ ounce to boil 2 cups of water.

3)For grins, you can take a picture of the stove burning with the windscreen (showing the yellow tips and then remove the windscreen and look at the flames. If you see a big difference, then there is probably a windscreen/stove/mug interaction

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: Re: Second boil - Great at first, but then... on 03/10/2013 17:25:12 MDT Print View

What is the metal surface with the diamond pattern? That might be such a reflective surface that it is changing the stove performance. Normally the burner is sitting on the ground which is not so reflective.

--B.G.--

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Caldera Cone on 03/10/2013 19:45:06 MDT Print View

I think that for THE best efficiency you should get a Caldera Cone stove.

I have not found anything close to a Caldera Cone for fuel-to-heat ratio with alcohol, ESBIT or wood.

Robert Kelly
(QiWiz) - MLife

Locale: UL gear @ QiWiz.net
What an interesting thread . . . on 03/10/2013 20:31:51 MDT Print View

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
(brucky) - F

Locale: Central Cal
Re: What an interesting thread . . . on 03/10/2013 21:10:33 MDT Print View

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
(Newton) - MLife

Locale: Southeastern Louisiana
Re: Second boil - Great at first, but then... on 03/11/2013 04:47:37 MDT Print View

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
(jonfong) - F - M

Locale: FLAT CAT GEAR
soot and yellow tips on your alcohol stove on 03/11/2013 08:56:12 MDT Print View

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
(zelph) - MLife

Locale: www.bplite.com
Take a step back on 03/11/2013 10:38:44 MDT Print View

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

Harald Hope
(hhope) - M

Locale: East Bay
some data on 03/11/2013 13:31:45 MDT Print View

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.

Edited by hhope on 03/11/2013 13:38:36 MDT.

Robert Kelly
(QiWiz) - MLife

Locale: UL gear @ QiWiz.net
Some results of testing FWIW on 03/12/2013 10:50:08 MDT Print View

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.

Edited by QiWiz on 03/12/2013 10:55:38 MDT.

Daniel Fish
(daniel@fishfamilypdx.com)

Locale: PDX
... on 03/12/2013 11:41:07 MDT Print View

...

Edited by daniel@fishfamilypdx.com on 06/23/2013 12:01:29 MDT.

Tyler Miller
(FightingTheTide) - F - M

Locale: Southeast
Re: Some results of testing FWIW on 03/12/2013 11:47:46 MDT Print View

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
(daniel@fishfamilypdx.com)

Locale: PDX
... on 03/12/2013 14:40:39 MDT Print View

...

Edited by daniel@fishfamilypdx.com on 06/23/2013 11:59:50 MDT.

Ben 2 World
(ben2world) - MLife

Locale: So Cal
Re: Carbon Monoxide Testing on Alcohol Stoves on 03/12/2013 14:42:49 MDT Print View

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
(daniel@fishfamilypdx.com)

Locale: PDX
... on 03/12/2013 14:46:16 MDT Print View

...

Edited by daniel@fishfamilypdx.com on 06/23/2013 11:58:06 MDT.

Tyler Miller
(FightingTheTide) - F - M

Locale: Southeast
Still the same results - flames up the side... on 03/22/2013 20:44:29 MDT Print View

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.
Flames

Original White Box Stove
Original White Box Stove

Edited by FightingTheTide on 03/22/2013 21:36:39 MDT.

Jon Fong
(jonfong) - F - M

Locale: FLAT CAT GEAR
Re: Still the same results - flames up the side... on 03/22/2013 21:28:24 MDT Print View

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

Edited by jonfong on 03/22/2013 21:29:02 MDT.

Tyler Miller
(FightingTheTide) - F - M

Locale: Southeast
Re: Re: Still the same results - flames up the side... on 03/22/2013 21:37:20 MDT Print View

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...

Edited by FightingTheTide on 03/22/2013 21:39:34 MDT.