Tealight Stove Problems

[M B]

Its a stove. The only difference is it has one big hole instead of a bunch of little ones. It uses heat transferred back to the cup to heat and boil the fuel. It might appear simplistic, but that is its elegance. What is really going on is as complex as in any other stove.

It also works very well with small pots. And is super easy to fill, light, no priming needed to aggravate you, easy to monitor fuel level during burn, super easy to simmer, super easy to snuff out. Super easy to make and super cheap to boot. Oh yeah, its super light. Cup, windscreen, and wire fabric support weigh 1.03 oz, and fit in the pot with oodles of room to spare.

Yeah I know, its heavy. But the windscreen is about .6 oz of that, I went overboard on it.

It is an A++ in the world of stoves for small pots to me.

I re-did boil tests in my kitchen with the Klean strip Green denatured alcohol. This is ~95% ethanol, ~5% methanol, trace other crud. Wow, it heats. I did the math and figured it would be at least 11% better than the SLX, and it was . It cut boil time for a full, vigorous rolling boil to 8:15 for 2 cups starting at 71F. On 0.5 oz it boiled for additional 2 min without restricting to a simmer. That would provide enough extra for it to work outside, or with cooler water on 0.5 oz .

The downside is that the Klean strip Green DOES SOOT THE POT a bit. Even a small amt of varnish looking buildup on pot bottom. Might be tolerable, my calcs say it has even ~5% more heat value than everclear. (the 5% water in everclear has no heat value and a high latent heat and sensible heat capacity)

[M B]

after playing with the klean strip green denatured alcohol more, some interesting results.

You can reduce the sooting by moving the cup closer to the pot ( i tried 4 different locations, 1/8" apart.)

My original 1/8" spacer beneath the cup provided the fastest heatups, moderate sooting
no spacer provided most sooting, slightly slower heating
1/4" spacer provided less sooting than 1/8, slightly slower heating
last was done on 3/8" spacer beneath the cup, virtually no sooting, but slower time to boil~9:15 vs 8:15 best. Caveat this was with 0.4 oz, it went out just as reached rolling.

It was easy to see that the orangeness of flame front went away as the cup was moved closer to pot. Also the flames actually went up side of pot less, opposite of what normally happened using SLX.

So my result is to get the benefit of faster heating with the 95% green alcohol, you have to live with some sooting and varnish of pot bottom. Worth it? not really.

As someone once said "If you are in such a hurry , why are you walking?"

[Terry Trimble]

Have you thought of making it like a alotoid stove. Buying some Miracle grow Perlite from home depot and filling the tea light to top edge with perlite and cutting a stainless steel screen to fit the tea light to hold the perlite in the tea lite. You will get a more efficient stove and burn with a blue flame that burns longer and will boil the water.
This might solve your problem.If weight is a issue perilite weigh hardly anything. I could not find stainless steel mesh so I bought a hand held cheap strainer and cut the mesh out of it to size.
Terry

[James Byrnes]

B.G. The boil times go down when I'm at 8 to 10 thousand ft. 8.3 min to boil. I also need to insulate the bottom of the stove to prevent heat loss to ground (usually a flat rock). This year I plan to also use a foil ground reflector. Also plan to experiment with a double wind screen.

[Bob Gross]

I'm sure lots of us have used ground reflectors of one sort or another. Aluminum foil works fine. I also have some house wrap paper to try, but it is not Tyvek. It is heavier than Tyvek, and it is aluminized on both sides, but it is not thick like Reflectix.

I do most of my trail cooking at 8 to 11 thousand feet, but I am too cold or impatient to sit around for a long time waiting for the pot to boil. That's why I usually have some butane burner instead of alcohol.

–B.G.–

[Daniel Fosse]

I tried many times to get a tea light stove to work. It never did until last night. I decided to try it again because of this thread. I'm at around 500ft, I think. The optimum burner to pot distance seems to be around 1.5in. I got a rolling boil two times. The water boiled at exactly the same same time the fuel ran out both times. I didn't measure the temp of the starting water and it was about 60F outside where I tested. No ground reflector and an aluminium windscreen. My methods were not scientific.

I may give it a go on in the woods. I only rehydrate food in bag so rolling boil or close to it should be fine.

Though it will be hard to get me to give up the simplicity of Esbit.

[Bob Gross]

Daniel:
1. What are you using for alcohol fuel, exactly?
2. What are you using for a cook pot? What is its bottom diameter?
3. How much water are you trying to boil? About 16 oz is typical.
4. Are you using a wind screen with cool air vents at the bottom?

–B.G.–

[Daniel Fosse]

The fuel is branded Sunneyside, it's denatured alcohol from th ehardware store. It's very sooty.

My pot in this test is a Snow Peak 600.

16oz is my water volume. I eat a lot of Mountain House.

My wind screen is made from aluminimu flashing. I don't know the thickness. The screen fits in the pot and is about 16inx3.5in at .7oz. There are holes (2 rows) made from a 1/4in paper punch around the entire perimiter of the bottom of the screen. There are about 9 holes on upposing sides of the scren up the height for placing tent stakes across to adjust the pot height.

The extra holes for pegs will likely be eliminated when I make my Ti windscreen. I just ordered some Ti foil from Ti Goat. I'm going to make tent stake holes at the 1.5in height for the tea light and esbit burners.

By the way, I am going to make a ghram cracker type platform with the excess foil. Are there any patterns out there?

[Bob Gross]

That denatured alcohol is popular. However, if you get very sooty results, then maybe it is not getting enough air. You might try another alcohol product, just to see if it has any effect. Maybe insulate the tealight cup from the cold ground or use a piece of aluminum foil.

I don't know the diameter of your cook pot or the windscreen around it. The metal thickness of the aluminum flashing is not important. However, it needs to fit around the cook pot with a space for hot air to move up. There should be at least one finger wide of a space all around. That is somewhere around 0.5, 0.6, 0.7 inch.

I guess you are using all of the extra holes for pegs to hold your cook pot to a certain height. What you might try is to eliminate all of those excess holes for your next windscreen, and just have a row of holes around the ground for cold air intake. Temporarily you can use something else to hold your cook pot to a proper height while you figure out that exact number. Then you can apply one set of holes to your final windscreen. If you have too many excess holes up high, then they let out too much hot air or else let in too much cool air.

–B.G.–

[M B]

The sunnyside stuff is reputed to be crap. tons of water also.

The SLX seems to be the cleanest burning denatured Ive found. Fairly good all around.

My optimum cup-to-pot distances are more like 1-1.25" for the little tealight and a snowpeak 600. Keep the windscreen tight, I like ~1/2" gap between ends on downwind side air in, and 1/4"-3/8" all around at top. As long as the flame isnt orange, you have enough air. Too much air supply and it will cool the flame. Definitely use insulation under it, it will really slow the heat output if you dont, it cools the cup. If you dont have enough fuel capacity, extend the lip up with a bit of foil tape (muffler tape, furnace tape,etc.

Given the fun I had with the little tealight and my snowpeak 600, I bought some big ones today at Walmart, they hold about 2 fl oz fuel. I figured this would be good for my grease pot, which is used for boiling 4 cups water. Basically, 1.3 fl oz of fuel will boil 4 cups in 9:30 and will boil until 12:00. With a slight modification to increase the heat into the cup (some metal sticking up to speed up the vaporization rate at start), I got 4 cups to rolling boil in 8:45 on 1.16 fl oz (0.96 oz) of SLX. Beat my pepsi stove on time and fuel, and beat the supercat on fuel for sure, about tied it for the time. Went out about 15 sec after though. 68F water, 68F outside temp (done outside, not in kitchen), and at sea level.

[Daniel Fosse]

OK, my Ti foil should be in any day now. I'm going to cut it for my SP600. Traditionally I make a buckle latch on my aluminium flashing screens. The screen has an extension with a folded over section which hooks in to a slit on the other side. This is a very sturdy design but requires an extra 1-2 inches of screen.

What kind of latches does anyone suggest? The under/over slits seem the simplest but look delicate, or prone to tearing.

The SP600 can accomidate a 3.5in tall screen. In my tests the optimum pot height for Esbit and the tea light is somewhere between 1.25-1.5 in. I think my peg holes will be in that area.

[bj bretzke]

I was told that denatured alcohol has a lot of crap in it besides the alcohol to keep people from consuming it. I have had the best luck with 100% methanol. One thing to keep in mind is that 100% alcohol does not remain at 100% due to alc. ability to absorb water. If not completely sealed it has a very short fuel shelf life. At the shop we use it for cutting laminated glass and buy it in five gallon jugs. We sometimes end up throwing a half gallon away because it won't burn. (Kind of makes me wonder about the feasibility of ethanol auto fuel) Well, just my two cents.

BJ

[James Marco]

"I was told that denatured alcohol has a lot of crap in it besides the alcohol to keep people from consuming it. I have had the best luck with 100% methanol. One thing to keep in mind is that 100% alcohol does not remain at 100% due to alc. ability to absorb water."

I believe SLX is a mixture of industrial ethenol and methanol. Both burn. Some of the cheaper stuff has mineral salts added in. Some has benzene, etc… Use only denatured alcohol that says suitable as a marine fuel or has a similar labeling.

Yes, alcohol is hygroscopic, ie it will absorb water. This is especially true for "Pure" alcohols…ie, lab grade. This is only to a percentage, depending on
the type of alcohol, though. At that point, the vapour pressures are about even and it will not pick up much more without help. This is why they use it to clear fuel lines of ice in winters. It will disolve the ice into itself. (They used to use it as antifreeze, too.)

Water in the fuel, will cause it to soot. As will improper fuels (isopropinol or rubbing alcohol is a good example.)

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