Question on alky stoves

[stickman]

I've never used an alky stove but am thinking of swithing from my cannister stove to alcohol. One of my questions is what happens if you finish cooking and have alcohol left in the stove? I know with a Trangia you can put on the lid and hike on. But the soda can stoves don't seem to have any way of sealing up any left over alcohol. Do you have to burn it off, shake it out, or am I midding something? If you waste fuel, doesn't that soon negate the weight savings of the soda can stoves over the Trangia?

[Streamweaver]

Once you have used the stove a few times its pretty easy to guestimate how much alcohol you will need for a meal.especially if you are just boiling water. Then its just a matter of carrying something to measure the alcohol with . A regular size soda bottle cap makes a good lightweight measuring cup that holds about .25 oz and then after your water is boiled you just let it burn off and you arent wasting much fuel at all. Another good measuring cup that I recently discovered is the little plastic cups they give you pills in at the hospital . they have several measure lines on em (even drams) and hold an ounce. I made a couple stoves before that had a small drain hole on one side so after it cooled I could pour the remaining fuel back into the bottle ,it worked ok but it was kinda messy and prolly wasted more fuel than just burning some off. Even with burning that little bit of extra fuel you still save quite a bit of weight with the alcohol stoves. Streamweaver

[Spirit Walker]

To measure alcohol, I use the little plastic cup that comes with Nyquil. One cap boils enough water for two cups of coffee/tea.

[stickman]

Thanks, guys. Sounds like I just need to experiment a little.

[highway]

I tried the homebuilts but went back to the Trangia-because of their efficiency. They are more fuel efficient and can simmer, so I can cook most store-bought foods requiring longer [15 minutes or so]cooking on slow. Another plus is it has its own fuel reservoir. You just fill up your Trangia with 4 ounces denatured alcohol, light and boil, put on the simmer top for simmer and snuff out the flame when finished. When it cools screw top on. I can go for 3 days(2 1/2 days cooking) just with the 4 ounces fuel in the reservoir, without carrying an extra alcohol container.

It is heavier though. The Trangia stove and Westwind stand weigh 6.4 ounces. But I dont have to fumble with a cap and guess at an amount to pour each time I want to cook. I just unscrew top and light. Plus it just might last your lifetime, because it may never wear out-its that well built.

It does cost more-about $20 bucks is all, though. But if you want "roll do your own", the home-builts are practically free, weigh next to nothing and you can cook proudly on a stove which you yourself built from cast-off materials instead of just bought. There is a decided attraction for that for many, I see from reading this forum. I just never developed it, probably thankfully enough.

[Lilred]

I ran some tests and found that the soda-can alcohol stoves burn one ounce of alcohol for about 6 minutes. Two cups of water come to a rapid boil just under 5 minutes. I found a plastic flask at Walmart that holds sixteen ounces. It has a screw on cap and another silver cap that resembles a giant thimble. The 'thimble' is one ounce. This way I'll know exactly how much fuel I'm using up. I'll mark my gatoraide bottle at 4oz. intervals and use it for a measuring cup as well for the water.

[poison_ivy]

I used the pepsi stove I bought from antigravity gear this week for the first time and found that about an ounce of alcohol is sufficient to boil enough water for my meal and a cup of hot chocolate. I generally just let the stove burn itself out, since I brought more than enough fuel for two ounces per day. For the most part, I just eyeball how much I put into the stove.

I met another hiker along the way, who marked his soda bottle in two ounce increments, as lilredmg is suggesting. It seems like a great idea and is something I will definitely be doing.

- Ivy

[thyroid]

If you have extra fuel once you are done cooking, you could always just pour it back in your fuel bottle, however alcohol stoves are hard to blow out. You'll probably have to snuff it out.

It's probably easier to just know how much fuel you need for your cooking needs and use just enough. Small plastic prescription medicine bottles work good for measuring your fuel.

some Alcohol stoves like Cobra's stove allow you to measure the fuel with the stove itself. Check it out..

http://flappyhappy.tripod.com/cobrastove.htm

:banana :banana :banana :banana :banana :banana

[chris]

Here is a wild idea: Use your stove more than six times without measuring fuel. You'll be able to eyeball how much fuel you need, within 1/4 oz. If you want to save that 1/4 oz. of fuel, you are way too weight concious to be out hiking. Just let it burn out. I think SGT. Rock, our local stove expert, might dispute the claim that a Trangia is more efficient than a homemade stove.

If you want to simmer, build a little simmer ring. Construction is easy and free. Lots of designs out there. All it does is cut down how much oxygen gets to the stove. There isn't much reason to simmer, though: Boil water, add your packet, stir for a few minutes, eat.

[highway]

Originally posted by chris
I think SGT. Rock, our local stove expert, might dispute the claim that a Trangia is more efficient than a homemade stove.

If you want to simmer, build a little simmer ring. Construction is easy and free. Lots of designs out there. All it does is cut down how much oxygen gets to the stove. There isn't much reason to simmer, though: Boil water, add your packet, stir for a few minutes, eat.

Chris:
I sure hate to use rock's words since he is not here to confirm/deny but I have saved some e-mail correspondence between us in our arguments about stoves-me pushing the Trangia and he his own designs. But to recap, Rock did in fact agree to the greater efficiency of the Trangia and it was that efficiency which he strove to equal or beat with his own design. What he did not like about the trangia was its weight. In other words it was best for "fuel economy" but not "weight economy". The 6 ounces of the Trangia is what he objected to and was what he was striving to overcome with his own experiments & design.

As for simmering, many of the better tasting foods in the supermarkets involve more cooking time than just "heat & serve" and for them its necessary to either simmer or use Rock's "cozy" contraption which holds the heat inside the pot after boil is reached, so cooking can continue after the flame is extinguished.

Here is hoping he comes home soon and finishes his stove design!:) :banana

[chris]

I was under the impression that Rock's Ion stove is more efficient than the Trangia. Unless you buy something that takes 20 minutes of cooking (many of the beans and rice dishes), most foods really are boil, heat, and eat. Something that lists a 5-8 minute cook time (i.e, Liptons, Mac and Cheese, regular pasta) will actually cook in much less, particularly if you put the stuff in the water at the start, rather than waiting for a boil. Ramen takes 2 minutes on the boil, or add and bring up to heat. Couscous takes no cook time, just add and let it sit. Potatoes and stuffing take no time, either. Homedried foods take no cook time, just add to the water and bring up to a boil. Then let it sit.

[kank]

Sgt. Rock's Ion is more efficient than even the Trangia, at least in the testing described at his site. However, I don't believe Sgt. Rock has yet adopted the Ion as his main alcohol stove (he may not have had time for much field testing before he left for Iraq). I have not been able to duplicate Sgt. Rock's impressive results with the Ion, but my own version of the Ion is in fact my most efficient soda can stove and the stove that I use for every trip. I will note that there are a number of people that achieve Trangia-like efficiency from their soda can stoves. However, these people typically invest a fair bit of time and effort into experimenting with different stoves, burner holes (size and number), pot height, and windscreen design. Obviously, not everyone is going to be interested in doing so much work (myself included). If you dig through Sgt. Rock's (http://hikinghq.net/forum/index.php) archives in the Homemade Gear forum, you'll find this thread (http://hikinghq.net/forum/showthread.php?threadid=299) about optimizing the pepsi can stoves. If you're interested, there's also this thread (http://hikinghq.net/forum/showthread.php?threadid=479) on using isopropyl fuel and further decreasing fuel consumption.

If you require 1oz. of alcohol to boil 2 cups of water, this is fairly poor fuel efficiency for an alcohol stove. I haven't invested the effort necessary to maximize my own system's fuel efficiency and find that many people use less fuel than I do. However, I can still easily boil 2 cups of water with 20mL of methyl alcohol, which is 0.68floz. and just over 0.5oz by weight. This is field-tested performance using stream-temperature water during 3-season backpacking. I do sometimes use slightly more fuel (~22mL), just to ensure a good boil without running out of fuel. This is unnecessary for most foods, but I generally carry a few extra ounces of fuel and don't worry too much about wasting a milliliter here or there on shorter trips. If you want to improve your fuel efficiency (this can be quite important for an alcohol stove system during longer hikes), you might first try experimenting with a lower pot-to-stove height. This lengthens your boil times somewhat, but I think the efficiency is almost always worth the extra minute or two. Of course, this is totally up to the individual and I'm in no way trying to imply that you are somehow doing it "wrong" if you use an ounce per boil. It's not a competition.

In regards to Sgt. Rock's findings with the Trangia and Ion fuel efficiency comparison, I believe his most recent work on that subject can be found here (http://hikinghq.net/sgt_stove/ion_stove.html). I am not trying to attack the Trangia stove, but am trying to show that Sgt. Rock has beaten it's efficiency (75% for the Ion vs. 60% for his Trangia), at least in the kitchen ;).

I'll also mention that today's tiny canister stoves are every bit competitive with alcohol stoves in the weight department. A tweaked-out alcohol stove system consuming only 15mL or so of fuel per boil is still going to be lighter for most trips than a canister system, but the difference is typically not enough ounces to be a major factor. It mainly comes down to personal preference. For alcohol stoves that consume an ounce or so of alcohol per boil, a canister system may even be lighter for extended trips.

It is not difficult to learn how much fuel is required to reach a boil if you know roughly how much water you're trying to boil. I use the screw cap from my fuel bottle (8.5floz. water bottle) to measure fuel in 7.5mL increments or thereabouts. Many meals require less than 2 cups of water, so I can often use only 15mL to cook my meal.

1 floz = ~30mL = 0.82oz. (weight of methyl alcohol)

[chris]

The stove I use isn't a fancy one. It is the bottom 2" of a beer can with a little fiberglass in the bottom. That is it. I tried making fancier, double wall stoves with lots (or few) ports, but could never get them to work well. That may be my lack of skill, but it also may be due to trying to build stoves on the weekends after drinking a few beers. The ounce of fuel is a rough average, based on how much of my 20 oz. fuel bottle I would go through between fill ups. I pour what I think is enough fuel in and let it go. Water comes up to a boil, boils for a few minutes, and is done. At home, I did actually measure and in the nice, calm, warm conditions of my apartment, an ounce was a bit too much.

One word about cannister stoves. They certainly are light, and some models fairly cheap. I even recall seeing a few cannisters for sale in the south. But you would have a hard time finding them on something like the PCT and thus are tied to maildrops. Denatured and methyl alcohol are available almost everywhere.

[MadAussieInLondon]

Kank, i wouldnt mind trying out aarons new turbo-ii model at brasslite. i have his handmade solo stove. looks like a very smart stove!

[woodhippie]

this is a great thread......again I just want to say how much I love my home made denatured alcohol stove..just got back from the Red River Gorge and it worked great....even starting to get the feel for amount needed to boil for meal time and as important how much to place in tray for ignition which is where a lot of fuel is wasted if too much is used causing stove to " blow torch " when first lit. Anyway I've picked up some great tips from this thread....thanx.

see ya in the woods

woodhippie

[thyroid]

Good job, Woodhippie.. That's maybe a full pound you've sliced off your pack... I sometimes feel guilty for replacing my small and beautifully engineered Snowpeak Giga canister stove for something made out of 2 soda cans-- at least until I start sweating it on the uphill.... :eek:


Were you using Sgt. Rock's stove..?

:banana :banana :banana :banana :banana :banana

[SGT Rock]

I did find the Trangia to be the most efficent using a windscreen and the set up that came with it. I also found it was not the most weight efficient.

Now my Ion stove is pretty darn fuel efficient, but isn't what I consider perfected. Others have made versions of my Ion stove, but from the performance they report it sounds more like a turbo V8. But whatever that means...

(I'm about to go off in a tangent here, too much time in the Iraqi sun has me wondering since I can't hike)

See, despite the label Ion Stove, Turbo V8, whatever, they are nothing really new. They are all minor variations of the good old double wall stove. The smaller cans make them lighter and produce a tighter burn area than a soda can stove, but that isn't really much of an inovation. Somewhere back in time someone decided to make a stove from cans and no one will probably ever know his name. StoveStomper makes a system that uses a burner like man with a complete different stand - a great change, I really feel adaptations that each of us make are totally personalized to our hiking style and really defy labeling it as something like "Modified Ion Stove" or whatever. That is Stove Stomper's stove, he could call it whatever he wants.

I guess where I am going with this is if you want to try alcohol stoves, you may nail it with the first one you build, or you might be like me after a few months of one stove when it hits you "I could make this work better if it did XXX". And if you make a change and it works - Great! Please share how you did it, maybe it will work for one of us, and maybe not. But at least we are all learning.

I love this thread and I think I just rambled like a blooming idiot.

[kank]

Thanks for the input, SGT Rock. You said it pretty well and didn't ramble on nearly as much as I do! It is important to recognize that these stoves are mostly variations on a theme. It is perhaps not even the stove "design" that is the most important factor to fuel efficiency. The windscreen height, intake area, and gap around pot are all things that affect performance. The pot size is important, too. The stove must sustain an optimal burn rate for the entire system (this is somewhat adjustable by raising or lowering the pot) and this is affected by burner hole size and number and a myriad of other stove variables. There's some sweet spot in there somewhere and if you get it right the first time, everything's great. If you don't, you can sometimes make another stove exactly like the previous one in dimensions and construction technique, yet it will probably perform differently. I threw my first double-wall can stove together very quickly in an impatient fit to see how it worked. Though it leaked at first due to my failure to seal around the sides, after some leak repair it was my best full-size soda can stove to date. I took it apart to check out the dimensions and fit of the parts and then threw it away. I was then making a new one that was much more precise and fit together perfectly, so I imagined that the new one would be even better than the first. Wrong. The new stove required much nashing of teeth just to get it primed and required numerous modifications to get it working. Some of my newer stove made from smaller cans have worked pretty nicely, but none have equaled the beginner's luck that I had with the one I threw away. The moral of this story is that being a perfectionist when making your stove may be a detriment rather than a benefit :).

Pour alcohol in a metal cup, light it, and it will burn just fine. The double-walls, fiberglass wicks, and what not are all mainly just ways to improve vaporization rate and therefore burn rate (some have shown through testing that the wicks do improve fuel efficiency, but I haven't figured out why this happens). One reason the trangia is so efficient is because it's slow. A slower burn rate slows down the hot air exhaust so less heat escapes around the pot (the main reason gas stoves are so inefficient). Alcohol stove systems usually exhaust only warm air around the pot, while gas stove systems can exhaust very hot air. This is heat that is not going into your meal and can be considered waste unless you happen to need a good hand warmer ;). I often do.

[woodhippie]

hey thyroid

Yes I made my stove as close to the instructions of ole Sarge as I could. The main difference is I placed 16 holes instead of 18 in the burner....blame that on 30 years since I took Geometry.anyway it works great. For a wind screen I used a sheet of stainless shim material I found at work......it is light...wont rust and rolls up around the fuel bottle in a neat little package..........another modification I made was to use threaded rod.....1/8 dia I think for the support for the pot. It seems to grip the sides to a point that it really holds the wind screen together very well. As far as the holes for air in the wind screen I placed mine where they would be just below the edge of the support can. It will be interesting to see how this works this winter.

see ya in the woods

woodhippie

[Youngblood]

I found a web site about wood stove efficiency that has some interesting pointers about stoves in general. Take a look:

http://tinyurl.com/nr76

I think a lot of alcohol stove efficiency is in the pan size/burner size as well as ground reflector, wind screen fit, intake air ports and stove to pan distance. Also, it don't hurt to be able to extinuish the stove and use the remaining fuel at another time. I use mutliple burners (tea light candle tins) and I haven't seen an alcohol stove that I like better. I splash a little alcohol on my ground reflector/pre-heat pan and it lights up very easy. I can put different amounts of alcohol in each burner (I usually use two except in sub-freezing weather when I sometimes use three or in the heat of the summer I may just use one) to reach a quick boil and then simmer. When I am done, I can blow out the one remaining lit burner and it is cool enough in about 10 seconds to pick up and pour the unused fuel back into my fuel bottle. By themselves a tea light candle tin is a pretty wimpy excuse for a stove, but with the right stove system they work pretty darn well.

Youngblood