View Full Version : Questions for soda can stove gurus
grrickar
03-11-2005, 14:14
I finally broke down and went to my shop to make some soda can stoves. I have an Optimus Crux stove that I bought and will likely use for my section hiking, but I found that an alcohol stove will easily fit in a small mug, so I can keep it outside my pack for heating up a cup of soup or cider without digging the canister stove out (which nests inside a larger cookset).
I had some issues making them, and it took me about 3-4 stoves before I got decent at it. I found that at first when I would fit the stove halves together, I'd rip open the bottom half. I started cutting notches in the top half instead of just slits, and that seems to work a bit better, but then I found that if I just cut slits, but made them diagonally like this " / / /" when I put the halves together they fit really tight, and the best part, the bottom can half would not split. I have no leaks and did not even have to use muffler tape or anything.
Now for the questions:
I did not use any insulation between the inner wall, and the stoves work fine. What does adding the insulation buy you? I found that it took about 10 seconds for the flame to start coming out of the holes without a pot on top, so my thinking is that insulation may speed that up some?
What is the ideal height for a soda can stove? My heights varied, and the higher the stove the slower and longer burning they appeared to be. The flame height is lower with a taller stove. The shorter stoves were like a rocket, they burn hot and fast.
I plan to do some tests this weekend on boil times. It's not going to be too cold here, but I can at least get a comparison between my cannister stove, my liquid fuel stove and the alcohol stove.
wrt to insulation in between the inner and outer walls - the theory is that the insulation will wick most of the alcohol into the space between the walls and thus reduce the amount of alcohol burned from the central opening. The reason for wanting most of the fuel to burn through the "jets" is another theory that the heat transfer to the pot is more efficient with the jets than with the open flame. These theories are not universally accepted but many people believe them.
WRT the height of the stove - I think what is happening here is that the taller stove has the flame further away from the fuel reservior and as a result the alcohol in the reservior does not boil as fast as it does when the flame is nearer such as in the case of the shorter stove - the faster the alcohol boils the bigger flame etc.
SGT Rock
03-11-2005, 15:46
Don't forget to build a windscreen.
As to stove height, well that can be different for a lot of reasons, I basically look at flame pattern for the stove I am building. If you want a fast heating stove and you are not too worried about fuel usage, go for a flame color of yellow where the pot and flame meet. If you want a fuel efficient stove and don't care about speed, then you want to play in the blue flame - but it needs to generate some heat or else you also may never make it to boil. For the sweet spot in my experience, you want the flame to just turn yellow on the edges as it meets the pot. Also, as much as you can control it, you don't want flames going up the side of the pot.
Now that you've made things hard, try making them simple. Take a beer can and cut off the bottom inches with a pair of scissors. This is your stove. You are done. There is no more work to do. Cut up a pot stand from a can of beans or something so that the stove sits about 1-2 inches above the stove. Compare the performance of the easy made stove vs. the more difficult ones. The more difficult ones should outperform the simple one, but not by a "trail amount" (i.e, you won't care when you are out hiking).
Another simple approach is what I use - take a tea light candle tin and fill it up to the top with alcohol then light and put your beer can pot on a hardware cloth pot support (1.5 inches high)and toss on the soda can sides windscreen (side wall from two soda cans crimped together on one end and slotted together on the other with paper punched holes along the bottom edge); use a piece of foil for the lid to the pot and hold it in place with a granola bar. Other than the fact I only boil about 1.75 cups of water this approach works well for zip lock cooking,
http://timberwolf.us/SuperCat (http://timberwolf.us/SuperCat)
One of the most east to build stoves. Pot sets on stove.
You can see a picture of mine at.....
http://webpages.charter.net/fam-strick/SuperCat20-10.jpg (http://webpages.charter.net/fam-strick/SuperCat20-10.jpg)
I have built several, and the one I like most uses 20, 3/16s holes
around the top and 10, 1/4" holes for the burner. I just raise the
bottom holes 1/16.
The Hammocker
03-14-2005, 22:00
Now that you've made things hard, try making them simple. Take a beer can and cut off the bottom inches with a pair of scissors. This is your stove. You are done. There is no more work to do. Cut up a pot stand from a can of beans or something so that the stove sits about 1-2 inches above the stove. Compare the performance of the easy made stove vs. the more difficult ones. The more difficult ones should outperform the simple one, but not by a "trail amount" (i.e, you won't care when you are out hiking).
Okay, here is something even simpler:
put holes in the sides near the tops. No potstand needed!
schwenkler
03-15-2005, 01:35
Have to second the Hammocker's suggestion. I made a can stove without really knowing how, from the top & bottom of a coke can, fit over one another to make a "short" coke can, with holes poked around the diagonal-sloping rim of the can. I can pour the alcohol through the top, sit my pot right on it, and it creates a pressure stove so the flames actually look just like a gas range.
My only major difficuly is priming the stove. It sometimes works to light the fuel that pools on the lid of the can, other times I need to spill more fuel around the sides & bottom.
mbroadhe
03-18-2005, 22:59
This is what I did. My inspiration came from the Vargo Triad Stove. I took one 16 oz. can (Guiness) and cut the bottom off 5/8" high. Then, I took a 12 oz. can (Coke, Pepsi, etc.) and cut the bottom off that 5/8" high. I drilled one 1/16" hole in the center of the 16 oz. can and sixteen 1/16" hole around the outer lip of the same can. Then, I put a little JB Weld around the interior of the 12 oz. can and squeezed the 16 oz. can inside the 12 oz. can. A simple shim made from extra aluminum from either can will aid you in getting the 16 oz. can inside the 12 oz. When it's in all the way, the stove should stand 1" tall and you should see the bottom of the 12 oz. can through the 1/16" hole in the center of the 16 oz. can. I then put JB Weld to fill the crack around the top/side of the can where the bottom half ends. The stove will hold 1 oz. of fuel. When it's full, the alcohol will pool up in the center. This is what you'll use to light it. It takes a little time to prime, but when the pressure builds up and the side holes light, it burns very nicely. A windscreen and pot stand are a must. Here's a few pics of the first one I built.
This is what I did. My inspiration came from the Vargo Triad Stove. I took one 16 oz. can (Guiness) and cut the bottom off 5/8" high. Then, I took a 12 oz. can (Coke, Pepsi, etc.) and cut the bottom off that 5/8" high. I drilled one 1/16" hole in the center of the 16 oz. can and sixteen 1/16" hole around the outer lip of the same can. Then, I put a little JB Weld around the interior of the 12 oz. can and squeezed the 16 oz. can inside the 12 oz. can. A simple shim made from extra aluminum from either can will aid you in getting the 16 oz. can inside the 12 oz. When it's in all the way, the stove should stand 1" tall and you should see the bottom of the 12 oz. can through the 1/16" hole in the center of the 16 oz. can. I then put JB Weld to fill the crack around the top/side of the can where the bottom half ends. The stove will hold 1 oz. of fuel. When it's full, the alcohol will pool up in the center. This is what you'll use to light it. It takes a little time to prime, but when the pressure builds up and the side holes light, it burns very nicely. A windscreen and pot stand are a must. Here's a few pics of the first one I built. The problem is that to prime it you must you 1 oz. It may not take 1oz to cook what you need but you have to use 1 oz to even get it to start. If it were not for that one thing it would be a pretty rad little stove. And yours seems safer than the triad.
SGT Rock
03-19-2005, 00:28
The Vargo is a titanium gimick. One of the absolute worst performing alcohol stoves I have ever messed with. BUT LOOK, IT'S TITANIUM :rolleyes:
mbroadhe
03-19-2005, 00:49
Well, you can use a penny to cover the hole if you only want to use a 1/2 oz. of fuel and pour a bit on top of the penny to prime it. You're right about that Vargo. I was looking at it going "30 bucks? I can build that for practically free!" I haven't had a chance to put my stove to the test in the field yet, but I have lit it and boiled water on it outside in 20 degree weather.
SGT Rock
03-19-2005, 00:53
My experience with the stove:
Too heavy for what it is.
Too hard to fill for what it is.
Too expensive for what it is.
Titanium does not conduct heat well, a good alcohol stove uses the metal to heat the alcohol, Ti=bad alcohol stove material. Aluminum is much better. Silver would work best, but that is a whole other subject.
Doesn't seal correctly, yet uses a sealed stove design.
Makes a roayal mess with flames, a hazzard to shelters and tables.
In short, a poor idea for a stove, other than it is cool to people that want something made from titanium. :datz
Now if you wanted a smart use of titanium in a stove, I know this stove called the Ion... ;)
Now if you wanted a smart use of titanium in a stove, I know this stove called the Ion... Nice plug. lol
What most people don't know about titanium is that aluminum is lighter. Yes you read that correctly. Two objects with the same dimensions but one made of aluminum and one made of titanium, the aluminum will be lighter. Also if you make those two objects out of steel and titanium, the steel will be stronger. Then whay is titanium so great you ask, because it is almost as light as aluminum and almost as strong as steel. It combines the two but isn't always better. An aluminum pot is almost always lighter than titanium. When titanium becomes advantagous is like in hiking poles where they have taken the strength of titanium to allow them to make smaller diameter tubes than aluminum. So it isn't that titanium is lighter, it is because titanium is stronger allowing them to use less to make them as strong utimately making them lighter. Titanium is also closer to being an insulator than a heat conductor and makes for lousy cooking pots/pans. I do like it as a cup though, not any lighter just alot stronger, and because it does seem to insulate some it doesn't burn yur lips like a steel or aluminum cup full of hot coffee can.
I've used, and like the Vargo Triad. I agree about it being overpriced, but I do like the fact that you don't need to use a stand with it, as you do with many alcohol stoves. I've made plenty of pepsi-can stoves, some with insulation, some without, but I like the Triad better. It's far sturdier, and, like I said, comes with it's own stand. I have no problem whatsoever cooking with it, I got water to boil even faster than advertised even in cold weather.
SGT Rock
03-20-2005, 11:11
I've used, and like the Vargo Triad. I agree about it being overpriced, but I do like the fact that you don't need to use a stand with it, as you do with many alcohol stoves. I've made plenty of pepsi-can stoves, some with insulation, some without, but I like the Triad better. It's far sturdier, and, like I said, comes with it's own stand. I have no problem whatsoever cooking with it, I got water to boil even faster than advertised even in cold weather.
Almost any stove will boil faster than advertised if the maker is smart. The not so smart ones claim something they cannot always do, while the smart ones claim something achievable in almost any weather and then let you be pleasantly surprised when they work faster. The trick is to figure out who is testing and reporting correctly and who judges based on hope and visual observation.
Anyway, if you like pepsi stoves and don't want to monkey with a separate stand and all, there are better performing, lighter, cheaper, and sturdy designs. For $30 I would expect something more than a titanium photon stove with a built in tripod.
Perhaps, but the stove works just fine. It boils just as fast as the pepsi can stoves I've made and used, and is far sturdier. Who cares if the material the stove is made of doesn't conduct heat well, if it works just fine? I've seen stoves that also include stands such as the brasslite and others, and they just don't seem as sturdy or compact as the Vargo Triad. They also don't seem as easy to empty of alcohol if you don't use all the alcohol in the unit as the Triad. The Triad functions well for what it was designed to do, that's all I need it to do.
SGT Rock
03-20-2005, 11:54
As long as you are happy with it, that is all that counts.
It may perform just as well, and is sturdier, but a pepsi stove cost little to nothing to make, so who cares if it gets crushed. They are so easy to make you can make another on the trail. Besides on a AT thru-hike you probably should have more in your bounce box.
But as Rock says, "as long as you are happy."
mbroadhe
03-20-2005, 15:16
But as Rock says, "as long as you are happy."I do believe that's the key here. Use what you are comfortable with. When making your own stove, make a couple different models, sizes, etc. and use the one that performs best for you. It's a matter of experimentation. I wouldn't tell you what size, make, or model kitchen stove to buy and I'm not going to tell anyone what hiking stove to build or buy. I just wanted to throw out another design idea that I built up and haven't seen anywhere. It surely helps to read others reviews of different stoves to aid in their purchase or build, but in the end, you are going to be the one cooking on it. It's not worth doing if it isn't any fun.
But as Rock says, "as long as you are happy."
I think that's the main point. I've made a bunch of pepsi can stoves, and the cat food can stoves, I even made one from Red Bull cans. They all worked, some better than others, and I preferred some to others. I got the Triad because I thought it was an interesting design, and wanted to see how it worked out. It has worked out pretty well, to the point that it has replaced my other stoves.
And yes, I can make a pepsi can stove for little to nothing, but it takes me time and effort to do such things. I can carry the Triad and not really have to worry about my stove getting dented, dinged, punctured, crushed, and whatnot, as some of my pepsi can stoves have. That means I don't have to spend the time and effort to make another Pepsi can stove, and that's worth it to me. I'd rather be hiking than making stoves any day.
grrickar
03-21-2005, 14:13
Titanium does not conduct heat well, a good alcohol stove uses the metal to heat the alcohol, Ti=bad alcohol stove material. Aluminum is much better. Silver would work best, but that is a whole other subject.
Now if you wanted a smart use of titanium in a stove, I know this stove called the Ion... ;)
If it's not good for alcohol stoves, then why do you use it? :p
Are there any good articles dealing with the boil times for aluminum versus titanium?
The benefits I can see for Ti are:
stronger than aluminum, doesn't corrode, higher melting point (yes, in my Scouting days I saw a grease fire melt an aluminum skillet)
As for aluminum:
Cheaper and heats faster (would that not also mean it gives up heat faster, thus cooling the contents more readily?)
My thinking is that aluminum would conduct heat better, but also loses it faster than Ti. That being the case, if water is brought to equal temps in both a Ti and an Aluminum pot, I wonder which one would cool faster?
SGT Rock
03-21-2005, 14:16
Well that subject is more for pots, the advantages and disadvantages are slightly different there. What I was reffering to was more the dynamics of the stove performance.
ThaiChef
03-25-2005, 13:38
Please forgive a new guy for chiming in, but I'm pretty excited about my stove experiences.
I've built a number of stoves over the last couple of months (Pepsi Can, V8, Super Cat and the Ion stove most recently).
I've enjoyed what I've learned from each of these stoves, but I am sold on the Ion stove. Given a choice between a top burner and side burner, I think I'll always choose the top burner. The flames from a side burner stove are often off the side of my pans. The other problem that I see is that fuel spills more easily happen with side burner stoves.
I built an Ion stove this week. I used the wedding party favor aluminum tins that SGT Rock uses. It comes with a see through lid that ended up being useful to me.
(*OT dehydrating sidenote*)
Last night I cooked some homemade spaghetti meat sauce on my Ion stove that I had dehydrated last summer. I'm not sure that I could tell the difference between last night's spaghetti sauce and when I first cooked it last summer. I'm sold on dehydrating. I cooked up several Thai dishes this week and have dehydrated those. I'm looking forward to tasting some of these dishes in the mountains....who says you can't eat gourmet food on the trail?:)
(*End OT*)
In my tests last night I used hardware cloth for my stand since I haven't yet purchased SGT Rock's cool TiPod stand.
The stand I used was about 1/4" too high. Because of this the flames were only coming out of the 1" hole. This had the effect of a simmer mode. I removed the plastic from the see through lid and used the metal lid underneath the stove to boost it 1/4" closer to the bottom of the pot. It then went into full cook mode and performed beautifully.
My stove burned for 35 minutes and only used 10 grams (1 Tbl) of fuel (denatured alcohol). I was very impressed.
Thanks to everyone for all the insights they share here. It has been very helpful to me and certainly gets me excited about getting up to the mountains.
ThaiChef