candles / lighters to boil water in a beer can?

[ingear]

i hope this is the best place to ask this ..

since many of us here like technical & engineering & etc ..

what would be a general formula to compute boiling time for water in a 12 oz beer can using X# of candles OR X# of lighters .. (at sea level and all etc nominal..)

and how does the formula / time change if the can is sealed (say full of beer)

i assume it is

7 minutes for water if using 5 candles (would lighters be the same)
and 4 minutes for sealed can?

lets see..

why? we go hiking/trekking/camping often and are wondering .. and hot tea/soup in evening / morn8ng from this method might be so warming and will test this out ..

 

[LTC8K6]

You want to heat/boil a sealed can of water? GLWT.

IIRC, if you are camping/trekking, you will be using a stove meant for the purpose, and they will generally give you water boil times.

 

[sdifox]

You understand beer cans are lined with BPA right? So boiling water or beer can chicken are both very bad ideas.

 

[edro]

homework

 

[deadlyapp]

Some random googling gives me the following:
Takes around 171kJ to heat a half liter of water from room temp to boiling


One tea candle outputs around 547 kJ over around 4-5 hours, so lets say around 100 kJ/h = 27.7 J/s (watt) or .0277 kJ/s. Assuming maybe 50% efficiency (losses from the water to the environment, candle inefficiencies, etc), you'd need like 30 candles to heat a can in 7 minutes.

I'm not sure how much heat output butane from a lighter has, but it's probably similar to Paraffin wax.

 

[MongGrel]

homework

Sounds like it, why would anyone used candles to boil water in a beer can.

Or do that to begin with.

 

[dave_the_nerd]

Yeah, this idea sucks. Look up "chemical heaters" - you can get a mug that heats up whatever you put inside it. Not unlike how MREs work.

 

[tynopik]

why? we go hiking/trekking/camping often and are wondering .. and hot tea/soup in evening / morn8ng from this method might be so warming and will test this out ..

Normally the idea is to NOT lug around the fuel while hiking

you carry the ignition source and find fuel where you stop

unless you're hiking in antarctica or something

 

[deadlyapp]

Normally the idea is to NOT lug around the fuel while hiking

you carry the ignition source and find fuel where you stop

unless you're hiking in antarctica or something

That is asinine. Any serious backpacker takes fuel with them.

 

[NikolaeVarius]

Normally the idea is to NOT lug around the fuel while hiking

you carry the ignition source and find fuel where you stop

unless you're hiking in antarctica or something

I guess we should also be foraging and hunting for all food requirements rather than bringing dried food along right?

 

[lxskllr]

Yeah, this idea sucks. Look up "chemical heaters" - you can get a mug that heats up whatever you put inside it. Not unlike how MREs work.

I looked up MRE heaters after seeing this thread, and they're kind of spendy to buy for food heat; >$1 per heater. On the bright side, I bought a case of MREs. Can't wait. I haven't had them in a long time :^)

 

[herm0016]

http://www.thesodacanstove.com/alcohol-stove/how-to-build.html

 

[Gooberlx2]

LOL, candles would take fucking ages.

Look into Esbit, or DIY fancy feast alcohol stoves if you're trying to go ultralight. If you're somewhere with fire restrictions, you'll probably need to stick to isobutane and a stove with a valve.

 

[Gooberlx2]

Normally the idea is to NOT lug around the fuel while hiking

you carry the ignition source and find fuel where you stop

unless you're hiking somewhere with little natural fuel or anywhere with fire restrictions, like the entire Rocky Mountain West or something

FTFY

 

[Imp]

You understand beer cans are lined with BPA right? So boiling water or beer can chicken are both very bad ideas.

Serious. Aren't aluminum cans lined with plastic to protect the contents and metal?

 

[lxskllr]

Serious. Aren't aluminum cans lined with plastic to protect the contents and metal?

bpa is a component of plastic, and it may or may not find its way into beer can coatings. I'm not satisfied that "bpa free" has any real meaning. I think people will find over time, the replacements aren't much better.

 

[Linux23]

This thread rocks!!!!

 

[Artdeco]

Ignoring the BPA thing, the FDA does not test plastics when heated, many plastics are known to produce carcinogens when heated or burned.

 

[Red Squirrel]

A standard tea candle emits about 200-250 BTU of heat, the problem is directing that heat to the can and only the can. If you just have a standard holder like you'd use with say a bunson burner, most of that heat will just go around the can. If you put your hand over the can and feel heat, it's wasted heat. What you can do is build a sealed system that the can sits into and the flame is inside the sealed system, idealy it would be fire safe and an insulator. To avoid flame out, you should add an oxidizer. Rust will probably work but you need a way to feed it to the fire. In fact, ditch the candle, and go with hydrogen, it will make a cleaner and more controllable burn, and use liquid oxygen for the oxidizer. Using a series of servo controllable valves as well as a h2, o2 sensor and flame sensor you will be able to use a microcontroller to fine tune the combustion process automaticly.

If all goes well, you'll end up with boiling water in no time. If all else fails, you might send a beer to the ISS. These last call alcohol delivery services are really getting out of this world.

 

[Charmonium]

fire cubes

 

[DrPizza]

The more slowly you heat it, the more heat is lost from the water due to cooling. The rate of cooling is proportional to the difference in temperature between the water and the surrounding environment. It's quite possible that a candle would never be able to heat it faster than it cools - it'll reach equilibrium at a temperature below boiling.

Since you have cans and candles, what would work more effectively would be to have the wax supplement a fuel source. E.g., take the bottom 1" of a can, or use something like a tuna can, tear newspaper into strips roughly the height of the can. roll them up fairly tight, but not too tight, and keep rolling until the diameter of the rolled up cylinder of newspaper strips barely fits into the can. Insert into the can. Hold a burning candle upside down so that most of the wax melts and drips into the paper in the can. Then, use the can as a fuel source - far more btus, and much quicker boiling time.

 

[lxskllr]

I looked up MRE heaters after seeing this thread, and they're kind of spendy to buy for food heat; >$1 per heater. On the bright side, I bought a case of MREs. Can't wait. I haven't had them in a long time :^)

Got my MREs today! Super fast shipping, and they were packed in 2014, not 2012 as advertised, so that's another bonus. I'm gonna try to wait until fall before I get into them, but it'll be hard to wait. Having hot food in the field without elaborate cooking apparatus is a minor miracle.

 

[sdifox]

http://solarcooking.org/plans/collapsible-box.htm

 

[HeXen]

Got my MREs today! Super fast shipping, and they were packed in 2014, not 2012 as advertised, so that's another bonus. I'm gonna try to wait until fall before I get into them, but it'll be hard to wait. Having hot food in the field without elaborate cooking apparatus is a minor miracle.

Since I work outside and usually take my food with me, I actually thought about getting some MRE's to take in the winter time instead. It's really difficult for me to bring hot food and keep it hot until noon but the price for MRE's has been the downer.

How much do you find them for? If I can get each pack for about the cost of what I prepare or a tad more, I'd order me some.

 

[lxskllr]

How much do you find them for? If I can get each pack for about the cost of what I prepare or a tad more, I'd order me some.

I got these for what I consider a pretty good price; ~$80 for a case of 12 meals. You can pay a lot more, but you won't find them for much less. So, you're looking at the the cost of McDonalds lunch per meal. Each meal is about 1300 calories.

Objectively, it's not the absolute best use of your money. You could find another way of getting hot food, but it would take more time/gear to achieve. MREs are just cool as hell. You get everything aside from water in a rugged sealed bag. I got hooked on them when I worked with a Guardsman. I used to love watching all the crap he pulled out of the bag.

edit:
the meals come in cases, and are either menu A or B. 1-12 is A, and 13-24 is B. You can see what's included for year packed, at this site...

http://www.mreinfo.com/mres/mre-menus/

That site has other good info if you poke around.

If you go the MRE route, make sure you buy genuine military issue with the flameless heaters. There's other MRE-like packs not made to government specs, or government produced for non-military use, but they aren't as thorough or useful.