I have pretty much got away from candles after my sister found these small TIKI candles at WalMart. The small one on the left burns a full ten hours and the bigger one on the right is supposed to burn 30 hours. I have not burned the bigger one to test it for burn time, but I have burned the smaller one. I believe it would last dang close to 30 hours if not more just going by the results from the smaller one. They are also very cheap, the small one is $0.98 each and the big on is $1.47 each.
I have tested them for leaking. I turned them upside down and left them that way for over a month and they never had even a HINT of leaking. Same results when I turned them on their side and left them. The caps are VERY well made, and seal very very well. You will need something to pry them off with. I myself can not get my fingers under the plastic lid to pop it off. I have to use the back of my knife and even then, it is hard to do because they are on so tight. Basically these will not come off while carrying them in a ruck. The plastic bottle is very tough. I threw it up in the air about 30 feet or so to see what it would do when hitting the concrete. I did this several times and the lid stayed on and the bottle didn't break.
You can pull the wick out to get more heat, but you will not be able to push the wick back in. You will also not be able to put the cap back on unless you cut the pulled out wick back down to its normal length. If you are doing this, I think you will be burning up most of the fuel anyway to stay warm, so who cares. There is a lot of wick inside the bottle anyway, so if you pulled it out a half inch for more heat, you will still have wick touching the bottom of the bottle. If you look close in the bottom picture you will see the wick curling towards the left because it is so long. The bigger candle I was looking at for a 72 hour kit thinking three 10 hour nights of some kind of heat.
Over all I think they are a nice little cheap, compact, durable heat source that won't melt in high temps, or leak all over your gear.
I did use that little mod striker to lite this candle for this picture. I think it is Doc's mod, but I can't remember who posted the idea. Anyway, it took about 10-12 spins and the candle was burning. Put this inside a coffee can and it will give you some good heat. Wrap yourself in a space blanket or poncho liner and set this between your legs and it will keep you warm. I did this before but with a wax candle and coffee can while deer hunting. It will keep you very warm.
