[pct-l] question re-fuel for Caldera Cone System Stove

[Jim Marco]

The caldera cone is very simple and uses the natural physics of a stove to heat water (or to cook.) All alcohol stoves are within 10% efficient of each other. Light alcohols burn readily with no soot. They do not have the heat content of Esbit, though. Esbit/trioxane cubes are about 13000BTU/lb. This is slightly greater than the 11300 (average) for alcohols. Methanol (yellow HEET) only has around 9800BTU/lb. Ethanol is around 12800BTU/lb.
(Wikopedia: http://en.wikipedia.org/wiki/Heat_of_combustion )

There are problems with all fuels, of course, Esbit does not burn cleanly and produces some bad odors (incomplete combustion.) Soo, I am guessing it is closer to 12000 than 13000. It burns slowly (good for recovering heat) but can be painful to light in any wind. 

Ethanol cannot be made or will not stay pure. It always has about 5% water no matter how many times you distill it. So, this means that the actual heat is closer to 12000. It burns a bit slower than methanol, but the specific gravity is only around .8 or so. (About the same as WG.) 10floz of ethanol only weighs 8oz. It will light easily, but the flame can be hard to see sometimes.

Methanol is also not 100% pure. It too has a specific gravity of around .8. It burns faster, so the flame from the stove is hotter, boiling water a little quicker. But, you burn fuel faster. Methanol is used as a denaturing agent in about 10% concentrations or above. Kleen Strip SLX is about 50/50 Methanol/Ethanol. Some other aliphatics are present.

The cone traps heat and channels it along the sides of your pot, hence, adding the sides as heating area to your pot. An additional 15-20% can be added to the system by introducing four or five 1/8" ridges around the bottom of your pot. Typically ti cannot be reworked. Aluminum can be annealed then pounded in a small jig, then burnished with a small tool. Painting the bottom of the pot will also help with heat (IR) absorption another 5-10%. Coupled with the cone, you can reduce the fuel you need by about 40-50% by preparing stuff. A standard cone is about as efficient as it gets, but aluminum ones will not take the heat of a wood fire. Get the ti if this is what you plan on. A SLOW burn in a cone is more efficient than a fast burn, I recommend making a simmer ring for the 12-10 stove and using it. This is where the GramCracker Esbit stove really shines (ha, ha, even if it makes a mess.) Typically, they fit into the hydration sleeve of your pack and add a little to stiffening the pack, also, if you have a full length sleeve.  

There are rules and regulations about uncontrolled flames in some areas of the western states. In places you cannot use alcohol stoves. It has the heaviest starting weight, but the lightest finishing weight when coupled with a cone over a week. I prefer it for trips between 1-4 nights out. Alcohol/cone stoves can be difficult to cook on. They never fry too well, and may not perform well making stews/soups, macaroni/marinara sauce, fried veggies & rice, etc. A 15 minute simmer can be painful, since you may have to refill once or twice...heat regulation is not possible except within a narrow range on the 12-10...

Anyway, call Rand at Trail Designs for more info. He does NOT list everything he offers on the web site. A simple cone with no cutouts that fits a three cup pot is ideal for solo trips. You have to sacrifice something to go lighter. He can also be emailed with any questions...tho' he may take a few days to respond.

My thoughts only . . .
	jdm