Mar 6, 2011 at 9:45 am #1270115
Thinking that a caldera cone is sort of an inverted chimney kettle, I was reminded of this at "http://www.bushcraftuk.com/forum/showthread.php?t=54683&page=1" forum, where
"I've been experimenting with an old stainless thermos to create a "reverse kelly" where the flames run up the outside of the inner bottle inside the outer jacket. I've just got to make up a hobbo stove the right size for it to sit on."…
This made me thing a MYOG inside out chimney kettle based on beer can would be easier to build:
Keeps the simplicity of a chimney kettle, other than may have to remove "pot" to add more fuel.
A steel can forms lower part of windshield/fire box, stiff foil/tube the upper, from which the beer can pot hangs: perhaps on horiz struts.
Diagrams are better than words so:Mar 6, 2011 at 9:46 am #1705084
an additional foil windscreen could be used to increase efficiencyMar 6, 2011 at 3:02 pm #1705178
I see several problems with that .
First the can (IMHO…) would be too fragile for the handling required.
Second how exactly do you pick the pot up to either add wood or to pour water out when ready ?
(In fact as per the drawing the only way to have water in the pot would be to set the pot up inside the "cone" then add water to it. That is another problem In itself because the pot would melt if the fire is going (as well as burning your fingers doing it), if on the other hand the fire has not already started how do you light it once the pot is in place ?)
Thirdly to have enough clearance under the pot and around it the screen would have to be about 10" x 16-18" so not that light..
Maybe just a Nimblewill type burner and a pot on top is an easier way of doing it…Mar 6, 2011 at 4:05 pm #1705201
@cadyakLocale: southwest georgia
just make one and see how it works….Mar 7, 2011 at 11:33 am #1705564
I should have drawn U shaped cutouts for the + of pegs which support the pot:
thus pot can be lifted out.
The pot could be reinforced around the pegs.
Surely the beer can shouldnt melt if contains water, the lower outer can is steel, the upper cylinder: whatever works.
I would have thought it could be light enough .
Light fire though lower vent,just like a real ghillie kettle.Mar 7, 2011 at 12:21 pm #1705592
@b-g-2-2Locale: Silicon Valley
"Surely the beer can shouldnt melt if contains water"
Simply containing water may not be sufficient. It probably needs to be filled with water so that all aluminum has water behind it. Your sketch shows that the beer can is not filled.
–B.G.–Mar 7, 2011 at 2:31 pm #1705673
You could always insert a couple of pegs under the pot rather than at the top, but in the end is not much different than something like the TiTri Caldera cone in wood burning mode.
And yes, if you do not have water all the way to the rim, there is a pretty good chance that the aluminium will soften and then melt where not in direct contact with water.
(that is because with wood you do not really have any control over the height of the flame)
This still leaves you with another two problems. If you fill it to the top it will overflow when it starts to boil.
Next it will be very difficult to lift it out of the fire without spilling/bending the can .
FrancoMar 8, 2011 at 1:11 pm #1706185
Devin Montgomery's back country boiler is all aluminium and and the chimney extends beyond the water:
a chimney kettle is tall by definition, shouldn't this reduce the heat at the top of the can, plus if its filled pretty full with wtaer, the heat can be conducted to the water.
If an aluminium can is no good, I you could use a steel can (or carry a spare beer can)Mar 19, 2011 at 1:25 pm #1711244
I built a rough version out of a coffee tin (lower one ) and a smash (instant potato) tin (with bottom cut out).
They clicked together without any further adaptation.
I used a baked beans tin as pot for testing (foil lid show). 2 parallel pegs hold it in place / act as handle. It would be better if lower fire box tin was half its height (and upper 33% taller), but OK . Twigs could be dropped down the (chimney) gap.
Seemed to keep Volcano Chimney kettle advantages of
1) soot always inside
2) chimney effect making fire burn.
I think a cocktail tin might be an alternative for the "pot".
I think it could be made lighter using cones (NB above test unit and this cone idea differs from a caldera cone ti-tri in that I want the a taller cone(for chimney effect) and the cone encloses whole (conic?) pot (for efficiency/keeping soot inside everything).
Here is a blurry photo:Mar 24, 2011 at 2:18 pm #1714148
I weighed the pictured stove (excluding pegs, but including tin can "pot") and it was a reasonable 8 or 9oz. That seems quite reasonable.
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