Multi-fuel stove support for Open Country 3-cup HA pot

[Bob Moulder]

My goal was to come up with a pot support that would work equally well with some combination of alcohol burner and Esbit tray, without having to modify the burner-to-pot distance for either fuel type. Of course, it was also important to maintain fuel efficiency.

I realize there is a Caldera Cone made for this pot, but I wanted the whole kit — pot support, windscreen, plastic coffee cup, pot lifter, spoon, Bic lighter and fuel — to fit inside the pot. With Esbit, the fuel fits inside the pot easily, but it doesn't for alcohol. I think I could fit enough Esbit tabs to last a few days, however.

After experimenting with a few different alky (12-10, Evernew, Starlyte) and Esbit (Gram cracker, FF14, BGET) burners and pot support heights, this is what I came up with. It will easily boil 3+ cups of water using either one 14g Esbit tab or 25ml of alcohol. The fuel burners are a BGET without the end tabs that raise it, and the basic Starlyte alky burner.

The pot support is made from .005" Ti from Titanium Goat, requiring only scissors and a hole puncher. It weighs 7.7 grams and will easily support a Toaks 1350ml filled to the rim.

Although I have not used the CC/OC pot combo and can't compare them for efficiency, I am convinced that the slightly increased dwell time of the flame caused by the pot support does indeed improve efficiency and probably rivals CC, although it is probably not as good as CC when it is very windy.

EDIT: pot support dimension is 2.125" height and 11.75" length.

[Bob Moulder]

How could I forget??

Weight for everything (minus fuel) is 7.4oz (Esbit) and 7.70z (Starlyte)

[JCH]

Nice! Love the dovetail closure on the pot support.

[Dan Yeruski]

Looks great!

When it's burning does it smell like it's getting complete combustion?

Is the residue on the pot just soot or does it have a gooey substance?

How much dwell time do you think has been added by the windscreen?

We know the BGET slows down burn rate and increases efficiency.

Yes, the dovetail looks like it works well….does it? Is it easy to insert the dovetail into slot?

[Bob Moulder]

Dan, smells to me like complete combustion, and the soot on the bottom contains zero gooey stuff, which is the first time I've ever seen that happen.

Also, with Esbit a full boil is achieved around 14 minutes or so and continues to boil until about 17.5 minutes, which indicates to me not a whole bunch of wasted fuel.

The soot on the bottom was from 3 burns and it wiped right off with only a few little pinhead-sized black dots remaining. I don't know how to quantify the dwell time, but I'm thinking that it contributes to a complete burn. Of course the overall efficiency is the result of all factors, with air intake and gas exhaust, etc, and the high sides of the aluminum windscreen also help there. The dimensions of that OC pot really hit a sweet spot for this volume of water.

The dovetail thing does indeed work well. The slot is a little bit smaller than the end of the dovetail, and it slides in easily when the dovetail is canted over slightly, but it won't pull out straight, especially when there's a pot sitting on it. Pretty cool that something that weighs 7.7g can support ~1500g fairly easily.

[Jameson Tisch]

Reminds me of this thread from Newton.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=69149

[Bob Moulder]

Jameson, I followed the link at the end to read Newton's full thread and it seemed at the end he was not happy with the results… something like 14 minutes for a full boil of 1 cup.

With my setup I'm boiling (rolling boil) 3 cups of cold (~50°F) water in about 12 min with Esbit and about 8 min with alky.

The much increased efficiency comes from the wide pot, the windscreen that channels hot gases around the pot, and the proper intake/exhaust of air/gases that controls burn rate. And based upon my observations of other burners and pot supports in operation, I speculate that the pot support I'm now using also contributes to the efficiency. I don't think these efficiencies can be achieved (at least not easily) with tall, skinny vessels.

I did a couple more test boils using the Gram cracker and FF14 and was able to achieve boils in about the same time, but they did not burn nearly as cleanly as the "legless" BGET.

The photo below is of the pot bottom after a burn with the Gram Cracker.

[Dan Yeruski]

Quote from esbit testing thread:

A Caldera Cone for KEG with 32oz beer can will boil 4 cups with 1-1/2 fourteen gram tablets. It a nice kit for 2 people. Use the large silicone band to lower a non ribbed can down to the 1-1/2" above the esbit. I know it works with a BGET tray.

[Bob Moulder]

No doubt this is true!

I noticed that using 1.5 tabs gave me a full rolling boil and then some, so this morning I did some boils using 1.25 tabs to compare my pot stand/windscreen with the Ti-Tri cone, both using the Toaks 1350ml pot and the BGET.

Starting with 4 cups of 50°F water, using the cone it got up to 206°F with the Ti-Tri cone, but I actually achieved a full rolling boil using my pot stand and a windscreen. Tested a couple of times each, so I can say without question that the pot stand/windscreen is more efficient, at least with this combo. In essence, a full boil with 17.5g of fuel.

[Dan Yeruski]

I also experienced no boils in the Cone and was able to get the boil with a straight wall windscreen in some tests last month when doing esbit. It's as if the cone restricts air flow under certain circumstances. Makes ya scratch yer head in wonderment!

[Bob Moulder]

Makes ya scratch yer head in wonderment!

Ah, glad to see this replicated elsewhere — I thought I must've been doing something wrong, which is why I did it twice and monitored the full burns with the thermometer…

Interesting what you discover while "putzin' around with stoves"! ;^)

[Bob Moulder]

This pot support seemed pretty strong, which of course invited the question "How strong?"

My intention was to put a full 2-quart pot on top, but I forgot that I had donated that one to my friend's BSA Troop. But the old 4-quart pot was still in the attic, which would suffice.

It supported the full 4-quart pot easily… a weight of at least 8.5lb (3.86kg)… and the dovetail connector tab didn't even flinch, even with the large pot rather significantly off center. Obviously it is more than strong enough for the typical UL cook setup.

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