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Help me figure this out

Posted: Sat May 05, 2018 9:07 am
by markhait
I've been a backpacker for a long time but have been out of it for a number if years. Well, I'm back and after my last trip, 3 weeks ago, in a blizzard in northern Michigan, I've decided to start using alcohol stoves again and I've come across something that's driving me nuts!

I bought a Caldera cone with a 12 10 stove and a Kojin stove. I'm using a Evernew Ultralight 1L pasta pot and I cannot get consistent boil times. I was in my garage testing yesterday and my times were wildly swinging to extremes. I broke out my Starlite stove and got the best boil time, but when i tried it again, I didn't even reach boil!

I am confused!!! I'm using denatured alcohol, 2 cups of tap water and 15 ml of alcohol. At first, all the stoves boiled, now none of them do. I can't understand what's going on. Is my setup with the Caldera cone too high for the Starlite and the Kojin stoves? I couldn't find any info for optimal stove to pot height.

Thank you in advance for your help

Re: Help me figure this out

Posted: Sun May 06, 2018 11:38 am
by zelph
Hi Mark, good to see you again.

I venture to say your pot is too large for 15ml of fuel. Your pot is for 4 cups, therefore more metal to heat up.

The surface of your test spot is heating up and therefore in subsequent tests, the burners are heating up faster causing fuel to be consumed faster, therefore less efficient (no boil)

The Kojin burns faster than the Starlyte because of the absorbing material used inside is different. Vaporization of fuel is faster in Kojin.

Your tap water may not be the same temperature each and every time you do a test. Your pot maybe a different temperature when you pour water into it.

Boil tests are a science. High humidity has an adverse effect on boil times. A storm from can move in and cause a no boil situation within an hours time.

It takes me many many hours of testing to design a stove. I always use the same pot, one that holds 2.5 cups of water. I do my tests inside the house when my wife is not home. Room temperature is controlled by air conditioner or furnace. Water comes from faucet that is single lever for temperature control. Water flows into pyrex measuring container that has thermometer in it so I can do a visual to know when starting temperature of water is same for all tests.

A stove under ideal conditions has to produce 3 consecutive boils with same results in order for me to know it's capabilities. Once the stove leaves the house, I have to make allowances for boil times/fuel usage on the trail or in the garage My garage is much cooler in the morning than in the afternoon. Variable, ohhhh those variables. A stove designers nightmare. :-))))

Re: Help me figure this out

Posted: Sun May 06, 2018 6:08 pm
by markhait
Thanks for all the suggestions Zelph!
I experimented more today using 1 ounce of alcohol and had no problem at all with any of the stoves getting
to boil. My work table is a 5" thick tool makers granite table and I moved the stoves around on it in case I was warming
it up in the same spot. I have a Snow Peak titanium mug with a lid that I bought a long time ago. It holds
maybe 3 cups of water and I used that and had no problems boiling using 1 ounce of alcohol.
I'd like to use the Fancy Feast stove I bought from you a few weeks ago as my main backpacking stove,
but maybe I don't have the right sized pot for it.
I eat all mountain house freeze dried food on the trail and I never have to boil more than 2 cups of water.
What would you suggest to be the smallest, lightest pot for your stove? Something short and fat?
Are you a titanium fan or do you prefer aluminum for heat conduction?

Re: Help me figure this out

Posted: Sun May 13, 2018 8:26 pm
by zelph
Short and fat is best in aluminum with 2.5 cup capacity.

Toaks 700ml is a nice titanium pot that I have zeroed in on and my old reliable boy scout aluminum pot with a bail handle. It has a 2.5 cup capacity with a 5.5" diameter.

This is blueberry pie filling with a Bisquick dumpling using the Toaks Light 700: