1/2oz//2cup boil?

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russb
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Re: 1/2oz//2cup boil?

Post by russb » Thu Feb 28, 2008 10:16 am

I've got a few sierra cups laying around. I think I will play with them a bit. I am thinking the Starlyte might be a good stove to use with the small sierra cup.

oops56
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Re: 1/2oz//2cup boil?

Post by oops56 » Thu Feb 28, 2008 11:43 am

I got a wok make that nickel stove penny melts

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Man play with fire man get burnt

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Ridgerunner
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Re: 1/2oz//2cup boil?

Post by Ridgerunner » Thu Feb 28, 2008 6:26 pm

You the old copper penny, the new onw is junk and will disfigure.
"Many of lifes failures are people who did not realize how close they were to success when they gave up".....Thomas Edison

"Live Life....Love Life....Ask More !

Allen
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Re: 1/2oz//2cup boil?

Post by Allen » Thu Feb 28, 2008 9:22 pm

I just ordered a 16 oz. Sierra Cup to use as a wok.
It's too small to wear as a helmet like oops56, so
I'll have to carry it in a backpack the regular way :)

Cheers!
Allen

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DarenN
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Re: 1/2oz//2cup boil?

Post by DarenN » Sat Mar 29, 2008 9:44 am

some mathematics:

my digital kitchen scale tells me that 1/2oz of methyl hydrate weighs 1/2oz. there's 32 half-ounces in a pound, so if we use 10,000 BTU, that comes to 312.5 BTU per 1/2oz.
2 cups of water weighs 1pound 1.3 ounces (1.081pounds).
from 70 to 212 degrees= 142 degrees.
so, if the math is right, it should take 153 BTU to bring 2 cups to a boil. less than half the potential of 1/2oz of fuel.
( i still haven't reached the 1/2oz//2cup boil)
edit: if denatured alcohol has a potential of 13,000 BTU (read that somewhere), then 1/2oz has a potential of 406.25 BTU.

something else that's bothering me:

my test data is regularly showing an overlap in boil/burn times. example: one of my latest burners will boil on 3/4oz in 7minutes. it will not boil on 1/2oz but burns for 9minutes. can anyone explain this to me?

DarenN......
Last edited by DarenN on Sat Mar 29, 2008 11:47 am, edited 1 time in total.
"I'd rather be happy than right." Slartibartfast

oops56
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Re: 1/2oz//2cup boil?

Post by oops56 » Sat Mar 29, 2008 10:08 am

Well put it this way try a windscreen.Now if i got alcohol stove that does not boil on a1/2 oz. or get to 180F i junk it. p. s. 16 oz. of water
Man play with fire man get burnt

Allen
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Re: 1/2oz//2cup boil?

Post by Allen » Sat Mar 29, 2008 11:30 am

DarenN wrote:some mathematics:

my digital kitchen scale tells me that 1/2oz of methyl hydrate weighs 1/2oz. there's 32 half-ounces in a pound, so if we use 10,000 BTU, that comes to 312.5 BTU per 1/2oz.
2 cups of water weighs 1pound 1.3 ounces (1.081pounds).
from 70 to 212 degrees= 142 degrees.
so, if the math is right, it should take 153 BTU to bring 2 cups to a boil. less than half the potential of 1/2oz of fuel.
( i still haven't reached the 1/2oz//2cup boil)

something else that's bothering me:

my test data is regularly showing an overlap in boil/burn times. example: one of my latest burners will boil on 3/4oz in 7minutes. it will not boil on 1/2oz but burns for 9minutes. can anyone explain this to me?

DarenN......
I have noticed that the amount of alcohol effects primimg time. I'll pay more attention to the effects
on Boil time. Thanks for the stats! :)

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DarenN
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Re: 1/2oz//2cup boil?

Post by DarenN » Sat Mar 29, 2008 12:44 pm

oops56 wrote:Well put it this way try a windscreen.Now if i got alcohol stove that does not boil on a1/2 oz. or get to 180F i junk it. p. s. 16 oz. of water
i've tried a bunch of different windscreens. some burners don't like windscreens at all. too much turbulence under the pot.

iv'e got a hundred burners that are junk cause they won't boil 16oz of water on 1/2oz of fuel. :lol:

i still think it's the fuel itself that's holding me back.
Oops (or somebody! PLEASE!! :cry: ) get some Methyl Hydrate and compare it to Denatured Alcohol in a burner that you KNOW will boil 2cups on 1/2oz. then, if it works, send me the burner so i can die happy. :D
"I'd rather be happy than right." Slartibartfast

Allen
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Re: 1/2oz//2cup boil?

Post by Allen » Sat Mar 29, 2008 2:49 pm

Methanol has always out preformed denatured alcohol in My tests DarenN.

S-L-X- Denatured does make a pretty redish purple flame in My Fosters Can Stove, so I keep a Qt. on hand for that. :)

I'm sure You know that Denatured Alcohol is actually a blend of Methanol and Ethinol. One Brand (Southern ?) has been accused, on some blogs of using mostly ISO alcohol. You never know what You are burning, from Brand to Brand,
or even batch to batch.

Tony
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Re: 1/2oz//2cup boil?

Post by Tony » Sat Mar 29, 2008 5:12 pm

Hi all,

This is my 2CW on alcohol fuels.

I am currently doing some work on alcohol fuels for an article. I work in a science lab and specialize in accurate temperature measurement and I have set up a testing facility in my garage at home I have run hundreds of tests with different alcohols.

The results are the performance of an alcohol fuel is ‘usually’ related to the heating energy available in that fuel. See chart below. I have stated ‘usually’ as I have found that some stove designs that I have tested do not perform very well on IPA but all of the stoves performed much better on Ethyl alcohol than Methyl alcohol.

I am working on IPA mixtures at the moment but IPA on its own produces a lot of soot and in testing it has given me headaches, I do not consider IPA on its own to be a suitable fuel for stoves.

Caution Methyl alcohol is VERY TOXIC both to ingest and absorb through the skin, the fumes from combustion are also very dangerous and a stove using methyl alcohol should have adequate ventilation. Advice is to read MSDS’s on all alcohols.


Name Heat energy in fuel Heat energy in fuel
Mj/kg Btu’s/pound
Methyl alcohol 19.9 8419
Denatured Alcohol
(95% ethyl alcohol) 26.6 11412
Ethyl alcohol 26.9 11570
IPA 30.15 12960


Denatured alcohols are another story, they vary greatly in composition, in Australia they are mostly 95% ethyl alcohol with the rest made up of undisclosed mixtures of Methyl alcohol/water and some very small quantities of other denaturing chemicals but denatured alcohol in the US is another story, a check of data sheets show that the makeup of denatured can have enormous variation, it can be from 42% ethyl alcohol up to 95% ethyl alcohol with methyl alcohol being the main additive up to 50+% but there are many mixtures and it is too complicated to explain here (it would be a large article in itself) some of the additives do not aid combustion and therefore do not help with the efficiency of the fuel, they are there to denature.

In the US the advice I would give is to research the makeup of what denatured alcohol are available and use the one with the highest ethyl alcohol content.

On boiling 2 US cups with 0.5 us fl oz of methyl alcohol I have not achieved this results yet but I have not tested my most efficient stove/pot setup with methyl alcohol, I have had close results of 16.4 mls (0.55 US fl oz) to boil 500 mls (2.11 US cups). Using pure Ethyl alcohol I have boiled 0.5l with less than 11.4 mls (0.39 US fl oz).

Tony

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