[pct-l] Denatured alcohol, ethanol vs. methanol

Greg Kesselring gkesselr at whidbey.com
Mon Feb 18 17:24:21 CST 2008

yes, you will get soot and a yellow flame.  Isopropyl alcohol is going 
to burn dirty, yellow flame, lots of soot.  That's a given.

But if you mix it 50/50 with denatured ethanol, you may get a clean 
burn.  Tinny at MBD was getting a clean burn with this mixture.  If so, 
then you'd have a fuel that would have slightly more heat output than 
denatured ethanol (mainly because denatured ethanol is up to 50 percent 
methanol which has considerably fewer btu's per pound than ethanol or 
isopropyl alcohol).


Tortoise wrote:
> Boy did I start a thread with my question about isopropyl alcohol.  I 
> bought Safeway brand 99% isopropyl according to the label, in Safeway. 
> don't recall what I paid. I don't know what it else it contains, 
> probably water.  In my cat can stove it burns with a yellow flame and 
> produces lots of soot and the soot collects on my pan.
> Tortoise
> <> He who finishes last, wins! <>
> Greg Kesselring wrote:
>> Hi Mark,
>> Don't know the answer to your question about ketone, but I wouldn't 
>> be too concerned about it.  You're not drinking it.  However, you 
>> should be careful to avoid getting it on your skin if you can because 
>> skin is not an impermeable membrane.
>> Regarding which alcohols have greatest heat output, it's Isopropyl 
>> first, followed closely by ethanol, then methanol which has least 
>> number of btu's per pound.  Here are the btu's per pound of each:
>> IsopropylAlcohol 12,960 btu/lb
>> Ethyl Alcohol 11,570 btu/lb
>> Methyl Alcohol 8,419 btu/lb
>> Note that Isopropyl does not burn clean in most alcohol stoves, so it 
>> leaves soot on your pots.
>> Tinny at Minibull Designs has done some experimenting with a mixture 
>> of Isopropyl alcohol with either methanol (Heet in the yellow bottle) 
>> or ethanol (denatured alcohol).  If you're a tinkerer, you could do 
>> the same with your stove at home and see if there is some blend that 
>> will burn soot free.
>> Probably not worth the bother because Isopropyl and Ethanol have very 
>> close to the same heat output.  On the other hand, based on what 
>> you've found out about denatured ethanol containing large percentages 
>> of methanol, maybe it would be worth finding a mixture that burns 
>> soot free.  You'd have to find a source of Isopropyl alcohol that's 
>> 90 percent or higher.  Most sold in drug stores is 70 percent, the 
>> other 30 percent being water.
>> As far as the two brands of denatured ethanol that you listed here, 
>> it looks like SLK (I thought it was SLX?) would be preferred over 
>> Crown because it has more ethanol and less methanol.
>> Let us know if you find a source of Isopropyl 90 percent or higher, 
>> and what mixture of that and the denatured ethanol produces a clean 
>> burn in your stove.
>> Greg
>> ==================================================================

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