SLX Denatured Alcohol vs HEET vs Green (Klean Strip) Denatured Alcohol

Hi, James,

Thanks for taking the time to write down your findings. Very clearly presented by the way.

In your tests, did you measure out the same amount of each time of alcohol for all the tests? And then all of the tests were basically about the same in terms of boil time?

In your testing, did you by any chance measure total time of burn? I’m wondering if any of the three types of alcohol you used might have had a difference in total time of burn.

HJ
Adventures in Stoving

Hello Jim, thanks for commenting!

Here's my test criteria and newfound results.

– SLX and Green DA were transfered into separate Trangia Red Fuel bottles (500ml) as it's easier to pour from

– 1 drop of food coloring was added to each bottle (so I can differentiate the type of fuel being used visually, green for green DA, red for SLX)

– I used a Pyrex 50ml graduated cylinder along with a simple medicine dropper to measure out exactly 20ml of fuel in each test

=====

Test Update:

It wasn't apparent in my initial testing as I made only 1 test within my shop using only 1 stove (a popcan type, not pressurized), I noticed that after a couple more tests, the Green DA does burn sooty, not nearly as bad as using Isopropanol but it does leave traces of black soot behind. The stove was relatively clean until I looked under my pot.

The reason for this is likely due to the type of stove used, I didn't notice it when using a stove configuration where the pot was set very close to the stove (I used a stove designed to work best with pure methanol). However once the distance between stove and pot was increased, it was very apparent that the Green DA burns with a more yellow and orange flame. Since I mostly boil water and carry a homemade MRE with me on trails, I normally use an Evernew Ti DX stove so I used that configuration to redo the tests. Using the Evernew, I noticed some black soot inside the top piece (where you set your pot) and under my pot.

To counter the sooty deposit issue with Green DA, I simply added an equal amount of yellow HEET (methanol) to essentially make a homemade SLX-like product. I've only tested a 1:1 ratio but I'm looking to see just how much methanol I need to add to Green DA to stop it from being "dirty". So my current theory is, you only want to add just enough methanol with Green DA to counter the problem.

Interesting that alcohol with a higher ethanol content burns dirtier than a lower alcohol content.

I haven’t experimented with it, but I know some people add a dash of water to their alcohol to get it to burn cleaner.

I know there’s no difference in boil times between the different types of alcohol you tried, but is there any difference in burn times?

HJ
Adventures in Stoving

"Interesting that alcohol with a higher ethanol content burns dirtier than a lower alcohol content."

"I haven't experimented with it, but I know some people add a dash of water to their alcohol to get it to burn cleaner."

Hi Jim,
Yeah, Sometimes a stove can burn a bit too hot, vaporizing fuel faster than it can be mixed totally with air. So, you get incomplete combustion, usually indicated by a yellowish flame and some soot (generally, unburned carbon or lampblack.) The solution is to slow it down a little. (Though this is rare with methanol, it crops up more with the longer 2 carbon chains in ethanol.) A few drops is usually enough to slow down vaporization a bit, reducing pressure and giving it more time to mix with the air. This is usually more prevalent over 5000' than in lower elevations, though. You can think of it as water molecules displacing alcohol molecules at the surface, hence, not as much vapor pressure, though this is not totally what happens.

Very good research!
First off, you may be wary of skin contact but careful pouring solves this.
I actually like transferring my alcohol to another container. More specifically, I use these bottles the most:
1. http://www.rei.com/product/402026/flat-oval-bottle-4-fl-oz but with a flip cap.
2. or the 0.6L evernew bladder but use a flip cap: http://gossamergear.com/etc/hydration/evernew-water-bladder.html

They’re easier to pour from or you can roll the one up as it’s emptied.

And if cost is a concern, Walmart also has their 12 fl oz HEET copy-cat for 98¢. http://www.walmart.com/ip/Super-Tech-Gas-Line-Antifreeze/19232346
I don’t see it too often but when I do, like last week, I’ll snatch up several bottles. And sometimes I catch them on sale in March for a clearance price of 50¢! At 1 fl. oz per meal; that ~4.2¢/burn.

-Barry

James Marco wrote: > Hi Jim,
Yeah, Sometimes a stove can burn a bit too hot, vaporizing fuel faster than it can be mixed totally with air. So, you get incomplete combustion, usually indicated by a yellowish flame and some soot (generally, unburned carbon or lampblack.) The solution is to slow it down a little. (Though this is rare with methanol, it crops up more with the longer 2 carbon chains in ethanol.) A few drops is usually enough to slow down vaporization a bit, reducing pressure and giving it more time to mix with the air. This is usually more prevalent over 5000′ than in lower elevations, though. You can think of it as water molecules displacing alcohol molecules at the surface, hence, not as much vapor pressure, though this is not totally what happens.

James,

Thank you for that. That was basically what I thought was going on, that the alcohol was probably getting so much thermal feed back that it was vaporizing at such a rapid rate that it wasn’t mixing with sufficient air to burn cleanly. The idea of the water is to slow down the rate of burn a bit.

The big plus of using water to slow down the burning is that water can often be obtained on site — in other words you don’t have to pack it in.

HJ
Adventures in Stoving

Wow great discussion.

I haven't thought about thermal feedback being a factor, now that's interesting. Thanks James Marco for that. Would you think certain stove designs would be more prone to thermal feedback than others? Also how much water do you think would be sufficient to slow down this effect?

Barry, thanks for pointing out those items, for squeeze bottles I have something I purchased form the Coleman section, looks like a bunch of different sized squeeze bottles I guess. However I was not aware of Supertech providing a copy-cat product, that's got my attention now.

James (Nomura),

What if you just played with it a bit? I’m thinking something like a 95/5 alcohol/water mix would slow things down enough that you’d burn a lot cleaner. If that didn’t work, you could try 90/10. 10% water seems like it would slow things down too much though. 3% to 5% would probably be enough.

HJ
Adventures in Stoving

Jim,

The hard part is always figuring out what to start with. My medicine dropper has markings for 1ml and I think that's excessive for a stove, but I need to test it out. 1ml water to 20ml fuel (approx 5% water content) seems excessive but I'll give it a shot, thanks for the starting point suggestion.

Ethanol (or DA with a higher ethanol content) has more energy than pure methanol so I want to be able to make use of its heat potential without getting into the dirtiness so my working plan is as follows…

– measure out how many drops is equivalent to 1ml

– start with a ratio of 1ml distilled water to 20 ml of Green DA

– test burn and tune going up or down on water content by 0.5ml

I want to like Green DA as I feel better using fuels with more ethanol and less methanol, and although this isn't a huge deal with me, the cost per quart is a little less than SLX.

start with a ratio of 1ml distilled water to 20 ml of Green DA

That sounds like a good starting ratio. A ratio 20ml to 1ml is just slightly less than 5%, so I think you’re on the right track.

Do let us know how it goes,

HJ
Adventures in Stoving

What makes you think that there isnt already a ton of water in the denatured alcohol??? There is probably already significant water there, up to 10% is possible.

Cook a bit more with the Green and may see more than soot, you may see a nasty sticky varnish film eventually build up on the bottom of the pot and must be scrubbed off. Quit thinking that this is some kind of reagent grade solvent with only MeOH and EtOH in it , it isnt. Its crap, pure and simple. There is nothing "Green" about it either, just a marketing ploy.

Ethanol
Methanol
MIBK <10%
Ethyl Acetate <5%

Note that only hazardous ingredients are listed, and of those, only those > 1% conc. must be. Keep in mind it was not intended to be burned as a fuel either. These type products are made from by-product waste streams, not reagent grade materials.

Kleen strip green is advertised as a fuel… actually listed as the first thing for it under the title if you've seen the container.

Martin,

Interesting comment about how water might already be present, hmm. One thing I'm not certain about is whether the MSDS of a product has to provide inclusion of any water present in the product or does it only deal with ingredients classified as HAZMAT?

When I performed my tests, if the pot was discolored, I cleaned it up completely so it'd be easier to see changes when I moved onto the next test. Now you got me wondering if the darkening I discovered after using a 25-33% water mix was indeed varnish as I didn't allow it to build up upon each of the tests however you're right that it's a concern of mine since I don't like any build up if I can help it, especially on my better cookware.

The idea of the product being a Green DA I believe is about how the majority of the contents are from using a sustainable and renewable resource to produce it. Whether it's a marketing ploy or just something to make someone feel better, I think some people key into that sort of stuff, especially the "tree hugger" crowd.

For me, I could care less if it was discovered that isopropanol was the greenest fuel produced, I'd still avoid using it at all costs.

your correct, it does say fuel.

My experience is that it isnt very clean burning. It is definitely hotter burning though than SLX. I think a few others have had less fouling complaints. Leads me to believe some batches may have varying amounts of contaminants which lead to fouling.

I had black shiny varnish on bottom of my pot, it looked like a well-seasoned cast iron pot. Never completely came off, most scrubbed off with alcohol though. some left in the surface texture that couldnt be scrubbed.

Only hazardous ingredients greater than 1% conc are listed on the MSDS. Not everything.
Water is not hazardous, and isnt listed.

James,

I wonder how isopropanol would work when blended with water. I’ve heard from guys who say a 70% isopropanol to water mix actually isn’t bad in the soot department.

HJ
Adventures in Stoving

Hi Jim,

You're always coming up with some really good questions for me to think about, so thank you! Please forgive me as I'm about to get very wordy.

Like many, I avoid ISO fuel as much as possible as I've had really bad experiences in the past, however I can't deny the potential for using it since the energy output is much higher than ethanol and methanol alone (and of course denatured alcohol). I've tried many commonly known designs (nothing complex) to see if I could make it work but failed.

As you already know, I'm new to the idea of adding water to alcohol to "tune" the reaction down. I recall watching a video featuring Tinny from Minibulldesigns mentioning how it might work if you use a particular type of stove with a wick, I've never tried any alcohol stove with a wick so that may be something to experiment with in the future. If I were to go ahead with testing, I'm thinking of perhaps conducting a very simple (and cheap) experiment using a tea light cup and an empty tuna can to perform initial testing to see if I can figure out a decent ISO to H20 ratio where it stops leaving sooty deposits. That way if I discolor, or damage either, no big deal.

Searching Youtube, I came across a rather interesting video by BrokenAeroVT at the following link. The author has some great ideas but lacks the proper equipment (like Tinny) to create a solid prototype. I'm impressed that a prototype was nonetheless made despite the author's issues with JB Weld, but I believe that a prototype needs to be constructed in a manner to be able to have repeatable results.
http://www.youtube.com/watch?v=trUy-Ru7Bg8

If you watch the video, the author appears to be very chemically educated suggesting (or stating as fact) that the reason why ISO fuel is inefficient is because it requires 3 times as much oxygen per molecule of fuel than for example, methanol. I can't verify whether this is correct or not but it's not hard to believe at all. I work on cars as a hobby, and we all know that rich fuel mixtures leads to post combustion deposits. Rich fuel mixtures also tend to be cooler in terms of post-combustion gas temperatures so the author may be onto something.

Whether we can resolve ISO fuel's issues or not creates new problems with cooking/heating. More heat output doesn't always translate into a good thing, for example some pots have non-stick coatings on the insides and they might not react too kindly to the increase in heat. There's also the issue of how certain materials may react differently to certain kinds of heat. For myself I choose to use Titanium cookware because it's strong and light, however I know that it discolors easily if temperatures are too high (doesn't damage it but it does turn it rainbow-blue) and Ti cookware isn't the best choice regarding consistent heating. Aluminum is a better heat conductor but copper's even better. Using Ti for example, may have issues with hot spotting (uneven heating) versus using copper and it may become more pronounced with higher heat levels. If you want to just boil water fast then I guess it really doesn't matter.

Getting back to designs for the stove for ISO fuel, I believe most don't use it because the design of the stove needs to be different to have clean-burning results. Water-tuning's fine but I don't think we're using the fuel's higher energy potential. ISO's heat output is significantly higher than using methanol and if BrokenAeroVT's right about it's higher oxygen requirement, I'm wondering if we need to use a carburetor-like mechanism to ensure a proper air-fuel ratio when using ISO fuel in a residue-free manner. Just brainstorming, I would think it would involve a few stages to get the system up and running. Priming it to get the reaction going so that the mechanism can get to the necessary air velocity to draw out the proper amount of fuel on its own.

Questions, Challenges and more Theories:

Q: What kind of ISO fuel sources to be used?
T: I read somewhere about the RED ISO HEET where (according to its MSDS) that the "proprietary additive" is fuel injector cleaner, this is a problem if this is true. I have no other sources for isopropanol with that much of it without being of the medical grade types where it's 91% or 70% with water already in it.

Q: Is all the time and effort to create a working, clean burning ISO fuel stove worth it?
T: I haven't seen a single stove which claims to be a clean burning which uses ISO fuel on the open market, but that's likely due to my limited experience. If you have a use for stove which burns hotter, if you could control the heat output you could end up using less fuel. However this complicates the design of the stove and may not be the best choice for soloists. I'm wondering if it could end up being a good alternative to packing a sealed-gas stove.

Lockon (too many Jims and James here…hope you don't mind), isopropinol is no good as a fuel. It does indeed require a lot of free oxygen to burn. But, without some sort of premixing, and a sustained post combustion, it will always produce a certain amount of soot. Offsetting the heat value, which *is* higher, the incomplete combustion leads to several different molecules and byproducts from incomplete combustion. So, you loose heat value. What you suggest actually requires a presurized burner, preheat tube for expansion/vapourization, a fuel/air mixing chamber (a jet and air intake) and a burner. This sounds exactly like a WG stove with all the gadgets…it is. Indeed, the old Optimus stoves, with a jet modification, run on alcohol (metyl, ethyl or isopropyl) fine. The lack of latent heat in the fuel in comparison to WG makes them rather heavy to carry, though. WG, or kerosene, would be a superior fuel in this case.

The second main objection to isopropinal is that it is highly toxic. The fumes are VERY bad. If you want to play with it some more, make sure you use a hood and vent it. Even small amounts will damage your liver. Methanol and ethanol are nowhere near as bad, but both will cause liver damage…methanol at a much higher rate than ethanol, of course. And, because the burn pretty clean, you get most of the latent heat out of them, unlike isopropynol. I started looking for a catalist but never finished the research in this area. (A lot like the MRE foods, where you simply add salt water to catylize the heating, or, a platnim grid screen…)

Anyway, it *is* true that most alcohols have some percentage of water in them. For ethinol it is roughly 5%. Even everclear has water. This is because they form a eutectic mixture at the boiling point. The water vapor, while not boiling, is high enough to carry over while distilling at the same rate as the alcohol is boiled off, keeping the temperature constant. Soo, it can never be more than 95% pure alcohol.
Adding water while burning increases the percentage of water. Also, moisture laden air will absorb some percentage more oxygen into it. I forget the exact number. But this will also increase combustion due to the increased oxygen availability. Soo, there is a bit more to it than simply slowing things down. For example, your car will get better gas milage just before a rain storm. Same effect due to the increased oxygen availibility. More to it than simple thermal feedback, though this plays it's part, too.

SLX is not a true formulation. More of a mixture of leftovers and what is on hand that will meet the specs. The odd ingredients are a result of the chemical processes used to produce ethanol(well, more of a byproduct) from the petrolium industry. It is just easier not to refine it more to remove them, and, only by law, you understand, it is not possible to drink it without toxic effects. (All drinking ethanol in the US *must* be from distilled fermented sources, not petrolium byproducts.) Soo, it may not contain water in a freshly opened can because it is not generally considered distilled, even though a fractionating tower is a sort of distilling process, just not with water. It's content can vary but should be always above 50% ethanol. Methanol is usually the other alcohol. Even if you could determine a mixture, say 10% isopronol & 90% SLX, the next batch will likely be different. At least Everclear will give you a known starting point, even if it does have water in it already.

I don't bother, I just use SLX. This works as well as any, and does *not* contain various mineral salts that will really screw up a stove (let alone my food and me!)

Wow! I like where this discussion is going! Busy now, but more later…

HJ
Adventures in Stoving

James Marco,

Thanks for your insight and information. You're right, ISO fuel is problematic and not simple to implement well in most alcohol stoves, the latter is what I was concerned about. The sooty deposits alone are an indication that it's releasing more pollutants into the air. Like you, I'm not saying that breathing in post combustion gases from using pure methanol, ethanol or both is healthy but you get the idea. Hiker Jim seems to be curious about the idea of using ISO and I can't blame him. Suppose we could design something relatively simple for ISO fuel which could safely and consistently supply the reaction with 3x more oxygen than typical stoves, I believe we'd reduce the post combustion byproducts significantly to where it becomes feasible to use. Assuming the additional heat produced doesn't wreck havoc on your cookware, we could reduce fuel consumption at the same cost as using pure methanol (since both yellow and red HEET costs the same).

Backpackers are practically synonymous with the idea of simplicity and I believe an alcohol stove, even if it was made to accomodate ISO fuel efficiently, will be anything but. However there might be circumstances where a person may not, for whatever reason, have access to better fuels and may only have ISO fuel (pure isopropanol or rubbing alcohol with more water) to use and I think it's a good idea to know how to deal with it while minimizing the consequences of using it (i.e. water dilution, etc.)

=====

Back to Green DA, while I'm happy to have learned that you can detune the reaction by using water, I'm not convinced that it's a good choice for my setup since there's visible discoloring/darkening of my pot from using it.

To eliminate the problem, I've blended it with either SLX or HEET with the following proportions…

20% SLX, 80% Green DA
or
10% HEET (methanol), 90% Green DA

The new blend would theoretically have more energy producing potential than with either SLX or HEET alone however I think I need to retest using a pot made of a better heat conducting material.

Zelph's Fancee Feest stove burns cleanly with ethanol (I use reagent grade ethanol just because I have it.) Other stoves I tried did not burn cleanly with ethanol.

With isopropanol, soot is generated though.

Do you have a photo of this particular stove?

I don’t know of any stoves that burn cleanly on high concentration isopropanol. I’ve heard of guys buying 70% concentrations from the drug stove and doing OK with that.

HJ
Adventures in Stoving

I have 2 stoves that will burn iso91 clean. The Super Stove with reduced pot support height and the Ring of Fire stove. Photos of these stoves have been posted on Whiteblaze.net, youtube, here on BPL and bplite.com. nobody remembers them, sniff sniff :-) I have a prototype that burns kerosene cleanly. Made that one 5 years ago, posted it on whiteblaze. Nobody is seriously interested in exotic stoves. They want what everyone else is using….alcohol or canister.

Zelph is taking the time to state the obvious, since it's an issue dear to his heart.

We like to differentiate stove performance based on a few finite categories; canister vs. alcohol vs. white fuel, whatever. It's not even close to that simple.

Denatured alcohol (in the U.S.) is about as vague a "definition" as exists.

We don't assume that our propane grill will run on a natural gas supply(vague), we don't try to hook it up to an acetylene tank either usually, or some combination of various gases and call it good.

Ranting as usual, but the point is, in most applications, stove burner performance is *highly* tuned based on the requirements of the fuel, and it's optimal combustion concerns given the application, and if we want optimal performance from "alcohol" we need to consider that.

However, in that vein, I'll say that it's up to the alcohol stove makers to clarify what fuels and conditions are ideal. Cannister stove makers do that, by simply limiting their products to a singular platform.

Personally, I like to design my alky stoves around 190 Everclear, since it's about as clean as it comes, and is on par with a fake cyanide tooth in making you forget (and feel like sh$t in the morning). I tried sunnyside based on the paper, a couple years ago, and wasn't impressed.

"I have 2 stoves that will burn iso91 clean. The Super Stove with reduced pot support height and the Ring of Fire stove. Photos of these stoves have been posted on Whiteblaze.net, youtube, here on BPL and bplite.com. nobody remembers them, sniff sniff :-) I have a prototype that burns kerosene cleanly. Made that one 5 years ago, posted it on whiteblaze. Nobody is seriously interested in exotic stoves. They want what everyone else is using….alcohol or canister."

You have a prototype that burns kero cleanly? Wow…that stuff really requires some fancy foot work. If the photo's still exist, post a link or post a new set here. I just LOVE burnin' stuff…hey, hey… Long as it burns cleanly, the wife may have something to say about the smell…

BTW: White gas and ISO mix fairly well at a 10%ISO/90%WG ratio. It burns clean in a WG stove.