Instructables
Picture of The Spirit Lantern (Green Fire 2.0)
050-sm.jpg
Green fire is ubiquitous on the web, and making it is remarkably straightforward - provided you are not led astray, as I was, by ... let's call it poetic license.

Now, after having had a rather disappointing Halloween at chez Green, when I read that a purported "chemistry teacher" found using isopropyl alcohol, rather than methanol, resulted in "a fire that alternated from orange to blue to green" and that it was "pretty cool," I now understand that to mean "after the third whippit, the normal blue and orange flames of the rubbing alcohol looked kind of green. Then I passed out."

The rules of making green fire are as simple as they are inviolate:

1) use methanol

2) add boric acid

The reason for these rules lies in ... chemistry! Here is the chemical equation for the boric acid/methanol reaction:

H3BO3 (boric acid) + 3CH3OH (methanol) --> B(OCH3)3 (trimethyl borate) + 3H2O (water!)

A very small amount of the boric acid is transformed into the trimethyl borate, but as the flame of methanol burning is a very pale blue, the borate compound easily overwhelms it.

I found that I was dissatisfied with the usual approach of making a puddle of liquid and setting the puddle on fire. First of all, the fuel is used up quickly. Secondly, it's hard to control and makes a big mess. For these reasons, I decided to make a small lamp for my green fire for a more controlled, portable and neater illumination.

For this instructable, you will need the following:

* Methanol (Heet - yellow bottle - is an easy source of this) $2.00
* Boric acid (you can find this in the hardware store as an insecticide, but I ordered it through a pharmacy to ensure that the product was not overly contaminated with unwanted chemicals) $5.00
* lamp wick (small round is easier to work with than large flat variety) $2
* small, "sampler size" jam jar
* an electric drill with a drill bit slightly smaller than the diameter of the wick
* (optional) a small hurricane lamp for a votive candle (I found one for $.50 at a thrift store)
* (optional) the metal holder from a spent votive candle

Safety notes:

Alcohol is flammable, and alcohol vapors are explosive if concentrated and lit. Use good sense. One of the reasons for the small jam jar is that only a small amount of alcohol will spill if the jar is dropped and breaks. Also, try not to get methanol on your skin, as it can be absorbed through the skin, and is not nice. Never drink methanol. It is toxic, and cannot be made "untoxic." Think *permanent blindness*.

Boric acid is fairly innocuous, but inhaling large amounts of it (or swallowing it, or getting it in your eyes, etc) will not feel nice.

Green fire produces a white "smoke" that is actually diboro trioxide. It's (evidently) fairly harmless, but makes a mess. The Spirit Lantern is best used outdoors.
 
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The Green Gentleman (author) 2 years ago
For the record, I am aware that the chemical equation above is not properly balanced. Unfortunately, I seem to be having trouble with the editor function on the site. The correct formula is as follows:

H3BO3 (boric acid) + 3CH3OH (methanol) --> B(OCH3)3 (trimethyl borate) + 3H2O (water!)

Also, on one of the later pages, I write that you should use sandpaper to remove pain. I sincerely apologize for this misinformation. No amount of sanding will take away the pain. However, it can be helpful in removing paint. Again, the editor function is preventing me from correcting this typo.
pgach16 hours ago

Illinois Cub Scouts Burned in Chemical Explosion

http://www.nbcchicago.com/news/local/illinois-cub-scouts-burned-chemical-explosion-279886642.html

The Green Gentleman (author)  pgach15 hours ago

That children got hurt doing this is very sad. However, for the record, I stated in the warnings on page 1 that "Alcohol is flammable, and alcohol vapors are explosive if concentrated and lit." If you have some thoughts on a safer way to do this, please make your own Instructable - I will be happy to link to it. I will say that, when it comes to pyrotechnic-related accidents, the CPSC's latest data shows that over 11,000 people were injured using professionally-manufactured fireworks in 2013. That might be a more pressing issue on which you could spend your time.

jjj67818 days ago

cool, but there is an easier an safer way to get a green flame by throwing green sparklers in a fire :) I'm still going to try it though 3:)

dococ2 years ago
Erm...Methanol is also toxic. http://en.wikipedia.org/wiki/Methanol#Toxicity
Maybe you should try Ethanol.
Burning methanol won't hurt you unless you drink it. Probably is safe enough for that use as is ethanol and the solubility of boric acid is much higher.


The same doesn't hold true about the boric acid and you may realize years later.
pmendonça dococ9 months ago
I'm a chemical engineering grad student and work with research in nano catalysis with the oxidation of alcohols. Well...I've been instructed by my research group and in regular class to handle methanol in a fume hood due to it's high toxicity, INHALING the vapours cause blindness and drinking it is lethal in small doses.
As you may notice putting something on fire warms it up, in other words it gets more excited, thus has more energy to "break" the atmospheric pressure holding it in liquid form, aka MORE VAPOURS.
And someone said that it's result in combustion is also CO2 + H2O but nature is a bitch and it's never perfect. There is also methanol being spit up into the air you breath. Methanol is highly volatile, so much so that it condensed and cooled water around a beaker of methanol at my lab, btw it was about 27 Celsius (80F)
pmendonça dococ9 months ago
I'm a chemical engineering grad student and work with research in nano catalysis with the oxidation of alcohols. Well...I've been instructed by my research group and in regular class to handle methanol in a fume hood due to it's high toxicity, INHALING the vapours cause blindness and drinking it is lethal in small doses.
As you may notice putting something on fire warms it up, in other words it gets more excited, thus has more energy to "break" the atmospheric pressure holding it in liquid form, aka MORE VAPOURS.
And someone said that it's result in combustion is also CO2 + H2O, great job reading about complete combustion, but nature is a bitch and it's never perfect. There is also methanol being spit up into the air you breath. Ethanol is hard to find over where u live? Is it worth going to the hospital over it?
The Green Gentleman (author)  pmendonça2 years ago
True. That's why I gave the warning in the instructable. I used methanol because it's easier to get than pure ethanol. As I'm not into racing or "illicit" chemistry, I just needed a small amount. It's true that triethyl borate is also flammable, but I haven't tested it yet. I tried to minimize the danger of the methanol by making a very small lamp rather than the "pour it everywhere and light it" method.
I disagree with you, methanol is never safe to burn. But, fortunately you are unable to purchase methanol. What you are purchasing is "methylated spirits" which is approx 95-96% ethanol, ~2-3% water, ~1% methanol and less than 1% benzene. It is completely safe for burning. Also, rather than looking for "boric acid" it is much easier to purchase borax (tetrasodium borate) as it is lower toxicity to humans. Also, if you add a very small amount of water(say 1 part in 5) the borax will completely dissolve giving a much more intense flame.

Also, you comments about flame colour reasons leave a bit to be desired. For more info about flame atomic excitation and colour emission go to http://en.wikipedia.org/wiki/Flame_test.

You comment that your candle gives too much B2O3. Add less, the amount that will give a really strong colour(high molar extinction) is about a teaspoon (5g) per cup (250ml), any more is just dangerous and wasteful.

Source: I'm not a chemistry teacher, I'm a chemistry professor!
The Green Gentleman (author)  sgooding12 years ago
Thank you for your input. However, Heet Gas-Line Anti-Freeze is, in fact, almost pure methanol. Here is the MSDS for the product I recommended:

http://www.deltaindustrial.com/MSDS/FuelsLubesAntifreeze/HeetAntifreeze.pdf

The products of combustion for methanol and ethanol are the same: CO2 and water, possibly a small amount of CO.  Unburned alcohol vapors should be minimal.  Still, it's always better to be safe than sorry, which is why I recommended that this lamp be used outside.

I don't believe that I addressed the reason why the fire is green at all, so I would imagine that my non-existent comments leave everything to be desired.

If you want a nice green (boron-shade) flame, borax is not the way to go. The sodium component of borax, which emits a yellow color in flame tests, tends to outshine the green of the boron. Since we're quoting Wikipedia, here's the opinion shown there regarding the use of borax in pyrotechnics:

http://en.wikipedia.org/wiki/Borax

Regarding the wastefulness of my boric acid use: I would be far more concerned about someone drinking the methanol in the mixture than drinking the boric acid in the mixture. That's why I recommend that one not drink it.

Last but not least, the LD50 (median lethal dose) for boric acid is considered to be 5g/kg body weight (Merck index, via Wikipedia).  The LD50 for borax is considered to be 4.5g/kg body weight.  For reference, the LD50 of table salt is 3g/kilogram.  Therefore, in order of toxicity, from least to greatest, we have: boric acid, borax, table salt.
You seem that are still missing the point. You don't need to drink the mixture. Not much people with common sense is expected to drink it.


In the long term will harm you just breathing near the candle which is something much less intuitive. And yes, you won't die the same week or even notice for years, which doesn't mean that you didn't get hurt.


For reference, table salt won't damage your reproductive capacity, boric acid and its decomposition subproducts will. And you won't notice.
The Green Gentleman (author)  dococ2 years ago
Actually, I think you're missing the point. The study you referenced, which I read in full, discusses very high levels of boric acid intake - on the order of 1/2 tsp of boric acid (scaled up to human quantities), taken internally, for nine weeks straight. Even at this level, there was no change in the subject.  It would take nine times that amount to achieve the type of worst case scenario reproductive system impact depicted in the study.  This is way more than you could possibly "breathe in" comfortably.  You would need to concentrate and huff the fumes over and over again for weeks to experience the effects discussed.  AND to top it off, I specifically state that this lamp is best used outdoors.  What are you not understanding here?  My concern would be that someone would leave boric acid where a child could get at it.  Also note, that the bottle of boric acid I use and recommend has a child-proof cap.  Unless you have new information to share, please move on to bigger and better issues.
The Green Gentleman (author)  dococ2 years ago
Thank you for passing that along. I'm not sure that this really applies here, though. In reading the study you site, the dosing of rats ranged from 400 mg/kg (for the 9000ppm dose) down to 44 mg/kg (for the 1000ppm dose). At the low end (and I'm estimating a bit here), this would be equivalent to a 120 pound human eating about 1/2 tsp of boric acid. What's more, the person would have to do so every single day for 9 weeks to reproduce the study's results on themselves. This would put them in the "no observable effect group (if this person were a rat). I tend to err on the side of caution with chemicals, but this seems to be a bit much. Were you trying to be helpful? I notice that you've only just signed up for instructables today, and have only posted this one comment.
Well, you registered yesterday and have the same number of comments than me. Are trying to discredit someone's post concerned about a potential risk when pointing to a directly related scientific article (of lots of them)?



Probably you know that boric acid in methanol is burnt for a few seconds to use as flux when brazing silver jewlery as I do as a hobby and even when is considered safe there is plenty of warnings in these products about the boric acid toxicity. (The methanol is way much more toxic if you drink it, so no, they are not expecting you to drink it)



Boric acid also was used in the food industry in minute quantities as sea food preservative until the middle of the last century when was banned for that use due to its toxicity.



I just won't use regularly a candle with boric acid indoors. It's too cool that I've done it too many times before knowing about it. Better safe than sorry.
rayj0007 dococ2 years ago
dococ,
Thanks for pointing out this information. It allows people to make informed decisions about the level of risk they choose to accept.
noire dococ2 years ago
meh. TLDR.

green fire! awesome.
jennyross1 year ago
Wow... Thanks ! I like To do this types of experiments especially with chemistry.. I'm in love with Acetate .. I would love if you share something that i make out of acetate ... because my father has a company for bulk production of Acetate - http://www.tatvachitan.com :)
The Green Gentleman (author)  jennyross1 year ago
Workin on it!
Oh. Thank You For The Kind Reply . Have A Beautiful Day
nnagdy1 year ago
can i use borax insread of boric a ?
The Green Gentleman (author)  nnagdy1 year ago
Yes, but because of the sodium content, the color is going to be somewhat overwhelmed by the sodium orange emission.
darkrafts1 year ago
thank you!
great instructable. found out you can actually buy this chemicals(including the methanol) in a chemical shop in my country.
The Green Gentleman (author)  darkrafts1 year ago
Thank you, and glad to hear it!

Side note: this guy has pages devoted to finding chemicals in everyday places: http://hyperdeath.co.uk/chemicals/ 

This is not my site, and (to be a little weasel-y) it's up to you how you choose to use this information.
slenderboy2 years ago
where is the video
Mtalus2 years ago
I add boric acid to my pulse jet fuel for the same effect.
The Green Gentleman (author)  Mtalus2 years ago
Wow. That sounds kind of awesome!
keriksen12 years ago
What would it take to make the flame blue?
The Green Gentleman (author)  keriksen12 years ago
Actually, methanol burns blue all by itself.
Bulish, not really blue as in The Goblet of Fire...
JOE19032 years ago
This just screams zippo fuel ....
pculbert2 years ago
Nice instructable! I wonder-- if you put a couple of drops of mint oil in the methanol/timethylborate solution--would it smell like mint when it burns? I'm going to try it!!!
The Green Gentleman (author)  pculbert2 years ago
Thanks! I appreciate the props!

RE Mint: I'm no biochemist (or chemist for that matter) but I would be a little leary of adding other chemicals to the mix. Mint oil may very well react with the trimethylborate, and while such a reaction could be harmless, it could also be very nasty. Many essential oils are methyl variants. I personally wouldn't mess with it. My two cents.