Colored Flames

Mankind has always had a fascination with fire. But colored flames are so much more interesting!
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Dedication

This page is dedicated to the memory of the late Larry Lippman, who would have done a better job, but isn't available.
- Dennis Griesser 

 

Cautions

Fire hot!
Fire burn!
Be careful with fire, eh!

Also, be aware that many pyro materials are hazardous!

Please see our additional pyro cautions. 

 

Basic Theory

When a material is heated, the thermal energy "excites" electrons, boosting them up to higher energy levels in the atoms in which they reside. When the excitation potential is removed (or this atom moves out of the hot zone nanoseconds or microseconds later), the electrons fall back to their original energy levels, giving up the energy difference as light.

Since electrons in an atom are "allowed" to exist only at certain energy levels, the amount of energy emitted by a transition is predictable, as is the color of the light that it emits.

This emission of characteristic colored light in a flame has long been used as a "flame test" to give a rough indication of what is in an unknown compound. Fireworks burn larger quantities of interesting chemicals in order to produce desired colors of light.

Sometimes you can produce a desired color with an "atomic emitter", where the electron transitions take place within a certain atom. Other times, a color requires a "molecular emitter", where two or more atoms hooked together in a molecule, provide the characteristic color. (If you see a reference to a material used as a chlorine donor, you know that the color species is a chloride.)

In order to make nice colored flames, using the basic theory of electron transitions, all you have to do is get appropriate chemicals and find a way to get them up into the hot part of the flame. 

 

Liquid Fuels

Liquid fuels provide something of a problem, because the metal salts that we usually want to use to color flame won't dissolve in common organic fuels, which are non-polar. As a result, you should avoid: If you can't get the salt to dissolve in the fuel, it won't color the flame.

This means that you are limited to polar fuels (the more polar the better), such as:

Once you have a liquid fuel that will dissolve your coloring agent, all you have to do is make a saturated solution by dissolving as much of the salt in the solution as you can.

By the way, I have seen some web references that suggest that alcohols burn hotter than the non-polar fuels:

(cooler) kerosene < Methanol < Ethanol (hotter) 

 

Candle Flames

I have seen directions for coloring candle flames by soaking the wick in various salt solutions, or mixing the salts with wax. I suspect that this doesn't work very well.

Years ago, I conducted experiments in this area and came to the conculsion that there was too much visible white/yellow light already in the candle flame. Any color added by the chemicals would be washed out or lost completely.

I have gotten good results, though, with alcohol flames. 

 

Alcohol Flames

This section is based on Skylighter Bulletin #14 (February 3, 2001) and Bulletin #54 (November 26, 2003), wherein Chris Spurrell reported on his experiments with colored alcohol flames.

Chris shared the following formulas:
color fuel color additive cautions
Green Methanol, 1 gallon Boric Acid, 50 g
Dark Blue Methanol, 1 gallon nothing - alcohol burns blue
Sky Blue Methanol, 1 gallon Potassium Iodide, 6g; Methylene Chloride, 200 ml Poisonous fumes!
Violet Methanol, 1 gallon Potassium Iodide, 50 g
Yellow Methanol, 1 gallon Sodium Chloride, 50 g
Orange Methanol, 1 gallon Calcium Chloride, 50 g
Red Methanol, 1 gallon Lithium Chloride (actually any soluble lithium salt), 50 g

These colored fuel formulas can be used in various ways:

Chris also notes:

In addition to the information from Chris Spurrell, I have seen web references that suggest the following:

I will add that it would be best to assume that all of these fuels are toxic or will product toxic fumes. Don't use these indoors and don't get any of the chemicals on your or your clothes. This goes for the color additives as well as the base fuel itself: if Methanol is poisonous to drink, can breathing the fumes be healthy? 

 

Juggling Torches

Since I'm not a juggler, I can't give any personal advice on this. But I have seen juggling information elsewhere on the net...

The standard fuel for juggling is kerosene or white gas. In order to get the metal salts to dissolve, your liquid fuel will probably have to be some kind of alcohol. You can probably use the materials under Alcohol Flames.

I think that it would be best to assume that all of these fuels are toxic or will product toxic fumes. Don't use these indoors and don't get any of the chemicals on your or your clothes.

The alcohols that must be used as color fuels will burn hotter than kerosene or white gas. This will reduce the life of your wicks.

Contamination can ruin your colors. Don't mix colors. Keep separate torches for each color.

Don't use a torch for color that has previously been used to burn kerosene. If you have to do this, clean the torch of kerosene by first burning it as long as possible without damaging the wick.

You will probably find that your torch wicks develop a crust from unused salts.

All of the metal salts used to impart color will eventually corrode metal parts of your torches. You may be able to extend the life of the torches by washing them out with clean alcohol after use, and burning with clean alcohol to clean the wick. You might want to restrict the use of color fuel to just a few special cheap torches. 

 

Fire Breathing

I lot of the materials used to color Alcohol Flames are to a greater or lesser degree poisonous. And even though you're not planning to swallow the stuff, it's probably not a good idea to have it in your mouth for even a lttle while. 

 

Fireplace

Since a fireplace is usually inside a house, your might want to think twice before adding funky chemicals. As for myself, I am willing to use small quantities, on an occasional basis, with a good strong draft to pull the smoke up the chimney.

#1

I have seen commercial products intended to add color to fireplaces: Presumably the manufacturers of these products know what is safe and effective.

These may be a seasonal items for winter and the Christmas season. You are most likely to find them at stores that carry fireplace supplies (think tongs, pokers, and grates), like Home Depot (in season) and BBQ shops.

#2

I found elsewhere on the net instructions for making wood chips that will add color to a fire.

Coloring chemicals:

Procedure:

#3

I enjoy making fire starters by dipping pine combs in melted wax and sprinkling them with Copper Sulfate or table salt. I give them a wick of waxed paper towl material to get started.

I use these sparingly, two or three to a fire, and only with a good draft. 

 

Campfires and Bonfires

As I see it, fires range from the small (fireplace hearth fires) to mid-range (campfires) to the huge (bonfires). If you go on a large group campout, each cluster of tents may have their own campfire, but everybody joins together for a big bonfire.

I write this chiefly to point out that there is a problem of scale. You can toss a few chemical pinecones into a hearth fire and enjoy the colors. But if you throw the same pinecones into a bonfire, the effect is lost in the huge fire.

If you intend to color a large fire, start with fireplace info, but plan on using lots of chemicals and lots of treated material.

You might also want to see our related pages: 

 

Fireworks

Fireworks are a very special case of colored flame. Fireworks compositions are tricky, and it is dangerous to alter them without precise knowledge of what is going on.

Please don't try to change the color of purchased fireworks. Please don't alter formulae unless you really know what you are doing! 

 

Related Pages

You may be interested in these related pages:

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