My experience with liquid fueled colored flame mines started small. A friend of mine, who is a professional storyteller, wanted to create some "atmosphere" at one of his outdoor gigs. He wanted some colored flames in the background to burn with an "eerie" light. Well, I had a bit of experience with colored flame mines with alcohol and thought I'd give it a shot.
Green mines are easy. You mix a teaspoon or two of the firework chemical, boric acid, in a gallon of methyl alcohol and you're set. The boric acid reacts with the methyl alcohol to give you methyl borate, which is volatile. The boron in the colored flame mine gives it a very pronounced green color. The colored flame mine can be burned in an alcohol lamp or in the open (a Sterno can sort of thing). My buddy used a stainless steel bowl placed in a dish full of sand. Of course, once he had green he wanted other colored flames. But, those were a little more difficult.
In order to get a chemical to make a colored flame, you have to get it into the flame itself. And, unlike the boron, it's either tough or undesirable to produce a volatile metal compound. We fussed with that awhile until we hit on the idea of a wick. A piece of steel wool in the bowl of alcohol did the trick. So now we could produce colored flame mines in a rainbow of colors.
The elements chosen are obvious, but the actual firework chemicals are a compromise among solubility in methyl alcohol, cost, and availability. Turns out that roughly 50 grams per gallon always works. In some cases it doesn't all dissolve, but with calcium chloride or sodium chloride, who cares?
Red: Lithium chloride (actually any soluble lithium salt)
Orange: Calcium chloride
Yellow: Sodium chloride
Green: Boric acid
Blue: (nothing - alcohol burns blue)
Violet: Potassium iodide
The next step was to go large. I had been firing gasoline fireballs out of some mortars I had. Starting with a half gallon, I had gradually worked up to blowing three gallons of gasoline out of a six-inch steel mortar using a charge of 40 to 120 grams of FFG black powder for lift. So why not shoot colored flames instead? Several folks at the "Do-It" fireworks event had a chance to witness my first shots of the half-gallon fireball "Lampare Mines." Upon seeing a daytime video of these colored flame mines, Harry Gilliam coined the phrase "Ghost Mines."
I launched some of these at the Western Winter Blast XII using the following gear:
Mortar: 4-inch inside diameter iron pipe, 2 feet long
Lift charge: Place 40 grams of FFg black powder, a pinch of sponge titanium, and an electric match in a very small zip lock plastic bag. Squeeze all the air out, and tightly wrap it with both clear packing tape and then masking tape to seal it against alcohol seeping in.
Fuel: One gallon of methyl alcohol with 50 grams of firework chemical coloring agent
Method: Fill mortar with alcohol and firework chemical coloring agent solution. Lower the black powder charge into the mortar. If the charge is tightly packed it won't float. From the friendly end of a 50-foot electric shooting wire, fire that thang!
Drawbacks: Typically there is some burning alcohol left behind in the mortar: HDPE and paper don't last too long.
Supplies: I get the methyl alcohol at the local lab supply, or fancy hobby shop, for $10/gal. Ethyl alcohol may work on some but the denaturing agent tends to give a yellow colored flame. I hear the boric acid doesn't work with ethyl alcohol.
No Man's Land: To get a really beautiful sky-blue colored flame, add six grams of copper chloride and 200 ml. of methylene chloride (chlorine donor) to the gallon of methyl alcohol. Great colored flame but it also makes a phosgene byproduct, something you might not want indoors. Any chlorine donor will do that. That is why I shied away from strontium and barium.
References: Unfortunately after pulling this stuff together I found out it was also in Weingart and in an early issue of Pyrotechnica. Well, at least when you reinvent the wheel there is some satisfaction in knowing that it came out round.