8. Commonly Used Chemicals in Pyrotechnics: S-Z
Description
This article is from the Pyrotechnics FAQ, by Hans Josef Wagemueller zoz@cs.adelaide.edu.au with numerous contributions by others.
8. Commonly Used Chemicals in Pyrotechnics: S-Z
Saran -- Colour Enhancer, Binder
Saran is another plastic chlorine donor. It is most commonly encountered
in the form of the cling wrap used to protect foodstuffs. It is slightly
soluble in tetrahydrofuran (THF) and will be plasticised by methyl ethyl
ketone (MEK).
Shellac -- Binder
Shellac is an organic rosin commonly used as a binder where a water-
soluble binder would be inappropriate. It can be bought at hardware
stores in the form of lustrous orange flakes, which can be dissolved
in boiling ethanol.
Sodium salts -- Colouring Agents
Sodium salts are sometimes used in place of the corresponding potassium
salts, but this is uncommon due to their hygroscopic nature. They rapidly
absorb water from the air, which can ruin a pyrotechnic composition.
In particularly dry environments they can be used without too much
trouble, and are therefore used in places like Egypt due to the relative
cheapness of some of the salts with respect to the potassium ones. Sodium
salts are also used as colourising agents, producing a characteristic
orange flame.
Strontium salts -- Colouring Agents
Used to colour flames a brilliant red:
Strontium carbonate, SrCO3 -- Colouring Agent, Retardant
Used often for producing red colours, and as a fire retardant in
gunpowder mixtures.
Strontium oxalate, SrC2O4 -- Colouring Agent, Retardant, Stabilizer
As for strontium carbonate, generally, but suffers from greater water
content.
Strontium nitrate, Sr(NO3)2 -- Colouring Agent, Oxidiser
This is the most commonly used strontium salt, because it provides the
most superb red colour available. Best results will be acheived if the
strontium nitrate is anhydrous.
Sulphur, S -- Fuel
Another basic fuel in pyrotechnics, sulphur is used in many pyrotechnic
formulas across the range of fireworks, most obviously in black powder.
It is recommended to avoid the common "flowers" of sulphur, as they
contain residual acid. If they cannot be avoided, a small amount of a
neutralizer such as calcium carbonate should be added if acid is likely
to present a problem.
Titanium, Ti -- Fuel
The coarse powder is safer than aluminium or magnesium for producing
sparks, and gives rise to beautiful, long, forked blue/white sparks.
Fantastic for use in any spark composition, especially gerbs.
Petroleum jelly (Vaseline) -- Stabilizer
Very occasionally used to protect metal powders e.g. iron by coating them
with a thin film of petroleum jelly.
Zinc, Zn -- Fuel, Smoke Ingredient
Zinc metal is used in what are known as zinc spreader stars, which
produce a very nice effect that looks like a green glowing cloud. Also
used in several smoke formulas, due to the thick clouds of zinc oxide
that can be produced.
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