Formula: BaNO3
Description: Barium nitrate is used as an oxidiser in both white and green color compositions. When chlorine donors are present in a composition a green color will result from the formation of BaCl+ in the flame. Without chlorine donors BaO will be formed which emits bright white light. Barium nitrate is seldom used as the sole oxidiser in green color compositions. It is usually combined with perchlorates to improve the color and increase the burning rate.
Hazards: Barium nitrate is poisonous and a dust mask should be worn at all times when handling it. Mixtures of metal powders and barium nitrate sometimes heat up spontaneously and may ignite, especially when moist. This can usually be prevented by the addition of small amounts of boric acid (1 to 2%). It is advisable to avoid using water to bind such compositions. Red gum or shellac with alcohol or nitrocellulose lacquer are preffered binder and solvents (also see aluminum).
Sources: Barium chlorate can be made at home from sodium chlorate and barium chloride by recrystallisation. It can also be prepared from barium chloride by electrolysis in a process analogous to that used for preparing sodium chlorate.
Boric acid
Formula: H3BO3
Description: Boric acid is a white powder which is used as an additive to compositions containing aluminum or magnesium and a nitrate. The metal powder can reduce the nitrate to an amide which will react with the metal powder in a very exothermic reaction that can lead to spontaneous ignition of the composition. This process is often accompanied by a smell of ammonia and is most likely to occur with wet compositions. Addition of a few percent boric acid can often prevent this reaction from taking place since it neutralizes the very basic amides forming ammonia and a borate. It is also advisable to avoid using a water soluble binder for these composition. Using red gum or shellac with alcohol or nitrocellulose lacquer is safer. Boric acid will also impart a green color to a flame but is hardly ever used in color compositions since barium compounds in combination with a chlorine donor produce much more spectacular colors.
Hazards: Boric acid is not particularly toxic or dangerous.
Sources: Boric acid is cheaply and in kilogram quantities available from ceramic supply shops. It is also sold in many drug stores at a somewhat higher price, but since only small quantities are needed the price is not really important.
Boric acid
Formula: H3BO3
Description: Boric acid is a white powder which is used as an additive to compositions containing aluminum or magnesium and a nitrate. The metal powder can reduce the nitrate to an amide which will react with the metal powder in a very exothermic reaction that can lead to spontaneous ignition of the composition. This process is often accompanied by a smell of ammonia and is most likely to occur with wet compositions. Addition of a few percent boric acid can often prevent this reaction from taking place since it neutralizes the very basic amides forming ammonia and a borate. It is also advisable to avoid using a water soluble binder for these composition. Using red gum or shellac with alcohol or nitrocellulose lacquer is safer.
Hazards: Boric acid is not particularly toxic or dangerous.
Sources: Boric acid is cheaply and in kilogram quantities available from ceramic supply shops. It is also sold in many drug stores at a somewhat higher price, but since only small quantities are needed the price is not really important.
Calcium sulphate
Formula: CaSO4.x H2O where x= 0, 2, 3 or 5
Description: The trihydrate is commonly known as plaster of paris. The dihydrate occurs as a mineral known as gypsum . Calcium sulphate can be used as a high temperature oxidiser in orange color compositions. Excellent strobe compositions can be made with it.
Hazards: Calcium sulphate is not particularly toxic or dangerous.
Sources: Plaster can be used as is in strobe compositions, but is better to remove the water which is easily accomplished by heating.
Charcoal
Formula: mixture with variable composition.
Description: Charcoal finds widespread use in pyrotechnics. Many types of charcoal exist, each with its own properties. Charcoal made from willow or grapevine is considered great for black powder, while paulownia and pine charcoal are commonly used for spark effects. The particle size and the process used to make the charcoal also play an important role in the quality of the charcoal for a specific purpose. Very fine charcoal floats in air and is therefore sometimes referred to as 'airfloat'.
Hazards: Fine charcoal dust is easily breathed in a dust mask should be worn when working with fine charcoal. Freshly prepared charcoal can be pyrophoric even when not powdered and it must be allowed to stand for a day at least before it is used to prepare compositions with.
Sources: Barbeque briquettes are mixed with clay and are not suitable for making black powder. It will however produce long lasting sparks and can be used for that purpose. Charcoal is easily prepared at home, although it can be hard to get reproducible results. Simply placing some twigs (1 to 2 cm diameter) in a steel pan with a lid and heating it on a camping stove will make reasonable quality charcoal. It is important to make sure you don't heat for too long. Good charcoal looks like the original twigs but black with a brown tinge. It should not have split lengthwise and it should break easily with a sharp snap. The rings in the wood should still be visible. It is possible to tell when the charcoal is done by the smoke emerging from the pan. During 'pyrolysis', the process of heating the wood in the absence of oxygen, smoke will form. After some time less smoke will form and that's the time to stop heating. Leave the lid on the pan while the charcoal cools to exclude air.