An e-match or electrical igniter is an electrical device used to trigger pyro compounds, and is widely used in professional pyrotechnical displays. It is a much safer alternative to visco fuse, black match, and other types of fuse.
Dud shell - shell rises but fails to burst at the proper height and falls to the ground as burning or live pieces. Dud shells have been responsible for many accidents involving children finding them after a fireworks show, thus it is important at first daylight to carefully check the whole area where shells are likely to have fallen the night before.
Dry-rolled is an attribute used to describe the way in which paste or glue has been applied on a sheet of paper before rolling a tube from it. A tube is dry-rolled if the major part of the sheet is rolled onto the former as is, unpasted, and paste or glue is applied at the final turn (at the edge) only.
Dross is a solid by-product of a combustion reaction. For example the residue left behind after a composition has burnt. Dross can be a useful by-product in relation to prime as the red hot dross particles have better ignition properties than hot gases.
When the outer layer of a star, comet or any other mass of dampened composition dries in a way which traps moisture within the still wet core, the star, comet or other mass is said to be 'driven in'. While the mass will eventually dry, it is likely to take several months.
A die is a tool, not unlike a comet pump, used to mould compositions. It consists of a sleeve in which a cylinder slides, under which the composition is pressed.
An example is to make Corned black powder.
Diaper method - is a method of mixing chemicals that are friction sensitive. Compositions that are friction or shock sensitive should never be rammed nor be passed through a screen. Mixing via diaper method is usually done by laying a piece of newspaper on the ground and pouring all the chemicals into the centre of the sheet. Taking one corner at a time you lift the paper and roll the composition into itself.
A silver or gold chrysanthemum with large, brightly colored stars at the tips. The name comes from the Latin word for "jewel". A diadem shells displays both a tail and color at the same time. This requires the use of special stars such as married or tipped comets. In practice most (pseudo-) diadem effects are achived using common colored stars with excess metal fuel, e.g.
Delay chain-fusing fireworks items have their fuses linked by a length of slow burning fuse, such that they are ignited in series. Once the initial fuse is lit, the operator no longer has control of the subsequent ignition of firework items in the chain.
An explosive that reacts by deflagration rather than detonation when used in its normal manner. Deflagaration is a rapid chemical reaction in which the output of heat is sufficient to enable the reaction to proceed and be accelerated without input of heat from another source. The effect of a deflagration under confinement is an explosion.
