Fuse Types and Methods of Joining - Part 1

Below we describe the types of fuses and burn speed used in modern day fireworks. This is very helpful to know especially when it comes to firework safety and firework displays.

Types and varieties of fuses

Fuses are lengths of explosive material, mostly in the form of a thin tube containing the material, used to transfer ignition from the firing point, at a safe distance, to the firework device. They can be linked or joined to carry ignition through branches from one initiation point to several fireworks, or from one firework to another. There are two basic types of fuse-

· Instantaneous: These transfer the combustion at high speed, at many metres per second. This allows the simultaneous firing of several dispersed items from the same point.

· Delay: These transfers the combustion at a slower rate, to introduce a delay effect, e.g. a series of items connected by delay fuse can be fired in sequence at Predetermined intervals. They are designed to burn at different speeds, according to type. Thus any required time delay can be achieved by a combination of the fuse type, and the length of the run.

Fuse Types

There are many different types of fuse found on fireworks, some of the most common types are explained below:-

QUICK MATCH is the commonest fuse to ignite fireworks. These can be single stranded, double or multi – cored. Ordinary black match is made by impregnating a string with black powder slurry. Once dried it burns readily and relatively slowly. When encased in a plain paper or waterproofed paper ‘tube’, however, the rate of burn becomes practically instantaneous.

A protective cap should be provided to prevent accidental ignition when incorporated into a firework and these can come in differing colours. Quickmatch as obtained for general use does not normally have covers.

PLASTIC IGNITER CORD (PIC) is commonly used in the UK but not normally used elsewhere. When ignited it burns vigorously and at a constant rate which makes it ideal for use as a time delay fuse. Two basic types are used in fireworks – FAST igniter cords which are brown in colour and SLOW igniter cords which are green in colour. There is also PW6 which is slate blue in colour and a PIC brilliant blue in colour which is no longer made. All are made by ICI and are waterproof. They can burn under water.

FAST (Brown) burns at a rate of 3.3 seconds per metre (10” or 250mm per sec). It is wound on to reels in 150m lengths and is constructed from a central cotton core around which the incendiary is extruded. This in turn is covered with a clear plastic sheath and is Brown in colour.

SLOW (Green) burns at a rate of 38 seconds per metre (approx. 1”/25mm per second) and is also wound on to reels in 150 metre lengths. It is constructed from a central copper core around which the incendiary is extruded. This in turn is covered with a green plastic sheath and is slightly thinner than the brown fast PIC.

SLOW (Blue) is no longer available. Burned at a rate of 1¼ secs per inch or 49 sec/m.

PW6 (Slate blue) is manufactured the same way as green, looks similar but is a slate blue. Burns slower however, about 4 secs per inch (25mm) or 172 sec/m.

CHINESE SLOW burns very slowly and is unreliable. It will be found on Chinese fireworks as the primary delay. It is constructed from a central core of gunpowder surrounded by woven fabric. This fuse is generally not waterproof and if any damp is in the air it must be waterproofed. This type of fuse is usually replaced during the fusing process if there is any risk of damp in the air.

SPANISH DELAYS Look similar to Pipe Cleaners, constructed from a plastic or fabric outer, this covers a centre core of composition that burns at a constant and accurate rate. These are cut to size according to the length of time required. Spanish Delays are available in all time sequences from 1 second to 1 minute, and more if required..

TAPEMATCH is made by pouring black powder onto the centre of the sticky side of the adhesive tape (sellotape) forming a continuous narrow strip of fuse. Used essentially in the creation of lancework

Summary of Burning Rates:

Quickmatch Instantaneous

Tapematch Instantaneous

PIC Brown 1 sec per foot (3.3sec per metre)

Wasag Green 7 sec per foot

PIC Green 12 sec per foot (1 sec per inch/25mm approx)

PIC Blue 15 sec per foot (1-1/4 per inch)

Bickford 30 sec per foot (variable)

PW6 Slate blue 53 sec per foot (4 secs per inch)