1kg Incendiary Bombs (IB's)
The 1 kg B1E incendiary bomb, consisted of a cylinder of magnesium alloy, with an incendiary filling of thermite. Rivetted to the body was a steel tail with three fins.
Hundreds of thousands of these incendiary devices were dropped on Britain during WW2 and were dispersed from containers that could hold up to 700 1 kg B1 bombs.
These bombs did not explode as such but started to burn by a small percussion charge which fired upon impact. They were dropped in a variety of containers.
The Civil Defence code-name was I.B. (Incendiary Bomb) which had an alloy head.,
Those with a steel nose, used for breaking through roof tiles, were termed 2 kg S.N.I.B. i.e. (Steel Nose Incendiary Bomb) at 13.5in long, and 2in diameter.
The adjacent diagram shows the internal mechanism and components of 1kg incendiary bombs. The inclusion of an explosive charge was relatively unusual in small incendiaries, its main purpose was intended to increase fear within the population, to deter people from dealing with them.
The unexploded ordnance that are most likely to come across today, are these small incendiaries bombs. These devices, or part of them, are usually buried relatively close to the ground level, as they are not heavy enough to penetrate deep into the ground. Saying that, it is not unusual for them to be found in the fabric of old buildings.
The 1kg & 2kg incendiary devices were ignited by impact to the nose and burnt with sufficient intensity to melt steel.
On average, the Army bomb disposal teams deal with forty-five 1kg or 2kg incendiaries in the UK each year.