COMMON NAME –Tetrytol 75/25
TYPE – High explosive mixture
DATE FIRST USED AS AN EXPLOSIVE – 1923
COUNTRY OF ORIGIN – USA
COMPOSITION – 75% Tetryl, 25% TNT
MOLECULAR WEIGHT – 270
DENSITY – 1.59 g per ml
NORMAL STATE – Solid
PHYSICAL APPEARANCE/COLOR – Light yellow to buff
INITIATION – 0.19 g Lead azide, 0.23 g Mercury fulminate
SENSITIVITY – Insensitive to friction or shock
STABILITY – Very stable when kept dry, storage over 65o C. (149o F.) causes an oily extrudate to form on material
DETONATION VELOCITY – 7,385 m/s (24,229 fps)
RE FACTOR (BRISANCE) [TNT=1.0] – 1.20
TOXICITY – Toxic if ingested. Releases dangerous levels of poisonous fumes when detonated
MELTING POINT – 68o C.(154o F.)
IGNITION POINT – 310o C.(590o F.)
SOLUBILITY – Insoluble in water
APPLICATIONS – PRINCIPLE USES – Used as both a cast-loaded bursting charge and general demolition charges
Tetrytol is a binary mixture of TNT and Tetryl, usually identified by the percentage of the mixture in its designation. In the mixture of 75% Tetryl to 25% TNT, the Tetryl raises the general power of the resulting explosive while the TNT helps lower the sensitivity of the Tetryl. The Tetrytol explosive can take much rougher handling than Tetryl itself could and was used for demolition charges used in combat zones. Tetrytol is made by melting TNT in a steam-jacketed kettle and Tetryl is added while the mixture is constantly stirred. Part of the Tetryl dissolves in the TNT, the rest remaining in a form of suspension within the mixture. After cooling slightly, the final explosive can be directly poured into munitions or the final forms of demolition blocks. Though more sensitive that TNT alone, Tetrytol is considerably less sensitive that pure Tetryl. Though not recommended, Tetrytol blocks (Block, Demolition, M2) were broken up on board ship and the fragments placed in canvas bags to make a more flexible charge for UDTs to demolish some obstacles in the Pacific Island campaign during World War II. Care was taken to not strike the small pure tetryl boosters that had been cast directly into the demolition blocks.
