Trimonite, like amatol is specified as a substitute explosive for shell and bomb loading.
It is composed of 88 percent picric acid and 12 percent alphamononitronaphthalene. The reason for using 12 percent alphamononitronaphthalene is to obtain a mixture which can be melted in melting kettles using not more than 10 pound steam pressure. Picric acid melts at 120 C which prohibits its use as a casting explosive if low pressure steam equipment is the only type available. However, by mixing 12 percent alphamononitronaphthalene with picric acid, the material becomes fluid at about 100 C and can be cast without any trouble.
Trimonite resembles 50/50 amatol in all its characteristics, with the single exception that it is likely to form sensitive compounds with metals. Provision must be made, therefore, that it will not come in contact with metal, such as zinc or lead. It has one advantage over TNT in that there is no danger of exudation.