An apparatus for compressing powders and the like including a head assembly with a distensible elastic platen mounted in a chambered header plate containing a pressurizing fluid. The elastic platen distends in response to the pressurizing fluid. Further, a base assembly includes a rigid platen mounted in a base plate. The rigid platen includes a face with at least one cavity, into which is added powder to be compressed. The elastic platen is aligned with the rigid platen, and during compression, the two platens may be held firmly in contact. The pressurizing fluid pumped into the head assembly causes the elastic platen to deform forming a single distention per cavity. The distensions compress the powder to an optimal density. The apparatus safely and easily compact multiple small samples of explosives and the like into miniature charges.