In accordance with embodiments of the present disclosure, systems and methods for safely, and cost-effectively activating a mechanical perforator using a pyrotechnic initiated hydrostatic activating mechanism. The mechanism includes a piston connected to a power rod. The piston is activated by the rupturing of a disc, which separates a first chamber from a second chamber containing the piston. Upon rupturing of the disc, wellbore fluids fill the second chamber forcing the piston to move from a first position to a second position, which causes activation of the mechanical perforator. The first chamber may optionally be filled with a pressurized gas, such as nitrogen or air, to add a boost assist to activation of the piston.