A method of fabricating a frangible material for an occlusive device suitablefor endovasculartreatment of an aneurysm in a region of a parent vessel in a patient,including selecting first andsecond spray devices having first and second nozzle openings and first andsecond adjustableflow controls, respectively. The first and second spray devices are arrangedto deliver dropletsof a first liquid including at least one biocompatible polymer through thefirst spray device and todeliver droplets of a second liquid including a non-solvent for the polymerthrough the secondspray device in an overlapping spray pattern on a substrate at a pre-selecteddistance and a pre-selectedrelative translation speed.
