There is disclosed an article which is formed of a solid-phase or liquid-phase sintered product of a metal powder, ceramic powder or glass powder. For manufacturing the article, an extrudable mixture which contains the material powder and a thermoplastic binder is shaped into a continuous filament suitable for use in fused filament 3D printers. The printed object is then invested in plaster or other castable refractory. The invested object is then subjected to heating. The heating process burns off the thermoplastic binder and sinters the powders of metal, glass or ceramic, leaving a pure metal, glass or ceramic object. The extrudable mixture is produced by preparing a material powder, preparing a binder, then blending the material powder and the binder together. The extrudable mixture is then extruded into a continuous filament suitable for use in various 3d printing hardware.