A method of printing a three dimensional article is provided wherein particles are bonded together with chemical bonds having a bond strength of at least 10 kJ/mol. In one aspect, kits for three dimensional printing are described herein. In some embodiments, a kit described herein comprises a substantially dry particulate material (20) comprising an insoluble filler having a first functional group on the surface of the insoluble filler; and a fluid binder material (26) comprising a multifunctional linker having a second functional group, wherein the insoluble filler is insoluble in the fluid binder material and wherein the first functional group and the second functional group can react with one another to form a covalent bond between the insoluble filler and the multi functional linker.