In a process for making refractory articles, such as cores and moulds for use in casting metals, the articles are formed from dies using a refractory material mixed with a thermo- setting resin. The articles are formed with the mixture heated to a softened state and the resin is cured. Thereafter the article has to be fired and problems have arisen with deformation of the articles during the firing process.
With the present invention, the articles, 8, which as can be seen in Figure 2 are mould segments, are bound into an assembly with a flexible refractory tape (15) which shrinks on firing to a greater extent than the articles, and thus pulls the assembly tightly together whereby each article provides support for the adjacent article and prevents distortion. The joint faces between the mould segments are thus held in tight abutment and for pouring metal into the mould, the firing cup is fitted and a coating of refractory slurry is brushed on without removing the tape to seal the assembly.
The process is also applicable to the manufacture of cores to prevent bending during firing.