PURPOSE: To prevent scatter of refractory sand to out of a vessel without breakage of a pattern by closing pattern inserting hole in the refractory sand vessel with a pattern fitting plate.

CONSTITUTION: In a stuccoing machine, the pattern 3 is inserted from a hole 5a of the refractory sand vessel 2, and after closing the hole 5a with the pattern fitting plate 17, compressed air is fed into the vessel and the refractory sand 1 is floated up with the air pressure, to stick the refractory sand 1 to the pattern 3. Successively, after stopping the feeding of the compressed air, the pattern 3 is taken out from the vessel together with the fitting plate 17. Therefore, while the refractory sand 1 floats in the vessel, the inner part of the vessel is held to, the air-tightening condition, and the refractory sand 1 is prevented from scattering to out of the vessel.