Process for producing cylindrical reinforcing fibrous molding

A process for producing a cylindrical reinforcing fibrous molding, comprising the steps of:

• sealing openings at opposite ends of a porous cylindrical mold which is formed from a shell sand and has permeability, covering the outer peripheral surface of said mold with a thin film having permeability, immersing said mold into an aqueous solution of a molding material containing at least carbon fibers and an inorganic binder, and depositing said molding material onto the outer peripheral surface of said mold through said thin film by applying suction within said mold to form a molding blank;
• pressing said molding blank against said mold to adjust the shape of said molding blank;
• heating and drying said molding blank;
• placing said mold into a firing furnace in an air atmosphere to completely burn off said thin film and completely disintegrate said mold by heating the furnace to 330.degree. to 480.degree. C.;
• and
• heating said molding blank in an inert gas atmosphere to partially bond said carbon fibers with said inorganic binder.

A process for producing a cylindrical reinforcing fibrous molding, comprising the steps of:

• sealing openings at opposite ends of a porous cylindrical mold which is breakable by applying a pressing force to the outer peripheral surface at least at one end thereof, covering said outer peripheral surface at the one end, then immersing said mold into an aqueous solution of a molding material containing reinforcing fibers and an inorganic binder and thereafter, depositing said molding material onto the outer peripheral surface of said mold excluding the covered portion by applying suction within said mold to form a molding blank;
• pressing said molding blank against said mold to adjust the shape of said molding blank;
• heating and drying said molding blank;
• applying a pressing force to the outer peripheral surface at the one end of said mold which has not been subjected to the deposition of said molding material due to the covering of said one end to break the mold;
• removing the broken mold from the molding blank;
• and
• heating said molding blank to partially bond said reinforcing fibers with said inorganic binder.