A process for producing a hollow profile node of a Fiber-reinforced plastic for the connection of hollow profile members of a frame member

A process for producing a hollow profile node (1) of a plastic-fiber composite for a frame element, particularly for a frame member of a motor vehicle, comprising the steps of - generating a soluble core (9) which is adapted in terms of its size and shape to an inner contour to be formed of the hollow profile node (1), - at least section-wise depositing a fiber reinforcement embedded in a thermosetting or thermoplastic matrix, on an outer surface of the core (9), - hardening of the matrix with the embedded fiber reinforcement, and - removing the soluble core (9) from the interior of the hollow profile node (1), characterized in that a water-sand core is generated which is removed after curing of the matrix and the fiber reinforcement by the application of water from the interior of the hollow profile node (1) and the sand core of quartz sand and a binder is prepared, and that as binder a water glass-ester binder is used, wherein the water glass acts as a binder and the Esterzusatz as a curing agent and that for producing the soluble sand core (9) a sandy binder mixture is fired in a heated mold (4) and are formed by removal of water salt crystals in the sand-binder mixture to be cured in a boundary layer on the heated mold (4), and that to accelerate the curing of the sand binder mixture is additionally charged after closing of the mold (4) with hot air.