is temporarily laid over the plates and then later removed application_number US 66676276 A description the accompanying drawing shows a single figure a device of the present invention in the case of which in the upper part as alternatives a frame and respectively shuttering boards to be inserted for fixing the air tight sheet are indicated considering the drawing it will be seen that reference numeral 1 considers an air box which is connected with a suitable force of suction or vacuum on it there is placed a steel plate 2 which forms part of the enclosure or shuttering which after insertion of the ceramic plates has a hardening material for example concrete cast in it the other shuttering parts are formed by the u girders 3 4 5 with their webs upright the front part of the arrangement is cut away to make its interior visible on the steel plate 2 a mat 6 of elastic material is laid which as suitable openings 7 the openings 7 expose holes in the steel plate 1 the ceramic plates 8 are so placed above the openings 7 that the edge zones of these ceramic plates lie on the edges surrounding the openings 7 in this respect the ceramic plates 8 can be aligned in a suitable manner with respect to each other over the laid out ceramic plates a sheet 9 of.