may have a groove machined into it this groove assists in locating rubber o ring 22 which can be snapped into position around disc 20 insert 14 is placed in position in the hole in the interlayer and the second glass ply 3 is placed on top of the interlayer at this point the glass plies are resting on the surface of the o ring 22 the panel thus formed is subjected to a lamination process the panel is inserted into a lamination bag and placed under vacuum so as to degas the panel the panel is then placed in an autoclave and maintained at elevated temperature say from 120 u00b0 c to 180 u00b0 c and pressure 8 to 20 bar for a period of 30 to 90 minutes the rubber o ring is compressed and the inner faces of plies 1 and 3 are pressed into contact with the surface of disc 20 the laminated panel produced can be moved to the location where it is to be incorporated into a glass assembly if it is to be joined to a second panel as illustrated in fig1 the bush 16 the gaskets 18 and the plates 6 are presented to the panel the bolt is passed through the bush and the washers and nuts are screwed onto the bolt and tightened to the desired pressure the disc 20 supports the load and prevents delamination of the interlayer the assembly of fig4 may be constructed in a similar fashion however the insert 14 should be a circular disc made of a flexible material such as a silicone rubber the disc is conveniently a solid disc i e it is a circular.