50 34 u00d7 99 34 by laying them on the vinyl sheet with about 1 2 34 overlapping at the edges of adjacent strips the asbestos backing sheets 50 34 u00d7 99 34 were cut from a roll of armstrong cork co as 422 armotex asbestos sheeting and placed over the wood veneer the edges of the assembly were then stapled together to form the pre builts the pre builts were stacked into books of 10 as described above employing high pressure laminate boards between each pair of adjacent pre builts and release paper adjacent each face of each pre built seven sheets of 20 mil kraft paper were then placed on the top and bottom of each stack followed by a 1 8 34 thick sheet of aluminum nine stacks were placed in a plywood press having 10 openings the press was closed with the aid of a low pressure pump at 200 psig steam at 310 u00b0 f was introduced to the press and the pressure was increased on the press in the 50 34 u00d7 101 34 press area over the stacks of pre builts by the use of a high pressure pump the cure was carried out at 3200 psig maintaining the temperature at 290 u00b0 f for 50 minutes an iron constantan thermocouple was placed in the center of the center book or stack to monitor the temperature the pressure was then increased to 3500 psig and cooling water was supplied to the press and the stacks cooled to 100 u00b0 f before the press was opened after releasing the pressure.