The temperature is usually in the range of 120 to 160 C according to the type and moisture content of the veneers. It is chosen according to its capacity for the fastest pressing time and its ability to produce a good joint without blisters. Different pressing conditions are used in different countries, and the resin must be manufactured keeping the differences in the conditions of application in mind. There is quite a difference, for exam- ple, between a UF adhesive and glue mix which is capable of giving good joints at 5 to 8% moisture content of the veneer and a pressing temperature of 120 C, and a UF resin and glue mix usable at a veneer moisture content of 0 to 1% and pressing temperatures of 140 to 160 C. The former needs better flow characteristics and faster curing under standard measured conditions than does the latter if optimum pressing times and production schedules are to be maintained. Lower temperatures lengthen the curing time of the
resins considerably but have the advantage that when the cured plywood sheets are taken out of the hot press, they tend to warp less on cooling or drying.