We have a machine we use to glue foam to leather (seat covers for GM), the foam has a special glue that melts to certain temperature. So we bought this machine (one of those used in a dry cleaning), so ... we installed a timer, a thermometer and a pressure gauge, but ... do we need to calibrate those gauges? the timer release the plate at 40 secs, the thermometer always keeps the plate at 140C and the preassure gauge is set to 80 lbs. We are a very small company and the lamination is not a safety issue, is there any way we can say we don't need to calibrate those gauges?