I'm having a oven built and need some info about vac line set up as the builder has shown concern about heat transfer and gauge damage ect with the set up i planned to use. As the inside of the oven is made from galvanised steel and the bulkhead fitting (and some other bits ect) are steel will mounting them direct through the outside to inside give heat transfer problems ??. The builder thinks the whole vac set up will get to hot. Will the use of a Sython as in the pics be of any use ??.

Tried them at 65C for an hour and they did not heat up what so ever. 85C for an hour and only the part nearest the wall feels ever so slightly warm if that. 120C for an hour and they get hot to the touch but you can handle them no probs so all should be fine even with gauges.