Acrylic (plexiglass is one brand of acrylic) cannot tolerate much direct heat. You should never place a bulb on it. The material also warps if there is a considerable temperature differential between one part of the piece and another. Bad idea all the way around.



For heat tape, a proportional controller holds the desired temp the best. An ON/OFF thermostat is good for limiting the high temp on the heater, but the temp of the heater will cycle 4 degrees roughly below the setpoint. Dimmers are inexpensive, but you have no idea where the setting is, and a chamge in ambient air temp will change the temp of the heater dramatically for the same dimmer setting. If using just a dimmer, it is way better to have a substrate or some sheet metal to average the heat out better. Problem is, many people use aspen or wood chips which only insulate and make the bottom of the cage get hotter than the top of the substrate.



My advice is to either go proportional or else a dimmer AND an ON/OFF thermostat.



What is a proportional controller? Big Apple has one (called the proportional model) and Helix are proportional controllers. They pulse the output in small steps to achieve very tight temp control.

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