You dont need to build some fancy cabinet style incubator, you can just buy a big cooler(about 100qt+), line the bottom with heat tape(I use 11" flexwatt), run all the wiring through the drain hole in the cooler, attach a herpstat prop. thermostat. and boom you're done! I also put a spacer between the heat tape and the tubs in mine in the form of a layer of the cheap store bought water bottles and a layer of eggcrate and I also run a small fan in there for air circulation. Mine cost approximately $250 to build including the thermostat and holds up to 6 clutches(I think? I've only ever put 4 in there)
-Powers