I don't recall where I saw it, but within the past couple of days I read
directions for making a simple, inexpensive proofing box from a cooler. The
top of the cooler is discarded and the open end of the box goes down over
the loaves to be proofed. Somehow, a porcelain light fixture is affixed
through a hole cut in the center of the box base (now the top of the
proofing box), and a 15 watt bulb is used to provide the right amount of
heat. Personally, I use my oven as my proofing box by putting a pan of very
hot water on the shelf under the rising dough and closing the door. An
alternative method is heating the oven to about 125 degrees a half hour
before you put in the dough to rise and turn off the oven as soon as the
set temperature is reached. My oven beeps at that point, so it's easy for
me. The oven stays just warm enough through two risings.
Ellen