Iris ..
I'm not sure what you are looking for in a proofing cabinet, the attributes
of professional cabinets vary.
I built my own out of plywood, just a plain box with full front door, small
glass window in the door, with a thermometer attached against the window on
the inside, all very inexpensive and simple. It could be lined with tinfoil
but I didn't bother. Dimensions are (internal) 19 inches tall and wide and
about 17 inches deep, pretty much a cube. A 100 watt long life light bulb
supplies the heat, and a cheap ($7.00) thermostat sold for use with
electric baseboard heaters supplies the control.
I use it to proof dough/bread, make Kefir and yogurt, and other things that
require controlled heat. I could hatch eggs in it if I wanted to as well I
suppose, all in all a rather useful thing that cost less than forty dollars
to build out of scrap plywood. Any handyman could build it for you if you
don't have the skills.
A glass of water supplies humidity if found necessary, and other
refinements could be added.
bar.
Barrie J. Lax
Ottawa, Ontario
Canada