Nice job.
Never found a use for one, the way I cast. I do use a hot plate to pre-heat moulds.
Usually, I'm casting with 2 cavity moulds, alternately. Would be a PITA, to lift and place the resting mould, between pours.
Larger capcity moulds are used separately and once casting begins, never put down until replenishing the pot. Granted, there is a lapse for the pot to get back up to temperature and mold is resting on hot plate.....but I always keep a propane torch, nearby, and give the mould and sprue plate a few passes before resuming casting. YMMV
So I finally got around to making a cover for my hot plate. I made it at work using 16ga mild steel, a piece of 3/16" rod, and a Chunck of oak I found. I used the belt sander at work to shape the handle. Brought it home and drilled a 7/32" hole in the end I mixed up a small amount of JB weld and used that to set the rod in place. I have a 6" diameter piece of 1/2" mild steel sitting on the burner of the hot plate. I fuigered I needed a 5 1/2" diameter cover so 5.5 X pie gave me the flat dimensions . I then laid out where I wanted the notch to be. Big enough to fit all the different molds I use. I cut the notch, rolled the can, welded the seam, added a cover, ground everything smooth and hit it with a bit of grey primer. I'm about to go try it out for the first time and see how well it works. Walter. 
