Share 'Makeshift Tempering Machine'

I was thinking of getting one of these:http://www.ebay.com/itm/85-2-Magnetic-Stirrer-Hot-Plate-Digital-Thermostat-300w-Heating-2000-rpm-/350527518368#ht_1652wt_1165 as a makeshift tempering machine.I plan to put a water bath on the hotplate and put a pot in the water bath.I would be using it at home to make small batches of chocolate for holidays and such.Can anyone think of a reason that this wo…