Does the Oil-Wax Heater (Melter) maintain a constant temperature at the level required?
Yes, but you need to keep notes on the first few batches and mark the dial indicator.
The water jacket provides an even heat and helps provide a regulated and constant temperature, but remember, you should try to maintain a fairly constant room temperature.
A fluctuating room temperature will make it difficult for your thermostat to control a constant water jacket temperature. An insulation jacket can eliminate these fluctuations.
Once wax is at desired temp will it maintain that temp until finish product is done?
You can maintain an even temperature by just setting the dial on the thermostat to a particular set point.
The temperature-sensing bulb is in the water jacket. The reason is that they are very fragile so it is placed in the water jacket to protect the bulb and capillary tube from being hit by stirring or by liquids being poured in, etc. It is also surrounded by liquid making it more sensitive to changes in temperature.
The thermostat turns on and off with changes of + or -, 2 degrees Fahrenheit.
There will be a slight temperature variance between the inner tank and the water jacket but if you insulate it, the difference is very slight. No matter what type of tank you buy, single, or double jacketed, you always want to check the contents temperature and make notes on where the dial is set. This way you always know right where to set your thermostat. You can even place a mark at the setting or settings so that after a short while, you can just turn the knob to the mark.
Because it is a water-jacketed tank, it will maintain a very constant and even heat. The jacket goes nearly all the way to the top of the inner tank so no matter how high the contents are that you are heating, the heat will be evenly distributed (think of a hot water heater).