I agree with your statements about sealing and GFCI. Both are used.
Submerging was not me first choice, and ultimately i will screw this in like it was designed. (this is a std water heater element).
I chose this because i could quickly move this from bucket to bucket as i decide what works for me.
The only thing my design has that yours does not, is the ability to raise the vat out of the water. I have my stockpots suspended into the waterbath by a system of ropes connected to a block-tackle system. This lets me pull the milk/whey/cheese out of the water bath when the i achieve the desired temp.
What I am struggling with is size. I would like to make a 5Kg wheel cheese (gouda or cheddar or swiss) once a month. That means I need to start with about 12 gallons of milk.
So i am still tring to figure out the best containers for the job.
I have been looking a 80qt SS stockpot
that would be suspended inside a std utility sink
If I ever bump my equipment up to the next level, it will be something like that. In that case, i will be threading the heating elements through the side of the utility sink. I will also control the waterbath temp with a thermostat circuit.
One thing that i have noticed is that in order to get consistancy, I really had to take detailed notes on temperature rates of change. Every batch of cheese i make, i take temperature readings ever 5 min or so. Both the water bath and the milk temps. This detailed information has let me control thermal transfer to the milk in a relatively predictable format.
So, for example, I know for a fact that with my setup, i can take 4 gallons of milk from 48 deg F to 86 deg F in 43 min.
I know that I can take my whey from 86 to 102 in 30min if I turn the heater on for 12 min then off for 10, then back on for 8.
I am thinking, however, that when i do raise my batch size from 4 to 12 gallons, i may go with 2 or 3 heating elements.
Sorry to ramble.