It's been rather slow going because of a lot of competing priorities, but here is a quick update on how my e-kettle has turned out so far.
The sight glass is the 16" model from Adventures in Homebrewing
here. Still need to calibrate and put markers on the glass.
Here is a detail shot of how the sight glass attaches to the 1/4" soldered on spud. It uses a MxFxF 1/4" NPT parker 316 stainless tee, got it on ebay for cheap, but you can get them on amazon too. The sight glass male threads are 1/8 NPT so I had to get a 1/4" to 1/8" NPT reducer from amazon
here. The other end of the tee is for an RTD temperature sensor. Still saving some $$ for the control equipment but have the plug installed so the kettle water tight in the mean time.
The electrical cover is a 1 1/2" chrome plumbing compression union for $6 at lowes. The plug is a 30 amp twist lock 240v with 10-3 SOOW cable. Right now it is just stuck in for the photo, need to get a stainless washer that fits and a strain relief to make it perminent. Would like to solder in a ground lug, but not sure about that part yet.
I was inspired by the heat stick build instructions, but instead of having the gasket pinch between the inside of the cap and the outside of the element flange using a 1 1/4" reducer cap, I used the regular cap with the seal between the kettle and the flange like it should be, nowhere for leaks along the threads! This seems like a major downside to most heating element covers using electrical boxes. It isn't 100% water tight but because it isn't part of the seal it doesn't need to be, just keep out splashes over the side. A diagram should make everything clear.
One plus is that it's easy to disassemble and inspect. Here is the heating element with the union removed and just the nut captured on the heating element flange.
REAAAALLLY looking forward to powering it up and at least running some boil time tests.