Here is where art meets science. The mount and envelope are placed into the machine. The glass is slowly heated as the tube is continually turned. As you can see in frames 1 through 6, the glass slowly melts and forms a perfect seal around the mount.

After the mount has been sealed to the envelope, it is placed into a tray to await the next step in the process. Again, there are alot of Western Electric secrets in this process, so we were not allowed to photograph this process either. The un-evacuated tube is placed into proprietary induction furnaces to heat the internal parts to several hundred degrees. The gas is evacuated from the envelope. The tube is tipped off (the evacuation tube is sealed). Western Electric vacuums are higher than any other 300B on the planet. This process not only removes the gas from the envelope, but also activates the filament so that it may begin to emit electrons.

Here we see the evacuated tube being "flashed". This is an induction process by which RF is run through the coils around the tube. The getter ring is excited and releases its material onto the inside of the envelope to form the silver getter.

This is the tube after it has been flashed.