Some pics of my pressure cooker to vacuum chamber conversion. I used a $6 aluminum pressure cooker I found at the salvation army.
I removed the pressure release and tapped a 1/4" NPT hole for a hose barb connection. I then milled a flat area and window to mount some lexan.
Setting up the lid for milling
Milling the window on my drill press and X/Y table
I used RTV silicone to mount the lexan window