I’ve always wanted to do a bottomless pit but it’s always seemed like more effort than It was worth. I’ve always told myself that if I had an extra two way mirror that I’d build one for sure. That’s not really a valid excuse, though, because I could always make a Two Way Mirror. Bottom line, I guess I’m just too lazy to make this prop, but that shouldn’t stop you because it’s really not that difficult of a build.
Trisha Morse put together a nice tutorial based on Larry Lund’s original build that employs the use of a home made plexiglass two way mirror.
You’ll start by building the support frames for the two mirrors. You’re going to cut a groove in the length of your 2×4 to slide the mirror into. Once you’ve got all grooves cut in your four frame pieces you can screw three of them together, slide your mirror in and attach the final 2×4.
The walls of the pit are framed with 3/8″ plywood that are secured together using L-brackets. Wood blocks on the outside bottom and top of the walls of the pit allow for it to sit on top of the frame with the regular mirror, while the frame holding the two way mirror can sit on top.
This allows the pit walls to run straight into the bottom mirror which is reflecting the two way mirror above, which is also reflecting the pit walls. Since you’ll be viewing it through the two way mirror side, you won’t have to worry about seeing your own reflection.
You can add styrofoam rocks to both the inside and outside of your pit to make it look a bit more realistic and you’ll want to be sure to add a light somewhere on your pit walls to help with the illusion.