You can construct a simple two-way mirror using the same techniques used to provide privacy or protection from sun and ultraviolet rays in the window glass of automobiles. When positioned over a wall opening the mirror may be used to view activity in an adjacent room. This can be useful when monitoring activity in a storefront from an office area, or to hide a surveillance camera as part of a home security system. Two-way mirrors are often used to monitor and control shoplifting activities where shoplifting is a prevalent occurrence.
Remove glass from picture frame and remove all labels and clean thoroughly with commercial window cleaner. Allow glass to dry completely and wipe any residue from glass using a clean, lint-free cloth.
Unroll and cut to size one strip of reflective glass film 18" X 24," being careful to avoid creases or wrinkles in film. (See Resources.)
Carefully place self- adhering reflective film over glass and smooth into place using a rubber squeegee to remove any wrinkles or creases.
Replace glass in frame with reflective side out. Do not replace glass cardboard or fiber backing in frame.
Hang mirror in front of a small through-wall opening, such as the former location of a medicine cabinet or a through-wall book shelf. If no such opening exists, cut an opening smaller in size than the frame of the two-way viewing mirror, and hang the mirror over it.