How to Make a Retractable Blade Theatrical Knife

By Sue Ake
Create a trick knife for authentic stabbings on stage.

Theater costumes and props add interest and color to productions. A stabbing looks more terrifying on stage when the blade of the knife seemingly disappears into the body. A knife with a retracting blade takes just minutes to construct and adds stunning reality to a production.

A retractable blade works well for theatrical stabbings.

Remove the razor from the blade box knife casing. Carefully trace the shape of the razor on the poster board. Cut around the tracing with the scissors. Make several more copies of the razor on the poster board. Cut out the tracings. Glue the tracings together to make a sturdy cardboard blade. Spray paint the blade sliver.

Use black paint to make the knife look more authentic.

Punch a hole in the cardboard blade using the end of the scissors. Insert the cardboard blade into the box knife case. Paint the box knife casing black.

Fake blood oozing out of the stab wound will make the knife appear more real.

Hold the open side of the knife down when on stage to keep the keep the audience from seeing it. Use the slide button to retract the knife blade and re-extend the blade as needed. Make fake blood using corn syrup, water, and red and yellow food coloring for a more realistic stab wound.


Dispose of the razor from the box cutter very carefully.