To produce a play on a budget, many play prop masters and production designers turn to making inexpensive props from cardboard. Whether for a small community theatre group, a professional and well-renowned theatre, or a grade-school theatre production, cardboard provides a great medium for play props. You need to begin creation of your cardboard props as soon as play practice begins, to ensure props are carefully constructed, and repairs or fixes made before the play's opening night. Having the props ready early also allows you to use them during practice for actor blocking, so the actors know where to stand on the stage in relation to the props.
Choose the props you require for the play and look online for photos of the objects you need. Use these photos as a reference to draw the prop outlines onto the sheets of cardboard with a pencil, or print out the objects and outline onto a transparency sheet. If you cannot use a projector and have some drawing skills, you can use a grid technique to draw the images for the props. To use the grid technique you will first draw a grid onto an image you intend to turn into a prop and then scale a grid onto a sheet of cardboard in the size you need for the prop.
Mount the pieces of cardboard with duct tape onto a wall. Place the transparency sheet on the transparency stage area of a transmissive overhead projector. The projector shines the image onto the wall-mounted cardboard so you can trace the outlines of the image with pencils. Go ahead and draw the interior lines of the prop piece, if possible.
Remove the cardboard from its position on the wall and begin cutting along the prop outlines. Use a utility knife to produce the cuts and work slowly to prevent sloppy cuts, especially when cutting out curvy pieces. To produce smooth cuts, score the cardboard first along the exterior lines of the prop image. Scoring is using enough pressure on the utility knife to cut through the first cardboard layer. Use more pressure on the second and, if needed, third cutting to cut out each prop piece.
Use the interior lines you drew in step 2, or draw the lines in yourself using your reference photos. You need these lines drawn in at some point to begin painting the props.
Paint the props with acrylic paints that dry rapidly. Use a light paint load on the brush to avoid soaking the cardboard. Work carefully so you don't have to cut out the cardboard pieces again, as you cannot remove acrylic paint from cardboard without ruining the cardboard piece.
Work with one paint colour at a time. Allow each paint colour to dry for a few minutes before continuing to the next colour. If possible, work your way from the background colour to the foreground colours to create a bit of dimension in the props.
Make the props stand upright by creating cardboard right triangles to support the props. Cut out two right triangle shapes for each prop and crease one side of each triangle to produce a 1-inch wide rectangular shape. Apply glue to the rectangular strip, attach the piece to the back of a prop and allow the glue to dry.
Work with a sharp utility knife to make neat cuts.
When cutting cardboard, make sure the surface underneath won't be damaged by the cutting instrument. Scrap cardboard can be used for this, if available.