You know what it's like. You read a script, and the challenges hit you. In techs new problems surface. In this ongoing column, we'll explore some of the situations designers and technicians confront and how talented individuals have dealt with them. Many problems are technical: How do we fit this scene into that space? Others are financial: How can we build that prop on this budget? And some are conceptual: What is the visual metaphor for the jumble of emotions this character experiences? People who have been there and back will share their stories. (If you are one of them, write to this column at davi@comcast.net)

PROBLEM: How do you create blood-spewing razors with blades that look sharp enough to kill? For the recent production of Sweeney Todd at CenterStage (set designer John Conklin, costume designer Catherine Zuber, lighting designer Mimi Jordan Sherin, and sound designer David Budries), director Irene Lewis wanted so realistic a production she hired a barber to coach Sweeney on shaving techniques. “The more authentic the blade the better,” says Lewis, “and there was nothing out there.” Properties manager Jennifer Sterns says it was important that the razors be durable and beautiful, “razors to inspire awe.”

SOLUTION: Turn to a pro. Sterns contacted Rafal Szczepanowski, a bio-medical design engineer, who suggested an aluminum alloy that has the appearance of shining metal but is non-ferrous. Nearly an eighth of an inch thick and machined with no sharpened edge, Sterns explains, this kind of aluminum is more like wood but doesn't splinter. He also suggested shatterproof Lexan handles with machined layers. “[Rafal's] expertise made his process so much more calculated and accurate,” says Sterns. “All his material choices are well informed — pins, set screws, composite plastic materials, even the specific aluminum.”

Szczepanowski “carved Sweeny's initials into the knife handles,” adds director of production Drayton Foltz. “He routed out the interior so blood can flow through perforation holes.” Actors pressed the blood-filled pipette in the handle to send blood through to seven delicate holes drilled up through each blade. “We have enough [razors] so we can load them all at the top of the show,” says Foltz. Some are blood razors and some are not. Fight coordinator J. Allen Suddeth had to teach the actor playing Sweeney to manipulate the reservoir and handle razors realistically so that the blood flowed out on cue each night.

Blood, as usual, proved to have its own challenges. “It was most important to get the consistency right to achieve good flow through the razor, but not so runny that it would become transparent and fast-moving on the skin,” Sterns says. “Color and lighting also affected our choice of ingredients.” So did concerns about costumes. “We tried many different liquid soap bases, and for best color, consistency, and wash out found Zout to work best,” Sterns says. “We also used Kodak photo flow, corn syrup, red, blue, and green food dye, and water.” Suddeth's careful choreography also helped protect costumes, which were pre-treated with fabric protector and removed and cleaned as actors came off stage.

Sterns says the shows razors have a clinical look, “which considering their use is a nice touch.” Lewis found them “nothing short of amazing. They are works of art.”