This easily made tool addresses two issues that can be frustrating when cutting photoetch parts: preventing distortion of the part; and preventing the part from being launched across the room.  It is simply made from an adhesive backed bumper and a piece of acrylic rod, Figs. 1 & 2.  In my example, I have used 3/8” rod.

The bumper is trimmed back at an angle to allow easy access of a hobby knife blade, Fig. 3.  A flat area can be cut in to make straight cuts easier, Fig. 4.  I used an abrasive arbor band to shape the bumper.  The stiff rubber quality of the bumper adapts well to the part, keeping it free from distortion while holding the part to the cutting surface.