
Try this
http://www.joann.com …x18-clear/zprd_01971233a/

Cut it a smaller than the foam and put it between the 2 foam sheets..
Ok..that may work...2 foam sheets don't work because the lower part that attaches to the flash is only about 2 1/2 inches wide..you put that little part on the flash and attach with velcro or rubber band and the top just flops over, too top heavy. So your plastic idea may work..