I made three ADA signs out of the Rowmark "ADA Alternative" material, drilled holes for braille using a .059 bit, used .062 braille beads but my beads/rasters won't stay in the holes. I drilled the holes .036'' deep to make sure they were deep enough. Is there some kind of glue I can use to salvage this job? Because I don't have anymore of the material to do the job over. Thanks! Wayne