I am thinking about purchasing sheets of 1/4" foam board to permanently mount my movie posters to. This would solve my problem of wrinkles showing up within my frames. Does anyone know what the best adhesive would be for this purpose? I am not a collector of movie posters and I am not worried about a lot of long term degradation. I would like a smooth mount to the board without any bumps and of course no wrinkles. Has anyone done this? I want to do it myself to save on expense so please do not suggest any services. Thanks!