why not just get mylar and tape it to your walls... double sided sticky tape never hurt any one, just put it up strait and clean and ur done and it will come off with one "hard" pull. lol the only reason u would reenforce your mylar is if its hagning, and u would be better off bying the flexible cloth refective material. glue shit to ur walls is a bad idea unless it really doesnt matter, glueing and using cardboard seems to be a waste of time. imo.