Posters are an easy way to add drama and flair to a room. If you don't want the formal look or expense of framing your poster, you have other options for displaying it besides just taping it to your wall. Mounting your poster on a sheet of foam board will give it a polished look and structural stability without the expense of framing. Best of all, you can do it yourself with just a few simple tools and easy-to-find equipment.
Apply the adhesive. Following the directions on the can, spray the adhesive evenly over the back of the poster and the front of the foam board. Wear a painter's mask while spraying, and work in a well-ventilated area. Allow the poster and board to sit until the adhesive is dry to the touch.
Prepare your work area. You will need a clean, flat surface large enough to hold the poster and the board side by side. Since you may have to trim the poster and board with a knife, the work area should also be one you can use as a cutting surface -- put down protective padding if necessary. Set the poster face down on one side of the surface. Place a strip of masking tape (it should be as long as your foam board is wide) along the bottom edge of the other side of your work surface. Secure the foam board, glue-side up, to the work surface, using a few sticky-side-out loops of masking tape on the back of the board. The board should be positioned so that its bottom edge runs along the top of the masking tape strip. Place another strip of masking tape on the work surface just along the top edge of the board. These strips will help you see where the edges of the board are while you are mounting the poster.
Attach the poster to the board. Pick up the poster with both hands (if it's large, have someone help you) and flip it over so the adhesive is facing down. Do not let it touch anything at this point. Move the poster over the foam board and position it (still without touching the board) so that its edges are aligned with the edges of the board. If the poster is larger or smaller than the board, make sure its edges are all parallel to those of the board, or it will look crooked when mounted. Gently set down the bottom edge of the poster onto the bottom edge of the board -- it should stick immediately. Moving slowly from bottom to top, set down the rest of the poster a few inches at a time, rubbing it gently with your hand to eliminate any wrinkles.
Trim the board and poster if necessary. Using a straight edge and a pencil or piece of chalk, draw a straight lines across the edges of the mounted poster at the point where you want to trim it. Measure the lines to ensure they form an even rectangle. A good way to test for this is to measure the two diagonals formed by the lines you've drawn; they should be the same length. Make a practice cut with your utility knife along an edge of the board, outside the lines you've drawn. The knife should be sharp enough to cut through the board easily and cleanly; if not, replace the blade. Trim the poster along your guide lines, using your straight edge as a guide. Ideally, your knife should move smoothly along the straight edge and cut each side in a single cut.