Make a piece of card stock stiffer so you can use it as the canvas for your spray painted art. You can also use the same technique to prepare the card stock for making some stencils to spray paint other surfaces. Heavy Spray Starch, like the kind used to make fabric stiff, works to make the card stock stiffer. A basic craft material commonly used to make paper hard and non-porous, is used to seal off the card stock so it won't soak up the spray paint and become soft.
Things You'll Need
Cork cutting mat
Heavy Spray Starch
2 Heavy books
Place a cork cutting mat on a flat work surface and put a clear plastic sheet over the board to protect the surrounding area. Place the piece of card stock on the plastic covered board and press a small thumb tack into each corner -- these prevent the corners of the card stock from curling as you work.
Spray the card stock with Heavy Spray Starch, like the kind you use on laundry. Apply a thin, even layer over the surface and wait 30 minutes for it to soak into the card stock and dry. Remove the tacks and turn the card stock over. Replace the tacks and spray the Heavy Spray Starch on the other side. Wait for it to dry.
Dip a sponge brush into some decoupage medium and brush a layer onto the card stock. Wait one hour for it to dry and remove the tacks. Turn the card stock over, replace the tacks in the corners and repeat the process on the other side.
Remove the tacks when the card stock is completely dry. Press the card stock between two large, heavy books and leave it there for 24 hours to flatten out any wrinkles from the card stock getting wet. Your card stock is ready to be spray painted.