DID IT! No Sew Project: How to recover your outdoor cushions using fabric and a glue gun. So doing this to my ugly old half dog chewed furniture cushions! I actually sewed mine and used heavy duty Velcro on the edges so they can be washed. Two years later
DIY cushions for patio furniture. I didn't have old cushions to cover so I used layers of cheap bed padding foam wrapped in batting. Look here for how to do boxed corners that are not covered well craftapple.