Take the new foam piece that you purchased and again use the old material as a template. Since the foam is hard to write on just use a Sharpie to rough in the dimensions. Now cut the foam to the correct size. I found that the foam cut very well with a razor knife while on the concrete floor. I have also seen several people use kitchen knives or electric knives. That is really up to you and you could probably even use scissors if you had to.
Note: The foam hasn’t been cut yet in this picture.
Now that all of the pieces are cut we are ready to start assembling the seat. We will be using 3M spray adhesive to get the foam to stick:
Take the foam and place it bottom side up next to the seat base which needs to be right side up. Spray the adhesive liberally to get a good coverage. Wait about 3 minutes and then stick the two pieces together. Be careful to get the foam lined up well with the edges though.
Note: This picture is just showing the coverage of the spray adhesive on the foam.