You can buy the Thin Ez-mount foam to go with your Stampin up stamps. This will work better with the SU foam.
If you use the other ez-mount foam it is a little thicker and will make your stamp unstable. I try this once. And I ended up with using the Thin Ez-mount foam.
You can find the thin foam at
Sunday International Right now they are out of Stock, But it looks like the will have some at the end of Feb.
Here is how you mount your stamps using the
Ez-mount foam
If you have a
Hot Knife you can use it to cut around your Rubber Stamp