I needed a mat that I could use my embossing gun with and I ran across one I could make. First I used very heavy/thick chipboard. This one was the back part of an embellishment pack.
Then I folding the foil around the cardstock, like I was wrapping a present. I taped the flaps down on the back side.
Now I have a great embossing board.
I think the reflective foil helps the powder/gun heat up faster and I don't have to worry about burning my fingers or my table. I also use a wood skewer/tooth pick to help hold my paper in place so it didn't blow away.