While InstaMorph can be quickly molded into different shapes, sometimes it's easier to start with a uniform flat sheet. Fortunately, it's easy to make flat sheets using a cooking trick for rolling dough.

Instructables sponsored a Build Night at Urban Workshop, and supplied us with InstaMorph to play with -- this is one of the ideas we came up with ;-)

Step 1: Supplies

Smooth surface rolling pin. A glass jar will also work, as long as it has a smooth surface (no embossing or labels)
Two spacers. The final InstaMorph sheet will be the same thickness as the spacers. I used a couple of pieces of scrap aluminum, but anything that won't be compressed by the rolling pin will work.
Knife for trimming the sheets

Step 2: Forming the Sheet

Melt the InstaMorph following the instructions on the package.
Place the spacers on your work surface, making sure that the rolling pin will fit over both spacers.
Place the blob of molten InstaMorph between the spaces.
Start with the rolling pin on the center of the blob, then roll back and forth until the rolling pin is riding on the spacers.
To keep the sheet from warping, wait until the InstaMorph has cooled (turned white) before removing from the work surface.
Use the knife to trim the edges as desired.

Remember, you can re-melt and re-use any InstaMorph scrapes.