This is my scallop base. I love the way it dresses up the card. :)
Here's what you will need: Your Big Shot, standard cutting plates (2), Scallop Square Die, cardstock and bone folder.
Step 1: Cut your 8 1/2" x 11 cardstock in half horizontally so that it measures 5 1/2" x 8 1/2".
Fold in half using your bone folder to make a standard 5 1/2" x 4 1/4" (A2) base.
***This is what I do. You could make it a little less wide, but I would have a little extra than not enough. ***
Step 2: Position the fold of the card UNDER the scallops so that it doesn't cut into the fold.