Decide where you want your inserts installed. Measure the case, bag or drawer where they will be placed. Write down the width, length and depth. Purchase enough closed cell foam to fill the space. It will be easiest to use 1 to 3 inch thick foam and make your insert from more than one piece in layers.
Purchase a spray adhesive for foam, such as 3M Super 77 spray adhesive. It can be purchased wherever foam is sold. The foam itself can be purchased from hobby, craft or sewing supply stores. One can will be more than enough for most projects.
Lay your foam out on a level work surface. Using your measurements, cut a piece of foam large enough to fill the bottom of the space you wish to build an insert for. Use a permanent marker to outline the piece. This will be your insert base.
Cut the insert with a long-bladed craft or utility knife. To make the edges as straight as possible use a ruler or other straight edge to cut against. Apply steady pressure to the straight edge to hold it firmly in place and drag the blade along its edge.
Use the insert base as a pattern to mark and cut enough foam pieces to fill the space you are making the insert for. Make sure to cut the edges with the straight edge for best results.
Use the marker to outline the items you wish to store in your insert. Lay the items on top of one of your foam pieces. Make sure to leave enough space between for the foam to keep them separated. Use the utility or craft knife to cut out the outlines of the items. Try the insert by inserting and removing the items one at a time. Trim excess foam to make the items fit well wherever necessary. Cut as many pieces as needed to fully cradle the items.
Glue the base and insert pieces together. Save one foam piece to place over the top for added protection. Adhesive-backed Velcro can be used to hold the foam pieces onto the top or bottom of cases or bags for added security.
