Here is a quick guide to making your own fly boxes.
1. Go to storage box or plastic box and get some plastic boxes without any inserts or with removable inserts.
2. Go to Parra rubber and get a piece of foam around .5cm to 1cm thick. i have been using 0.5cm.
3. Stencil the outline of the fly box and cut to shape with a pair of scissors.
4. With a sharp craft knife and ruler slice lines into the foam not quite all the way through but pretty close and not quite to each end.
5. glue the foam into the bottom of the box. make sure the glue is waterproof and holds both foam and plastic.
And there you have it one fly box. Here are some pictures of the ones i have made.
This box was procured from Warehouse stationary and its for holding A4 paper