The Pelican Padded Divider sets are very nice but are pricey. I'll show you how to make your own.
Here are some things you will need: the case you need to create the divider - here I use pelican 1560, straight edge, sewing machine, nylon fabric and velcro which you can get from Ben Franklin or Joann Fabrics, and of course foam - I use 1/2 inch but you can choose whatever you want.
Next cut foam to fit - doesn't have to be pretty - fabric will make it look nice at end.
Here is tricky part: you must sew strips of loop-sided velcro to top of nylon fabric which the bottom of additional dividers can stick to. Use pins to secure in place before sewing. Like this.
Then, using your wife's sewing machine, sew on velcro.
Remember, you must turn velcro and nylon inside out to sew first, so that when you are done sewing, the seams are hidden when you finally turn it right side out for velcro to show. Before turning inside out, use a flame carefully to melt the ends from fraying. Like this see?
Place foam inside, invert the edges and sew close.
To sew outter padded portion, first get roughly twice the length of height of your pelican case. Using your wife's iron, fold the nylon material in half to create a crease. This will help you align the hooked-velcro that will run at bottom edge to stick to bottom of previously created bottom piece.
Use pins again to hold hooked velcro in place before sewing.
Next, sew on hooked velcro on the side facing towards the inside of the case. This is for the partitions you will create later. Notice the breaks in the velcro -this is for the edges of the case where the outer pad will make a 90 degree bend.
Now, take the foam which you have already precut to one of the sides of the case and lay it with one edge on the crease you created earlier. Use marks to know where to sew.
More images and details to come.