Materials:
Plaster of paris
1 pair Dr. Scholls foot pads with fabric top (cheap ones)
1 tube silicone rubber caulk
plastic food wrap
1 shoe box lid
newspaper
rag strips 1/4 inch wide
Procedure:
Roll newspapers and place in shoebox lid as spacers, leaving space a little wider and longer than your foot. Cover with food wrap to create a waterproof tray into which you will pour plaster and place your foot.
Mix a cup of plaster of paris with water using the directions on the plaster box. Pour into the tray and cover with another sheet of food wrap. While seated, press your afflicted foot down onto the food wrap until your arch has made a deep impression in the plaster. Leave it there and stay still until the plaster warms up (reacts) and begins to set.
Remove your foot, mix up another cup of plaster and pour it into the depression your foot has made (don't remove the top sheet of food wrap). Press a couple rag strips down into the plaster to reinforce the finished product before the plaster sets. After the plaster sets remove the positive cast of you foot and let it dry overnight.
Sand or scrape the wrinkles and rough spots out of the arch. Fill the arch with silicone caulk and press the cast down onto a Dr. Scholls pad. Smooth the excess from the sides with your finger. Let dry overnight.
Peel the cast away from the caulk and you now have a custom made shoe insert that will support the arch and fit into your shoe. It may be helpful to remove the original shoe liner to make room for the arch support. It might take a few tries to get the cast or the insert just like you want it. If you need a little more support, glue some felt to the bottom of the Dr. Scholls pad under the arch area. Glue more than one piece if you need more. I didn't spend more than $6.00 in materials and I can make as many as I want, one for each pair of shoes and boots I own.
Best of all, my feet feel great. I still have some morning pain but it is much, much better now. I had had the condition for two years in both feet and was one who had to limp and walk with support in the morning. I showed a friend in his 70's with the same condition how to make these and he now claims his feet haven't felt this good "since he was in the womb". I am a computer systems analyst, not a doctor, so I certainly can't diagnose anyone's condition. I have found some relief cheaply and wanted to share this with others similarly afflicted.