Hammer, wood block, flat head screw driver, ½ round rasp or flat rasp, sanding screen, sanding paper and sanding sponge are the tools we will need to remove the postive cast from the mold.
Stripping A Cast
For a typical TT or AFO cast, the plaster will take around 30 minutes to harden. To check if your plaster is ready, you can try scratching the proximal face with your fingernail; if it easily gouges the plaster, it is not ready.
If there is a drip of plaster hanging over one of the brims you can try breaking it off. If it snaps off with an audible crack, it means that the plaster is ready. This is the 'Snap, Crackle, Pop' test. It is preferable to strip a cast while it is still warm but starting to cool down. If you are unsure if your cast is ready, give it some more time or ask an instructor.
When ready, make sure the cast is cleaned of all the sand and the mandrel holder is removed.
Try to keep the sand in the sand box.
Transfer the cast into one of the mandrel holders along the walls.
Removing the TT negative can be done with a hammer and woodblock. Rest the woodblock against the brim of the negative and then gently hammer away until the negative cast can be slid off.
Make sure the wood block is connecting with the brim of the negative, not the body of the positive cast.
Tap it with the hammer until you feel movement. You should then be able to pull the negative off of the positive.
Using a wood block and a hammer to persuade the negative to pop off the positive cast.
If you can’t access the brim due to plaster overflow, use a ½ round rasp and remove the excess plaster.
Stripping an AFO is a little more labour intensive. You first need to remove the covering over the seam. Imagine the plaster bandage is duct tape.
Then, using a flat head screw driver, you will slowly pry open the cast starting proximally and working distally.
Pry open the proximal seam.
Once the proximal seam is propped open, slowly pry open the toe and foot region working distally to proximally.
Fully open the foot region and pull the negative off of the positive.