Body part casts are a great way to preserve a part of your likeness as a keepsake or for the purpose of creating prosthetic extensions. There are many ways to make body casts, but the best way to create a detailed mould of the feet is by using a sensitive dental alginate.
Prepare your feet. Thoroughly wash them and remove as much body hair as possible. Leave each foot slightly damp (though not glistening with water) as you get ready to mould it.
Mix dental alginate with water according to the instructions on the package. Place the powder in a mixing bowl and slowly add the water to it. Mix thoroughly with a spoon. Mix just enough alginate to fill the container, and do one foot at a time. The mixture will have some colour to begin with (perhaps green of lavender, depending on the manufacturer), but it eventually will change to white. Once this happens, it will set in just over a minute, so be ready to start moulding immediately.
Pour the alginate into the aluminium baking pan.
Submerge your foot quickly in alginate. Wiggle your toes a little to let the mixture flow between them. Stop moving your foot after 10 seconds and hold it motionless until the alginate sets. The alginate is set when the top of the liquid in the container is firm and you feel it fully separate and pull away from your foot.
Remove your foot, pulling your foot carefully out of the alginate. The material will be firm and flexible, and pulling out will be a bit like removing your foot from a thick rubber shoe. If you can't get your foot out, create an incision in the alginate over the top of your foot using scissors, stretching from your ankle to your toe.
Let the alginate fully cure. This will take several days; consult the alginate package for the manufacturer's recommended time.
Mix enough plaster of Paris in a mixing bowl to fill the foot mould, and pour it in. Fill to the top of the mould hole. If you want your cast to be attached to a flat base, pour enough plaster to cover the top of the mould and fill the container above it at least 1/2 inch deep. Let the plaster set and harden according to the manufacturer's instructions. Pop any air bubbles that rise to the surface as the plaster dries.
Remove the alginate and plaster from the baking pan. Slowly turn the pan upside-down. If the contents don't slide easily out, break the pan and tear any aluminium away.
Cut through the alginate to remove it from the plaster mould. Cut away large chunks with a craft knife and peel away from the mould. Work slowly to avoid damaging the cast.
Repeat all steps with your other foot.