Make: Volume 74

Matt Merkel Hess, Adobe Stock - Vjom, Caleb Kraft

After about 10 minutes, reinforce the cast with

plaster-gauze bandages. Add salt to the water

for dipping the bandages to speed drying time.

In Figure

D

, you can see I’m also holding a hair-

dryer to speed the drying process.

After the plaster gauze stiffens, carefully

demold the cast from your face. Alginate starts to

break down within 12 to 18 hours; best practice is

to make your next mold within 4 hours.

2. PLASTER POSITIVE

The plaster-backed alginate cast should be quite

stiff, but it can be backed with more clay so that

it doesn’t bend or deform. Putting this all in a

cardboard box will give ...