Complete the account of plaster and moulding.
Plaster is sifted into water and left to ______ before mixing. Registration notches that make mould pieces reassemble in one position are ______. For a waste mould, plaster tinted with pigment next to the positive is a ______ layer. Plaster must never be put down a ______, because it sets underwater.
Word bank: slake · keys · warning · drain · cure · seam
Hints
- The first blank is the pause that lets the plaster absorb water.
- The last blank names where setting plaster does permanent damage.
Show the answer
Plaster is sifted into water and left to slake before mixing. Registration notches that make mould pieces reassemble in one position are keys. For a waste mould, plaster tinted with pigment next to the positive is a warning layer. Plaster must never be put down a drain, because it sets underwater.
The last blank is worth stating as chemistry rather than as a rule. Plaster sets by rehydration, so being underwater does not stop it, it sets in the pipe, which is why every plaster studio has a settling trap and a rule about it.
Practise Moulds II: Materials and Procedure
The app has 5 more questions on this lesson, and keeps your place in the course. Sculpture I is free to start.
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