Flashcards in Gypsum Deck (12):
What is Gypsum material used for?
model/ die material
What properties does gypsum have?
fluid when poured
compatible with all materials
What products are used for models/dies?
What has highest porosity and particle size?
How is gypsum used to make plaster?
heated at 120 degrees
How is gypsum used to make densite?
boiled in calcium chloride
How is gypsum used to make dental stone?
What are the stages of setting re. gypsum?
1st stage: water becomes saturated with hemihydrate 0.8% sol
2nd stage: conversion of hemihydrate to dehydrate
3rd stage: dihydrate crystalises out
What is setting accompanied by?
exothermic- up to 30 degrees
What is a retarder of gypsum setting?
What is an accelerator of gypsum setting?