Producing plaster components Develop understanding, knowledge and skill within fibrous work

Producing plaster components Aim To introduce fibrous plasterwork Objective To recognise and understand the different materials used in fibrous plastering

Producing plaster components Introduction What do you know? Name two flexible moulding compounds What are laths used for? What is size used for? What is cold pour rubber?

Producing plaster components Introduction Plaster components can be made in a number of ways using different techniques and materials depending on usage, position, size and quantity

Producing plaster components Materials The following plasters are the ones most commonly used in fibrous plastering Casting Plaster is the most common of plasters. It has a variety of uses from ceiling centres to cornices. Fine Casting Plus is the same as casting plaster, except it has an extended shelf life.

Producing plaster components Materials Crystacast is a very hard plaster for models and small casts needing high strength. Crystacal R is a very hard plaster used when making GRG castings. It can also be used for high strength small castings. Herculite 2 is a high strength plaster which is commonly used to make dado mouldings, architrave and other mouldings which may be vulnerable to knocks and bumps.

Producing plaster components Materials Plaster laths 3mm thick used for reinforcement in two gauge casting

Producing plaster components Materials Jute scrim / hessian is used as reinforcement in two gauge casting. Methylated spirit is used to dilute shellac when used as a sealant. Shellac is used to seal moulds, benches, etc. Tallow, melted down and mixed with either paraffin or vegetable oil used as a release agent when casting.

Producing plaster components Materials Splash brush, used to apply plaster to moulds. Casting bowls, used to mix small amounts of plaster. Zinc is used for making profiles for running up moulds. Chopped glass strands are used as reinforcement in one gauge casting.

Producing plaster components Materials Dextrin is used as an additive to harden the face of plaster casts. Tri-sodium citrate / Glue size is used as a retarder, when added to plaster during casting.

Producing plaster components Materials Silicone rubber / cold pour, used to make moulds form original models. Hot melt compound, used for the same processes as cold pour but needs to be heated to make it a liquid.

Producing plaster components Conclusion You should now have the knowledge to complete the following: Name two flexible moulding compounds What are laths used for? What is size used for? What is cold pour rubber?

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