Finishes and Plastering Techniques

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Questions and Answers

What is one of the primary functions of surface finishes?

To eliminate the need for maintenance

To ensure aesthetic value only

To protect against damaging reactions (correct)

To increase the weight of products

What happens if the painted surface of a car is left scratched for a long time?

It temporarily enhances performance

It may lead to corrosion and damage (correct)

It requires more frequent washing

It becomes more durable

How do aerospace coatings benefit aircraft?

They increase maintenance costs

They protect against environmental elements (correct)

They improve aesthetic appeal only

They decrease fuel efficiency

What materials are typically used in the preparation of plaster?

Sand and lime or cement Signup and view all the answers

What is NOT a purpose of plastering?

Increasing the weight of walls Signup and view all the answers

What is a characteristic of good plaster?

It should be smooth and paintable Signup and view all the answers

What is one consequence of not using appropriate finishing materials on products?

Increased risk of wear and corrosion Signup and view all the answers

What is one benefit of applying plaster over concrete surfaces?

It conceals uneven surfaces Signup and view all the answers

What is the primary binding medium used in distemper?

Glue or casein Signup and view all the answers

What is the correct order of the steps in the distempering process?

Surface preparation, priming coating, distemper coating Signup and view all the answers

What should be done to previously distempered surfaces before applying new distemper?

Detach the old distemper Signup and view all the answers

Why is painting done on surfaces like wood and metal?

To provide a decorative finish and protection Signup and view all the answers

How many layers of distemper are typically applied?

Two layers, each with distinct colors Signup and view all the answers

What is required for the surface to be suitable for distempering?

It must be dry and cleaned Signup and view all the answers

What should be applied to the surface after it has been prepared and cleaned?

Priming coat Signup and view all the answers

What is a distinct feature of distemper compared to traditional paint?

It can be applied directly on cement without other coatings Signup and view all the answers

What does flaking of plaster indicate?

Poor bonding between plaster coats Signup and view all the answers

What is the main cause of popping in plaster?

Existence of contaminant particles Signup and view all the answers

What depth is typically implemented during the pointing of mortar joints?

10 mm to 20 mm Signup and view all the answers

What is a characteristic of flush pointing?

Mortar is pushed into joints and made flush Signup and view all the answers

Which type of pointing is typically known for superior visual appeal?

Recessed pointing Signup and view all the answers

What is the primary function of pointing in masonry construction?

Aesthetic enhancement and protection from environmental elements Signup and view all the answers

How can the falling out of plaster be prevented?

By proper material selection and workmanship Signup and view all the answers

Which of the following is NOT a reason for plaster falling out?

Use of high-quality materials Signup and view all the answers

What is a primary cause of plaster de-bonding?

Insufficient substrate preparation Signup and view all the answers

Which type of crack is characterized by fine lines resembling a spider web?

Crazing cracks Signup and view all the answers

What is efflorescence on a plastered surface?

The appearance of whitish crystalline substances due to soluble salts Signup and view all the answers

What can lead to hollowness in plaster?

Excess water in the plaster mix or poor workmanship Signup and view all the answers

To prevent crazing cracks, it is important to ensure what condition of the wall before applying plaster?

The wall should not absorb water excessively Signup and view all the answers

Which of the following is a method to avoid plaster de-bonding?

Preparing the plaster properly and ensuring clean substrates Signup and view all the answers

What is the main issue caused by efflorescence appearing on plastered surfaces?

It causes peeling and poor adhesion of paint Signup and view all the answers

What characteristic should good plaster possess regarding its attachment to surfaces?

It should be firmly attached to the base surface Signup and view all the answers

Study Notes

Importance of Finishes

Finishes enhance product appearance and longevity
Finishes protect products from damage like corrosion, wear, and rust
Example: Car paint protects the body from corrosion if scratched
Specialized finishes, like aerospace coatings, influence product performance
Aerospace coatings protect aircraft from weather damage and sun degradation, ensuring safety

Wall Finishes: Plastering

Plastering is a protective and decorative layer for walls or concrete surfaces
It protects from atmospheric effects and enhances aesthetics
Plaster is made by mixing sand, lime, or cement with water
Applications include increasing wall durability, decorating, sealing, and preparing for painting
Good plaster characteristics include smooth, non-absorbent surfaces, water-resistant, and paintable
Plaster should be firmly attached to the base, resistant to shrinkage, fire-resistant, and sound-insulating

Plaster Defects and Solutions

Plaster De-bonding: Plaster coming loose from the wall
Reasons include thick plaster layers, poor substrate preparation, dusty/oily/dry substrate
Solutions include substrate preparation (removing dust/oil, correct substrate prep), applying bonding chemical
Cracks on Plaster: Common problem with various forms
- Crazing cracks: Fine cracks like spider webs, caused by excess fine content in sand or dry walls absorbing water
- Separation cracks: Occur at joints of different materials due to thermal expansion/contraction
- Cracks with hollowness: Due to hollowness in plaster (extra water) or poor workmanship
Efflorescence: White crystalline substances on plastered surfaces, from soluble salts
Prevention includes using construction materials free from salt
Falling Out:
- Flaking: Small loose masses due to poor bonding between plaster layers
- Peeling: Patching of plaster due to bond failure between layers
Prevention through proper materials and workmanship
Popping: Formation of holes/bumps in plaster
Causes include contaminants (burnt lime, other organic matter) in the mortar mix
Solution: Removing contaminants from mortar

Pointing

Pointing is the finishing of mortar joints in masonry (brick and stone)
Implements joints to a depth of 10-20mm
Done using cement or lime mortar
Improves appearance and protects mortar from damage

Distemper

Distemper is a water-based paint that uses glue or casein as its base
Ingredients include chalk, lime, water, and coloring agents
Known as cement paint because it can be applied directly to cement walls
Available in powder or paste form

Painting

Paints are fluid materials acting as protective and decorative surface coatings
Applied to walls, wood, metal, and more for protection and decoration
Painting process steps for new wood surfaces include:
Surface preparation: Clean, dry, remove dust and spots
Knotting: Repair and cover knots in the wood
Priming: Applying a first coat to create a smooth surface
Stopping: Filling nail holes and cracks with putty
Undercoating: Applying subsequent coats
Finishing: Applying the last coat

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Description

Explore the significance of various finishes in enhancing product durability and appearance, focusing on plastering techniques. Understand how finishes like aerospace coatings and wall plastering protect surfaces from damage and improve aesthetics. Learn about plaster characteristics and common defects, along with solutions.