Joining Techniques Flashcards Preview

AS Edexcel Graphics > Joining Techniques > Flashcards

Flashcards in Joining Techniques Deck (16):
1

Joining techniques
Adhesives (for joining like and unlike materials)
Contact adhesive
Applications

Metals and polymers; unlike materials, e.g. Plastic to wood; general purpose: fabric to most materials

2

Joining techniques
Adhesives (for joining like and unlike materials)
Contact adhesive
Advantages

• able to bond unlike materials.
• bond forms very quickly. so less need for clamping, etc.
• ideal for gluing large sheet materials.
• sold in metal tubes for easy application.

3

Joining techniques
Adhesives (for joining like and unlike materials)
Contact adhesive
Disadvantages

• must be applied to both surfaces and some time must be allowed before they can be pushed together.
• relatively expensive.
• solvent-based so contains harmful volatile organic compounds (VOCS).

4

Joining techniques
Adhesives (for joining like and unlike materials)
Acrylic cement
Applications

Acrylic

5

Joining techniques
Adhesives (for joining like and unlike materials)
Acrylic cement
Advantages

• rapid bonding of acrylics.

6

Joining techniques
Adhesives (for joining like and unlike materials)
Acrylic cement
Disadvantages

• can be difficult to apply and give a neat joint.
• relatively expensive.
• solvent-based so donations harmful volatile organic compounds (VOCS).

7

Joining techniques
Adhesives (for joining like and unlike materials)
Polystyrene cement
Applications

High impact polystyrene (not expanded polystyrene)

8

Joining techniques
Adhesives (for joining like and unlike materials)
Polystyrene cement
Advantages

• strong bond - melts surface of pieces to be joined and causes them to weld together.
• able to use a brush to apply (water- like consistency) and absorbed into joint by capillary action.

9

Joining techniques
Adhesives (for joining like and unlike materials)
Polystyrene cement
Disadvantages

• relatively expensive.
• solvent-based so contains harmful Volatile organic compounds (VOCS).

10

Joining techniques
Adhesives (for joining like and unlike materials)
Epoxy resin
Applications

Most materials including expanded polystyrene

11

Joining techniques
Adhesives (for joining like and unlike materials)
Epoxy resin
Advantages

• high-performance adhesive giving high-strength bonds.
• chemical reaction hardens immediately.
• versatile - can be made flexible or rigid, transparent or opaque/coloured, rapid or slow setting.
• excellent heat and chemical resistance.

12

Joining techniques
Adhesives (for joining like and unlike materials)
Epoxy resin
Disadvantages

• reaches full strength only after a few days.
• expensive
• often requires manual mixing of resin and hardener, which can be messy.

13

Joining techniques
Adhesives (for joining like and unlike materials)
Polyvinyl acetate (PVA)
Applications

Woods (and porous materials)

14

Joining techniques
Adhesives (for joining like and unlike materials)
Polyvinyl acetate (PVA)
Advantages

• gives a strong joint.
• real inexpensive.

15

Joining techniques
Adhesives (for joining like and unlike materials)
Polyvinyl acetate (PVA)
Disadvantages

• surfaces need to be securely clamped together for long periods in order for PVA to harden.
• generally not waterproof (although some brands are)

16

Joining techniques
Preparation

Adhesives require clean and thoroughly prepared surfaces in order for the joint to fully bond. As polymers often have a smooth and shiny surface finish, they should firstly be cleaned and roughened with an abrasive paper before bonding. Metal surfaces should also be degreased and roughened with an abrasive paper. Woods are porous so the adhesive will 'soak' into its surface. Once the adhesive has been applied to the cleaned and prepared surface it then has to cure (harden). It is important that the two surfaces are held in place securely so that they do not slip as this process can take several minutes, or hours.