18. Adhesives and fixings

Question 1

What are the different types of adhesives?

Answer 1

• polyvinyl acetate (PVA)
• contact adhesive
• UV hardening adhesive
• solvent cement
• epoxy resin

Question 2

What is polyvinyl acetate (PVA)?

Answer 2

• water based adhesive
• used to bond most woods and wood based materials together
• not usually waterproof adhesive
• can be used to bond wood joints together for furniture and other wooden products

Question 3

What is contact adhesive?

Answer 3

• used for bonding large areas such as sheet material
• can be used to join the same or different materials together, such as wood sheet to wood sheet, metal sheet to wood sheet, metal sheet to polymer sheet, etc
• the two surfaces to be joined are coated in contact adhesive and left for 10 mins, or until the adhesive feels ‘tacky’
• on contact with the other surface, adhesion is instant

Question 4

What is UV hardening adhesive?

Answer 4

• clear liquid
• quickly cures to for a bond when exposed to UV light
• contains a photo initiator, so as it absorbs UV light, it begins to cure and set to a solid bond
• can be used to join metal, glass and polymers
• excess adhesive can be wiped away with a cloth prior to being exposed to UV light
• gives a solid, clean joint

Question 5

What is solvent cement?

Answer 5

• most commonly a clear liquid called dichloromethane
• used to join polymers such as acrylic, ABS and PVC
• softens the surface of the polymers to be joined, allowing them to fuse together
• can be used in plumbing industry to bond non-pressure pipes made from ABS or PVC together

Question 6

What is epoxy resin?

Answer 6

• comes in two parts, resin and hardener
• used to join different materials together, e.g. timber to metal, metal to polymer, etc
• equal amounts of resin and hardener are mixed to form adhesive, which then takes time to fully set

Question 7

What are jigs and fixtures?

Answer 7

• often used to ensure that parts or components can be made repeatedly, more quickly and accurately
• a jig both holds the work and guides a tool, eliminating the need to repeatedly mark out
• a fixture is something that holds work in a given position while a manufacturing process takes place