Design - Joining Techniques

Question 1

what is the difference between a temporary joint and a permanent joint?

Answer 1

Temporary joints can be removed easily (such as a screw, nuts and bolts and knock down joints)
Permanent joints cannot be removed without damage to the product (eg. glue, rivets, welding, wood joints)

Question 2

What types of wood joints are there?

Answer 2

Butt joint- weak joint but quick an easy
Lapp joint - stronger than butt joint due to higher surface area
Dowel (connected with wooden pegs)
Mortise and Gauge - Fits into cut hole
Finger/ dovetail joints - interlocking strong joints

Question 3

What is a pop-rivet?

Answer 3

The joining of two thin materials using a rivet gun.

Question 4

What are the 3 types of heating joints?

Answer 4

Soldering
Brazing
Welding

Question 5

What is soldering?

Answer 5

Melting alloy with higher melting point to join other materials
FLUX is often used before connecting to prevent oxidation

Question 6

What is brazing?

Answer 6

Similar to soldering however using higher temperatures

Question 7

What is welding?

Answer 7

Strongest heating joint where edges are melted to connect to each other
Any gaps are filed with filler

Question 8

What are 3 examples of adhesives?

Answer 8

PVA glue
Epoxy Resin
Liquid Solvent Cement

Question 9

What are the properties of PVA Glue?

Answer 9

• Not fully waterproof
• Flexible
• Does not emitt odours
• Joins Wood, vinyl or paper
• Takes 24hrs to fully dry
• Turns clear when dry

Question 10

What are the properties of EPOXY RESIN?

Answer 10

• Strong
• Low shrinkage
• Low cost and toxicity
• Works well for plastics , aluminium and glass
• 24 hrs to dry
• Very strong
• Requires the mix of two different parts to a 1:1 ratio to be activated

Question 11

What are the properties of liquid solvent cement?

Answer 11

• highly flammable
• Can be toxic if ingested
• Brush to apply
• Dries very quickly (2hrs)
• Good for sticking plastics together
• Strong bond