3.4 Joining Flashcards
Adhesives
Used to join/stick different materials together
What is contact adhesive used for?
Used for bonding large areas such as sheet materials together.
Can join the same or different materials together.
How is contact adhesive used?
The two surfaces to be joined are coated in contact adhesive and left for a few minutes until the adhesive feels tacky.
On contact with the other surface, adhesion is instant
What is acrylic cement?
A clear liquid to join polymers such as acrylic together.
How does acrylic cement work?
Acrylic cement softens the surface of the polymers to be joined allowing them to fuse together.
What is epoxy resin?
A two part adhesive (resin and hardener).
How is epoxy resin used?
The two parts are mixed together in equal parts. Used to join different materials together.
What is PVA (polyvinyl acetate)
A white liquid water based adhesive, which is not usually water proof.
How is PVA used?
Used to join woods and wood composite materials together.
What is hot melt glue?
A cylindrical solid stick of adhesive which is melted in a hot glue gun and applied. Not a structurally strong adhesive.
How is hot melt glue used?
Applied using a glue gun, which has a heating element to melt the glue stick.
Used to join different materials.
What is superglue (cyanoacrylate)
A fast setting clear liquid which works best in the presence of slight moisture.
How is superglue used?
Reacts with the moisture to create a very tight and instant bond.
Used to join different materials together.
What is polystyrene cement?
A clear gel consistency liquid used to join rigid polystyrene polymers together.
How is polystyrene cement used?
Polystyrene cement softens the surface of the polymers to be joined, allowing them to fuse together when the cement hardens.
Adhesion is not instant on contact, allowing parts to be positioned before the adhesive dries.
Mechanical joining
Mechanical joining uses parts to create a join which may be used to ease production assembly.
Uses of screws
Joining wood to wood, metal to wood or wood to sheet polymer.
How screws are used?
A clearance hole is drilled in the top part to be joined and a pilot hole is drilled into the bottom part to be joined. this aids the screw to bite into the material to create the join.
Uses of nuts, bolts and washers?
Joins materials for disassembly or to allow access for repair.
How are nuts, bolts and washers used?
The bolt sits in a clearance hole drilled through both parts to be joined.
The bolt usually has a washer and then a nut on the threaded end to be tightened and create the join.
Washers spread the load applied by the nut and prevent material damage from the nut being tightened.
Uses of rivets?
Rivets are generally used to join thin sheet metal together.
How are rivets used?
Riveting uses two pieces which are overlapped and drilled, then hammered over to join.
Uses of pop rivets?
Pop rivets join thin sheet metal but are very useful for where the underside of the joint is inaccessible.
How are pop rivets used?
Pop riveting uses a rivet gun and a rivet and pin.
Uses of press joining?
Joins thin ductile sheet metals together, more often used for bulk sheet metal applications.
How is press joining used?
Material to be joined is placed in a machine and pressed between a punch and die.
Under pressure the metal deforms into an interlocked shape.
Press joining is not as strong as riveting.
Heat joining
Used for permanently joining metals.
Oxy-acetylene welding
Uses a steel filler rod to create the weld.
Useful for repair jobs or where there is no electrical supply.
MIG welding
Uses an electrode wire with an inert gas such as carbon dioxide or argon.
Suitable for thin gauge metals.
Brazing (Hard soldering)
Uses a brass filler rod using either oxy-acetylene or a gas/compressed air brazing hearth.
Suited for one off production or small batch.
Joins dissimilar metals.
Soft soldering
Generally joins copper or brass for light use applications.
Uses a filler rod to flow between the metal surfaces to create the join.
Carried out using a soldering iron or gas torch.
Jointing
Traditional wood joints used in manufacture.
What is a comb joint used for?
Box conduction, decorative edge joining
What is a housing joint used for?
Framework construction, cabinets and shelving
What is a half lap joint used for?
Simple frames, boxes
What is a dowel joint used for?
Lightweight shelving or corner joining.
What is a mortise and tenon joint used for?
Frame construction
Knock down fittings
Allow products to be assembled and disassembled numerous times without weakening the joint.
Often used in flat pack furniture.
Types of knock down fittings
- corner blocks
- CAM lock fittings
- barrel and screw
- cabinet hinges
