Joining techniques Flashcards
1
Q
joining techniques
A
- PVA
- Tensol cement
- Liquid Poly Cement
- Contact adhesives
- Epoxy resin
2
Q
PVA
A
- join on edge grain
- if properly glued can be as strong as a single piece of wood
- won’t work on end grain
3
Q
Tensol cement
A
- joins plastics (eg acrylic) together permanently
- glued surfaces should be clamped together for 24hrs
- gives a permanent joint
- leaves strings, cant clean excess off
4
Q
Liquid Poly Cement
A
- plastic weld
- more appropriate for plastic
- works by capillary action
- 2 surfaces together put liquid along the joint
- cleaner and easier to use
5
Q
Contact adhesive
A
- to join plastics
- adhesive applied to both surfaces they are pushed together when glue appears to be dry
- used for large surface areas
6
Q
Epoxy resin
A
- many adhesives are plastics themselves
- Araldite hardens when a second chemical is added (catalyst)
- can bond most materials
- messy and smelly
- mix two parts for 1 minute
7
Q
wood joints
A
can be designed to hold without the use of glue or fasteners
8
Q
types of wood joints
A
mitred half lap
mortise and tenon
dove tail
lap joint
bridal joint
rebate
finger joint
dowel joint
9
Q
compare a dowel joint to a mortise and tenon
A
compared to a mortise and tenon, a dowel joint is a poor joint. Much of the surface of the dowel joint is end grain, which glue adheres to poorly. In a mortise and tenon joint most of the surface of the joint is longitudinal grain.
10
Q
mechanical joining
A
- temporary/ semi permanent
- various mechanical fasteners used, eg nails and screws
- nuts and bolts
- pop rivets
11
Q
A
12
Q
thermal joining
A
heat is used to cause a joint in a variety of ways: soldering, brazing, welding
13
Q
soldering
A
- a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint.
- filler metal has a relatively low melting point.
- heat is applied to the parts being joined, solder melts and is dawn into the joint by capillary action.
- soft soldering (PCB), hard soldering (jewellery), silver soldering (decoration)
14
Q
brazing
A
- filler metal/alloy is heated to melting temp
- quick doesn’t need much heat
- widely used in the tool industry to fasten hard metal (carbide, ceramics, cement and similar) tip s to tools such as saw blades.
- can be used for tacking prior to welding
- non ferrous on ferrous
15
Q
MIG welding
A
- metal inert gas
- a form of arc welding (electricity)
- used for general welding, mild steel
- as well as welding this can be used for cutting plate metal
