3.4 joining techniques Flashcards
types of adhesives:
a
contact adhesive
rubber-based and can be made from natural or synthetic rubbers. Once the adhesive is touch dry the two surfaces are then secured with some pressure and
the bond is immediate.
acrylic cement
Dichloromethane works by dissolving the surface of hard plastics. Generally, it is used for edge glueing.
epoxy resin
The Epoxy resin sets when equal amounts of resin and hardener are mixed together. It then chemically sets to form a very hard material.
PVA (Polyvinyl acetate)
PVA works when it soaks into the surface of the wood and sets once all the water is absorbed.
Hot melt glue
Works by heating a stick of glue which resets when cool forming the bond. The glue is a kind of thermoplastic.
Cyanoacrylate
(superglue)
They provide instant bonding, clear bond lines, and cures in seconds.
PS cement
The product works by melting the plastic on application and ‘welding’ two glued pieces of plastic together
contact adhesive
materials
advantages
disadvantages
a
All Veneers, Plastic, laminates adv Adhesion takes place as soon as the two surfaces are placed together. No clamping required Multi-material.
disadvantages There is no opportunity to reposition the pieces. Relatively expensive Contains VOCs
acrylic cement
materials
advantages
disadvantages
a
Acrylic
HIPS
ad
Rapid bonding of
acrylics
disadvantages Difficult to apply Difficult to give a neat joint Relatively expensive Contains VOCs
epoxy resin
materials
advantages
disadvantages
a
all
ad High strength bonds Versatile Excellent chemical and heat resistance
disadvantages Expensive Reaches full strength only after a few days Requires manual mixing of two elements (resin and hardener) Can be messy
PVA (Polyvinyl acetate)
materials
advantages
disadvantages
a
Wood
Fabric
Styrofoam
ad Gives a strong joint Relatively inexpensive Water-based
disadvantages Surfaces need to be securely clamped together for a long period of time (24 hours) Generally not waterproof
hot melt glue
materials
advantages
disadvantages
a
Model making Any materials
ad Range of colours Good bond for models Quick to harden
disadvantages Not great for final models Safety issues with hot glue
Cyanoacrylate
(superglue)
materials
advantages
disadvantages
a
Industrial Medical Home use All materials
ad
Stong
Fast-acting
disadvantages
Short shelf life
Skin contact
ps cement
materials
advantages
disadvantages
a
Model kits HIPS ABS
ad
Strong bond
Can use a brush to
apply
disadvantages
Relatively
expensive
Contains VOCs
mechanical joining methods
b
screws
Screws are often one part of a temporary joint.
nuts and bolts
Nuts and bolts are usually manufactured from low or medium carbon steel.
rivets
Riveting is a method of making a permanent joint in metal.
screws
machine screws
b
Machine screws have parallel sides with
standard threads cut into them. They are usually
made from carbon steel and are mass-produced. They come with a variety of heads,
the most common being countersunk and
cheese heads.
screws
wood screws
b
Wood screws are classified firstly by the shape of
the screw head and secondly by the length of the
screw itself. They come with three different types of
head, countersunk, raised and rounded.
nuts and bolts
nuts
b
Specialist nuts are used for particular situations.
The advantage of using nuts and bolts is that they can be easily undone, allowing for components to be replaced or repaired.
nuts and bolts
bolts
b
The most commonly used thread form is the ISO metric
thread. The other measurement that is often
quoted when discussing threads is the pitch. The
pitch of the thread is the distance that a screw or
bolt with travel through one revolution.
rivets
solid rivets
b
Solid rivets are manufactured from soft iron
because they need to be ductile and easy to
work as they have to be hammered into shape.
rivets
pop rivets
b
Pop rivets are usually manufactured from
aluminium and instead of being hammered into
shape, they are fixed into place using a pop rivet
gun.
