Most materials will require an exterior
finish to improve the look of the material and
to protect it from the environment. Surface finishes
can be applied by numerous methods including brushing,
spraying and dipping. The main surface finishes
that are available include paints, varnishes and
lacquers, oils, polishes, stains, sanding sealer,
plastic dip coating, powder coating, anodising,
plating, galvanising, enamelling, polishing and
Finishes are usually applied
for one or more of the following reasons:
1.) To protect the material from moisture, wear,
abrasion, fungus, mould or insect attack.
2.) To change the materials appearance, its colour
3.) To enhance the materials durability, surface
hardness or other properties.
Read the surface finishes overview
table below to learn more:
|Type of finish
Paints: are usually
suitable for metals or timber but not plastics.
Paints are divided into three main groups
oil based paints, water based paints and
solvent based paints.
|Car bodies, lawn mowers,
|Varnishes and lacquers:
are available in oil, water and solvent based
types. They are used on woods (*) however
some special types exist for metals.
External wood- boats/yachts,
Internal furniture, etc.
Oil: Various types
exist for metals or woods. Oil provides
an improved appearance for wood by enhancing
the grain. Vegetable oil can also be applied
to wood which comes in contact with foods.
Oil is also used on metals to protect it
|Wooden spatulas, salad
servers, Guns, engineering products.
French polish: is applied
to wood by using a brush and cloth to add
several layers which provides a deep finish.
Wax is then applied to improve the shine.
|Internal furniture only.
are used to improve the colour
of the wood. Wood stain if used on its own
only colours the wood and so and requires
a coating of wax or varnish to make it weather
|Benches, sheds, fences,
Sanding sealer: is
like varnish which is used to seal wood
to moisture. Sanding sealer is good as a
first coat before applying varnish or wax.
|Internal furniture only.
Plastic powder is used for dip coating.
The metal is heated and is then dipped in
a plastic powder eg: coat hooks.
|Tool handles. Garden equipment,
Powder coating: like
dip coating but it is a more sophisticated
process used in industry. The powder is
sprayed onto products which run through
|Metal desk frames, chairs,
internal car parts
Anodising: is a process
used on aluminium to provide a hard-wearing
corrosion-resistant finish. Anodising involves
electrolysis and uses acids and electric
|Used on aluminium products.
Plating: is another
process used on aluminium which uses electrolysis.
A thin plating layer of metal on the surface
provides a durable finish to metals which
are prone to corrosion.
|Bike wheels, kitchen equipment,
car parts, nuts/bolts/hinges where appearance
dipping metal into a bath of molten zinc.
The zinc provides a good corrosion resistant
|Gates, buckets, nuts and
bolts, screws, hinges, nails.
Many plastic products are self finished
for example injected moulded products. This
means the product does not need a finish.
|Injection mouled products.
Enamel: A powdered
glass is melted and fused onto the metal.
This requires high temperatures. This finish
is very heat resistant.
|Jewellery, baths, pots
and pans, oven liners.
Polishing: By hand
or with machines to produce a shine. This
is not a durable finish and the metal may
tarnish or oxidise again in the future.
Chemical polishes such a 'Brasso' use a
liquid borne abrasive to raise a shine.
|Jewellery, brass, copper
and bronze ornaments. Lacquer can be applied
to prevent oxidisation.
Mr DT says 'Read the text above and then answer
these questions below'. Write your answers
on a sheet of paper, dont forget to write
your name on the sheet!:-
1). Why are finishes usually applied?
2.) Name three metal finishes?
3.) Name three wood finishes?
4.) Name two plastic finishes?
5.) Name some products that wood stains are
6.) Name some products that enamelling is
7.) What is plastic dip-coating?
8.) How is french polish applied to furniture?
9.) What else should you use with sanding
10.) What oil should you use on wood which
comes in contact with foods?