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A-level Product Design > Surface Finishes > Flashcards

Surface Finishes Flashcards

1
Q

Galvanising

A

Galvanization is the process of applying a protective zinc coating to steel or iron in order to prevent premature rust and corrosion.

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2
Q

Galvanising advantages (4)

A

Less maintenance/Lowest long term cost.
Long life expectancy.
Outstanding resistance to mechanical damage.
No lost time in surface preparation, painting and inspection.

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3
Q

Galvanising disadvantages (2)

A

Other methods which may be more effective in different circumstances
Costs

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4
Q

Galvanising Uses (3)

A

Galvanised steel is available in a variety of forms, such as galvanised pipes and galvanised wire.
Galvanised steel frames are used to build houses.
Car parts are made out of this type of steel (for example, the body parts of trucks and buses).

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5
Q

When to use galvanising

A

• construct or repair steel structures, for example, benefit from lower maintenance and repair costs because of its special properties.

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6
Q

Galvanising process

A

The true galvanising phase of the process consists of completely immersing the steel in a minimum 98% pure zinc bath. The bath temperature is maintained at 815 F (435 C) or higher. The steel is lowered at an angle by crane hoist. This allows air to escape from tubular shapes or pockets that may be within the design of a fabricated piece and of course permits the molten zinc to displace the air.

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7
Q

Powder coating

A

cover (an object) with a polyester or epoxy powder, which is then heated to fuse into a protective layer.

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8
Q

Powder coating stage 1

A

Ensure all rust/corrosion is removed from the part, then degrease, note use a lint free cloth as the fibres can adhere to the part and leave imperfections on the cured part. Allow the part to dry fully prior to applying powder. At this point mask off any threads or areas not requiring covering with powder.

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9
Q

Powder coating stage 2

A

Hang the part on a hook and attach the earth clamp in a discrete area. Note without a good earth to the part you will never get good coverage or efficient use of powder.

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10
Q

Powder coating stage 3

A

Screw the flow screw to closed position (clockwise) then while aiming the gun tip away from the part pull the gun trigger fully, gradually unscrew the flow screw so the powder exits the tip of the gun as a gentle cloud, eventually experience will determine the size of the cloud.

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11
Q

Powder coating stage 4

A

Aim the gun at the part to be coated approx 200mm away, depress the pedal and keep it depressed (green light comes on) then apply the powder by pressing the gun trigger, ensure all of the part is fully coated. Note coat all internal corners first as it will be harder to get full coverage if left till last.

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12
Q

Powder coating stage 5

A

Unclip the earth lead and without depressing the pedal, spray the powder over the area where the earth clamp was positioned to provide full coverage

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13
Q

Powder coating stage 6

A

Finally inspect the part for imperfections and full coverage, then transfer the coated part on the hook to the oven (or other heat source) taking care not to rub the powder off.

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14
Q

Powder coating stage 7

A

Cure the part by achieving a surface temperature of 180 deg c then letting it cure for a further 10 minutes (for some powders this will vary up to 200 deg c for 15 min’s) As a tip, the surface of the part will be at the correct temp when it fully glosses over.

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15
Q

Powder coating stage 8

A

When the part has fully cured in the oven let it cool down and it is then ready for use. Note if you have any masked areas remove the tape when still warm as it is much easier

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16
Q

Powder coating advantages (4)

A

Long lasting, durable finish
Large range of colour options
Cheap
Environmental friendly

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17
Q

Powder coating disadvantages (3)

A

High start up costs
Little control over smoothness
Hard to get thin coating- layers

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18
Q

Powder coating uses (4)

A

Appliances e.g. dishwasher, air conditioner,
Cars/car parts
Buildings e.g. posts, fencing
Everyday products

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19
Q

Anodising advantages (5)

A

It’s a very thin coating compared to paints and powders.
Extremely durable, hard, abrasion resistant and long lasting. The coating does not peel or chip. Much harder surface than paint and powders.
Lasts indefinitely.
Environmentally friendly finish. Can easily be recycled.
Inexpensive compared to painting and powder coating.

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20
Q

Anodising

A

Anodising is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminum is ideally suited to anodising, although other nonferrous metals, such as magnesium and titanium, also can be anodized.

21
Q

Anodising disadvantages (2)

A

Limited color selection.
Touch-up of anodized product that is severely damaged in your shop or the field is more noticeable than air dry touch up paint for painted products.

22
Q

Anodising stage 1

A

The metal part to be treated (generally aluminum) is first submerged in an electrolytic solution bath along with a cathode.

23
Q

Anodising stage 2

A

When a current is passed through the acid solution hydrogen is released from the cathode and oxygen forms on the surface of an anode. This results in a metal oxide film growing on the surface of the part being treated.

24
Q

Varnish

A

resin dissolved in a liquid for applying on wood, metal, or other materials to form a hard, clear, shiny surface when dry.

25
Q

Varnish application

A

Varnish can be applied in any of three ways: by brush, with a roller and pad, or by spraying. Brushing is a time-tested technique and many high-quality brushes are available.

26
Q

Varnish advantages (3)

A

Resistance to heat, wear, solvents, acids, and alkalis
Resistant to water
Easy to apply

27
Q

Varnish disadvantages

A

Slow Cure times – Varnish takes a long time to dry which is why it is easy to brush on as you have a lot of time to work with. However, the long dry time allows for greater potential for dust to settle on your finish
Not sprayed easily

28
Q

Lacquer

A

a liquid made of shellac dissolved in alcohol, or of synthetic substances, that dries to form a hard protective coating for wood, metal, etc.

29
Q

Lacquer advantages (3)

A

Quick drying time
Relatively Low Cost
Variety of appearance

30
Q

Lacquer disadvantages (4)

A

Has high VOC content which is harmful to the environment
Less resistant to heat, solvent, acid, and alkali when compared to varnish
Limited scratch resistance
Low solid content results in poor film building properties

31
Q

Varnish uses

A

Varnishis primarily used in wood finishing applications where the natural tones and grains in the wood are intended to be visible. It is applied over wood stains as a final step to achieve a film for gloss and protection.

32
Q

Lacquer Application

A

Lacquer is available for application with either a brush or as a spray. However, it is not a good idea to try and brush on a spray-on lacquer application, as the spray versions are much quicker drying.

33
Q

Lacquer Uses

A

The term lacquer is used for a number of hard and potentially shiny finishes applied to materials such as wood. … In modern techniques, lacquer means a range of clear or coloured wood finishes that dry by solvent evaporation or a curing process that produces a hard, durable finish.

34
Q

Oil Uses

A

lastic-like coating that gives a hard wearing, protective finish or seal to floors and other wooden surfaces.

35
Q

Wood Oils

A

Oil is one of the most popular ways to finish wood. The protection delivered by oils isn’t quite as robust and effective as contemporary wood finishing products like varnishes. But on the plus side, oils tend to bring out the character of the wood better, they’re made of natural products, plus they’re very easy to apply and maintain.

36
Q

Wood Oils Applications

A

Oilis a natural product.Oilscure slowly and penetrate into the surface of thewood. Multiple coatings can be applied until thewoodis unable to absorb any more. Additional coats can be applied if desired to create a surface build or coating ofoil.

37
Q

Wood Oils Advantages (3)

A

Penetrates the wood, repairing more than just the surface
Dries solid, filling cracks and defects
Restores the original color of the wood

38
Q

Wood Oils Disadvantages (3)

A

The floor will still be vulnerable to water damage
Lacks the smooth and glossy appearance of a varnish or lacquer
Should be reapplied every 6 months or so

39
Q

Polyurethane

A

a synthetic resin in which the polymer units are linked by urethane groups, used chiefly as constituents of paints, varnishes, adhesives, and foams.

40
Q

Polyurethane advantages (2)

A

One of the most durable coatings – Polyurethanes within the varnish category are one of the most resistant to scratching , heat, alkyd, acids, and wear
Beautiful appearance – Polyurethanes create one of the most attractive protective finishes after application

41
Q

Polyurethane Disadvantages (2)

A

Long dry time – a typical polyurethane can take up to 24 hours to dry
In between coats requires sanding – typically polyurethanes will require sanding between coats as it will not bond without proper

42
Q

Polyurethane uses

A

It is so flexible that it is often used in products that are designed for human comfort and relaxation. At the same time, it is so durable that it can be used in tires for heavy machinery. It is also a “green” material, as it often helps cut emissions through its insulating potential.

43
Q

Shellac

A

ac resin melted into thin flakes, used for making varnish.

44
Q

Shellac Advantages

A

Provides an excellent barrier for water vapor, silicone contamination, and existing stains which means it is sometimes used as a sealer coat
Is one of the best touchup finishes for repairing dings and scratches in any wood finish
Uses mild solvents making it less harmful to the environment

45
Q

Shellac Disadvantages

A

Weak protection against heat, water, solvents, and chemicals – this makes it less than ideal for tabletops or high use furniture pieces
Weak resistance to wear
Short shelf life

46
Q

Wax

A

Basic wood finishing procedure. … Once the wood surface is prepared and stained, the finish is applied. It usually consists of several coats of wax, shellac, drying oil, lacquer, varnish, or paint, and each coat is typically followed by sanding.

47
Q

Wax application

A

Apply the wax sparingly with a cloth on delicate surfaces.

48
Q

Wax Advantages

A

Wax finishes provide a very glossy surface and can be easily removed too.

49
Q

Wax Disadvantages

A

They are not very durable and one has to apply them frequently.

A-level Product Design (24 decks)

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