Metal finishes

Question 1

Cellulose and acrylic paints

Answer 1

provide colour texture and protection against corrosion. Primarily used on low cost metal such as steel. Surface of metal needs to be cleaned and degreased prior to application. Can be applied using or brush or spray gun.

Question 2

Electroplating

Answer 2

Using a metal to coat another metal increasing it ability to withstand corrosion as well as increasing its aesthetics. The donor metal displaced in electrolyte solution. As a direct current Is applied the product attracts the donor metal and the product is electroplated.

Question 3

Dip coating

Answer 3

Metal coated by another metal by dipping the product in a tank of molten metal. Often used on low carbon steels. Commonly used with zinc and tin.

Question 4

Polymer dip coating

Answer 4

Metal product is heated. The metal component is then dipped into a tank of polymer powder which has air blowing through it. The air allows for a even coating across the metal and the heat melts the polymer onto the metal.

Question 5

powder coating

Answer 5

The product is negatively charged. Thermost polder resin which is positively charge is the sprayed through an airgun not the metal product and the positive and negative charged components attract each other. the product is then baked melting the polymer leaving an even coating.

Question 6

Varnishing

Answer 6

Provides a clear finish to the metal whilst still allowing the aesthetics of the metal to be seen. Commonly used for copper and brass. The varnish can be applied using a brush or an airgun spray.

Question 7

Sealants

Answer 7

Tough polymer based sealants protect polished surfaces from decay and tarnishing. Silicone clear sealants are often used in the automobile industry to protect metals against weathering road salts and insect attack. Applied with a cloth to machine mad the air dries in 15 minutes.

Question 8

Preservatives

Answer 8

They are generally used on moulds and dies to orient fingerprints showing on surfaces. They can be applied by wiping with a cloth, spray on immersion.

Question 9

Anodising

Answer 9

Commonly used for aluminium products which enhances the natural oxide layer resulting in the aluminium having increased hardness and toughness. It can also provide colour. Similar process to electroplating. An electric current passes through sulphuric acid from the part to be treated to a negative cathode. As the current passes from the part to be treated to the negative cathode, the aluminium oxide layer builds up producing the anodised layer.