Finishes
Considerations for finishing metal fabrication
Finishes
There are many ways that metals can be finished, and these change drastically from material to material. Due to the enormous number of options and differences, students should engage in research to discover their needs. It is important to understand the desired finishing at the beginning of the design process, as some finishing will require pre-planning. Some of the finishes students may like to consider include.
Painting
Powder-coating
Hot Dip Galvanising
Polishing
Electroplating
Patina
Oiling (blackened)
Painting
The simplest finishing method to coat steel and other metals is to paint it. Aerosol paints will provide the best finish. It is important to begin with an etching primer which will give the best possible base for the paint to adhere.
Powder-coating
A cost effective and robust finish. Powder-coating is a processes of adhering and baking on fine pigment. It forms a strong protective layer and comes in a wide range of colours and effects making it popular in furniture and homewares.
Hot-dip Galvanising
In order to protect steel from oxidization, especially in outdoor applications, it can be galvanized. This is a processes whereby an object is dipped into a bath of molten zinc, forming a protective layer. Galvanised objects can then be painted or powder coated.
Galvanizing is a complex process and requires consideration from the beginning of the design.
Polishing
A popular finish with stainless steel, where it achieves the best results. Polishing can be obtained to different levels of refinement. The highest being a 'mirror' finish. Achieving these finishes is time consuming and requires special equipment. Simple polishing can be done relatively easily.
Polishing works for many non-ferrous materials, such as copper, brass, bronze however over time it will dull. It works best on hard materials, such as stainless steel, and is less effective on soft metals such as aluminium.
Electroplating
Where it is desired for metal object to have the appearance of another metal, electroplating is an efficient application for small parts. By using electrical charge in a special bath, microns of metal can be transferred onto the surface of an object, providing a comprehensive finish.
Patina
Patina is a process of using chemicals to affect a surface. Patina often happens naturally due to exposure to oxygen, for example, when copper roofs slowly become turquoise. This is a deposit of by-product on the surface of the material which can provide the desired effect.
Oiling
Oiling is essentially another form of patina, steel can be 'blackened' using linseed oil and heat to create an textured and matter surface finish.
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