It's a question we get asked time and time again: 'What is the best finish for my steel project?'
Ensuring the correct finish of a steel project is just as important as the production process. When determining the best finish, you should take into account whether the finish is applied purely for aesthetic reasons or for additional corrosion protection. If the proper finish is not applied, chances are the product will not survive the test of time and you will soon notice signs of deterioration!
A high-quality finish provides the 'wow' factor and if your product is used as a display object, such as a staircase designed to impress, you can choose from a wealth of aesthetic finish options.
As experts in steel (and a responsible company that wants our customers to be nothing less than satisfied!) we can provide excellent advice on how to achieve the look and feel you want while ensuring the product is well protected against the elements.
In this blog we take you through some common metal finishing products and methods that can be used to provide a high-quality finish and ensure your product lasts a lifetime...
Preparation is essential: grit blasting
First of all: preparation! To obtain a good finish it is necessary to remove all mill finishes and coatings common to large steel profiles. Removing imperfections provides a good base (also called 'etching') to which the paint or coating can adhere.
Shot blasting is the process of applying abrasive particles under high pressure to remove impurities. A rapidly rotating throwing wheel, housed in a special steel structure that guides the metal, is used to blow abrasive particles onto metal profiles. Shot blasting is also used to remove rust and old paint.
Powder Coating: A consistent, high-quality finish
Powder coating is a dry finishing process that has become very popular in recent decades. Powder coating can be applied to a wide range of products and provides a uniform, high-quality finish. It can be applied to large areas in a short time, making it an effective option for large-scale projects. Powder coating is used not only for its functional and durable properties, but also for its decorative and attractive finish, which is available in a wide range of color options.
Now for the science part... powder coatings are based on polymer resin systems, combined with hardeners, pigments and other additives. These ingredients are mixed in the melt and, after cooling, ground into a uniform powder. A process called electrostatic spray deposition (ESD) is generally used to apply the powder coating. This uses a spray gun that gives the powder particles an electrostatic charge to attract them to metal. After application, the parts are cured in an oven and the coating reacts chemically to produce long molecular chains that are highly resistant to degradation.
Still with us? The result of this process is a highly durable, uniform coating that protects metal in outdoor environments exposed to the elements. Due to the application method, powder coating is a cost-effective way to treat aluminum, mild steel and stainless steel. You often see powder coating on items such as railings, fence panels and gates.
Galvanizing: withstand the test of time!
Galvanizing is an industrial finish applied to mild steel or carbon steel to provide a protective coating. A zinc layer is applied through a thermal process to coat the metal and prevent rust and corrosion. Electroplating is an extremely versatile process and an easy way to provide corrosion protection to building materials exposed to atmospheric conditions. Electroplating can be applied to large areas of metal, but is also cost-effective for use on smaller items, making it a very versatile option. Once galvanized, the steel requires no further maintenance and will stand the test of time!
'Warm to the touch': extra comfort and luxury
Similar to the powder coating process, 'Warm to Touch' is a plastic coating that is applied via a spray system and is applied, for example, to handrails to provide extra comfort. The high-quality PVC coating prevents heat conduction from the hand. The material is available in a range of colors and is UV stable and weather resistant, making it ideal for external or internal requirements and industrial or commercial environments. The end result is extremely durable and provides an even, uniform finish without dirt. With many combinations of colors and textures available, this product range allows designers to find the finish that suits their individual development.
Stainless steel
Stainless steel is an alloy of iron with at least 10.5% chromium. Chromium produces a thin layer of oxide on the surface of the steel, known as"passive law", which prevents surface corrosion. An increased amount of chromium provides increased resistance to corrosion.
There are many different types of surface finishes on stainless steel, some of which are applied later during processing. Finishes include polished, brushed, blown, etched and colored finishes. Choosing the correct surface finish is important in determining the corrosion resistance of the stainless steel surface. A rough surface finish can reduce corrosion resistance. View the different finishes recommended by the British Stainless Steel Associationher.
Stainless steel can provide an impressive 'wow' factor and can be used to complement various architectural features. It is also incredibly durable and requires no additional maintenance after installation.
Natlak (epoxycoating)
Wet paint systems, also called 2 Pack Paint or EpoxyPaint, are paint systems that contain an acrylic paint, melamine (the color) and a hardener resin. When combined, these two resins result in a chemical reaction that produces a hardened solution.
Epoxy paint systems are a top choice for many industrial coating applications, including steel, metal and concrete. The system is applied by spray, making it more suitable and effective for larger, less complicated applications.
Epoxy coatings offer optimal protection against wear, corrosive liquids and extreme temperatures and are also resistant to many corrosive substances. When epoxy cures, it becomes a hard, finished surface that will last for many years, even under exposed conditions.
Zinc low
Galvanizing is the process of electrolytic deposition of zinc on mild steel or iron parts. Galvanizing acts as a sacrificial layer and will slowly corrode over time, protecting the underlying steel. The other major benefit of galvanizing is that the coating itself improves the appearance of the base metal; clear galvanizing has an attractive bright silver/blue appearance.
To achieve the best results when galvanizing, the condition of the material is of great importance. Pure rust/limescale-free metal gives the best finish.
The zinc layer is passivated for better corrosion resistance. Depending on the application and whether the product is exposed to the elements, different types of passivation are available. Clear (blue) passivate is often used for machine parts and washers, screws, fasteners and the finished appearance is bright glossy silver/blue. Yellow passivate provides better corrosion resistance and is therefore often used for engine parts and general outdoor parts. Black Passivate (TrivalentChromium) offers excellent corrosion resistance and is mainly used for decorative purposes where a dark finish is required.
Galvanizing is suitable for smaller, complicated applications that may have moving parts such as hinges or door locks.
For more information about which finish is right for your project, contact our team!
Call 0151 637 3600 or email sales@clmltd.co.uk.
