Polishing aluminium  

This is the experts guide to polishing aluminium. This is a detailed step by step guide to everything you need to know about polishing aluminium and getting the surface finish you require. 

Why work with aluminium? 

Aluminium is a versatile and widely used material in engineering due to its various properties and advantages. Furthermore, polishing aluminium leaves behind a beautiful and smooth surface.

Here are some common applications of aluminium in engineering:

Electrical Conduction: Aluminium is a good conductor of electricity, making it suitable for electrical transmission lines, overhead power cables, and electrical components like heat sinks and busbars.

Heat Transfer: Aluminium’s high thermal conductivity makes it ideal for heat transfer applications. It is commonly used in radiators, heat exchangers, and HVAC systems.

Aerospace: The aerospace industry relies heavily on aluminium due to its combination of strength, lightness, and resistance to corrosion. It is used in aircraft frames, wings, and other critical components.

Marine: Aluminium’s corrosion resistance makes it suitable for marine applications, such as boat hulls, masts, and other components.

Manufacturing Tools and Equipment: Aluminium is used to create tooling and equipment in manufacturing processes due to its ease of machining and low friction properties.

Automotive: Besides structural components, aluminium is used in engines, transmissions, and suspension systems to reduce weight and improve fuel efficiency.

Building and Construction: Aluminium is used in windows, doors, curtain walls, and roofing systems due to its lightweight, corrosion resistance, and design versatility.

Medical Devices: Aluminium is used in various medical devices and equipment due to its biocompatibility and resistance to corrosion.

Aluminium’s versatility, lightweight nature, corrosion resistance, and good mechanical properties make it a valuable material in a wide range of engineering applications, contributing to improved performance and efficiency in various industries.

How easy is it to achieve a mirror finish on aluminium? 

Aluminium can be polished to achieve a mirror-like finish, but the ease of achieving this finish depends on several factors, including the quality of the starting surface, the aluminium alloy, and the tools and techniques used. Here are some key considerations:

Initial Surface Condition: The starting condition of the aluminium surface is crucial. If the surface is relatively smooth and free of deep scratches or defects, achieving a mirror finish will be easier. Rough or damaged surfaces will require more effort and time.

Aluminium Alloy: Different aluminium alloys respond differently to polishing processes. Some alloys are easier to polish than others due to their inherent properties. Alloys with a higher aluminium content (e.g., 1000 series) often polish more easily than those with alloying elements (e.g., 2000 or 7000 series).

Tools and Techniques: Achieving a mirror finish typically requires using progressively finer abrasives or polishing compounds. The process may involve sanding, buffing, or using specialized polishing wheels or equipment. Proper techniques, such as maintaining consistent pressure and avoiding over-polishing in one area, are essential.

RA Value: The surface roughness (RA value) you want to achieve plays a role. Achieving an extremely low RA value (e.g., less than 0.1 µm) for a mirror finish can be more challenging and may require specialized tools and expertise.

Time and Patience: Achieving a mirror finish is a meticulous and time-consuming process. It often involves multiple steps, with progressively finer abrasives or compounds, and may require patience to achieve the desired result.

The steps to achieving a mirror finish on aluminium

These steps are for those using a bench grinder. However, the same steps can be used with mounted items and a dremel or micromotor.

Step 1: Preparing the surface

This first polishing cutting and flattening stage is very important therefore it shouldn’t be rushed. The subsequent polishing processes after this phase should be very quick and will only be as good as the pre-polish phase.

We recommend starting with a dry sisal. These mops can be used on all metal types. You need to use your sisal with a polishing compound such as Apollo. Alternatively, you could use a RODA NyMop with which you don’t need any compound. 

 

Step 2: Mid stage 

Pre-polishing preparation is very important or you will be polishing all the peeks on the surface and you will not achieve a good finish.

For this stage you need white stitched mops. These mops are made from soft layers of calico which have been stitched together to give rigidity. They are most the versatile mop and could be used as a one operation for a general polishing. This type of mop is useful on such a range of materials it is popular with most users. Use these with 2000D.

3rd Stage: Final finish polishing 

For this stage we recommend loosefold polishing mops. These mops are for final finishing metal to create a bright reflective mirror finish. You must make sure that the metal surface has been worked and flattened. Use this mop with either FF9 or Menzerna when polishing aluminium. 

 

In Conclusion

In summary, achieving a mirror finish on aluminum is possible, but it may require time, effort, and attention to detail, especially if you are working with a rough or highly reflective finish. The ease of achieving this finish will depend on many factors, so it’s essential to assess the starting condition of the aluminium and choose the appropriate tools and techniques for the job.

More Information 

For more information on polishing give us a call – we have experts here who have been polishing for years! 

And take a look at our You Tube page for videos of us hard at work finishing!