Polishing Aluminium

polishing aluminium

Polishing Aluminium – Our guide 

Here at Moleroda, we have been assisting polishers and toolrooms on the best way to polish aluminium for the last 40 years. So here is our definitive guide to polishing aluminium.

This guide will focus on polishing aluminium using a bench polisher, but if you want to get more precision you can of course use a micromotor. 

polishing aluminium

What is aluminium?

Aluminium is a silver metal. It’s the most widespread metal on Earth, making up more than 8% of the Earth’s core mass. Aluminium has good electrical and thermal conductivity, high reflectivity, and resistance to oxidation.

aluminium metal

Aluminium in Engineering

Smelting aluminum was first developed, allowing for its large-scale production, this element has become an increasing part of our everyday lives, whether we are aware of it or not.

From aviation to automobiles, to digital technology, aluminum alloys have allowed for faster production processes using cheaper and more flexible materials. Main engineering industries that use aluminium are:

  • Mechanical engineering
  • Automated equipment and robots, use aluminum for its light weight and formability.
  • Mould tool for its ability to be turned into all sorts of shapes
  • Structural engineering- for buildings etc
  • Electrical engineers also rely on aluminum alloys for many applications. 

The benefits of using aluminium

  • Its lightweight
  • Its extremely strong
  • Aluminium has outstanding strength-to-weight ratio
  • It has extreme corrosion resistance.
  • Aluminum structures and equipment have a longer lifespan and require less maintenance than many competing materials.
  • high conductivity, both in terms of electrical and thermal
  • Aluminum is easy to work with and can be made into nearly every conceivable shape.

Polishing Aluminium – the challenges

People think that aluminium is easy to polish as its softer than stainless steel, but actually its harder because it is easy to get pick up or fishtails. This is where soft pieces are pulled out and you can get lines and marks in the aluminium. It is therefore so important to crosshatch in aluminium to eliminate lines and marks put in by first and second stages of polishing. 

The main issues can be:

  • The wrong type of abrasive being used
  • Not crosshatching before polishing
  • The wrong RPM is used to achieve the surface finish and this creates too much heat
  • Pitting can be created when you pull out hard bits from the underlying surface, this is called drag.  
  • Too much surface distortion and holes in the parts
  • Too much downward pressure from polishing
  • Using too long a stroke.

Mounted felt for polishing

Polishing Aluminium on a bench grinder

Did you know that you aswell as polishing larger items with our selection of wheels and mops on your bench grinder – you can turn it into a polisher using our pigtails with an end hole? Check out our selection of banch grinders and pigtails to make sure you have the right equipment to get you started.

Mandrels, Pigtails & Tapers

Bench Grinder Tapers/Pigtails

£12.00£21.14 incl VAT

Bench Polishers & Grinders

Bench Polisher DSM 200 900w 230v

£456.00 incl VAT

Stage 1. Getting the aluminium ready  – pre -polishing

This stage is crucial for creating those cross hatches. This will help you eliminate lines and marks put in through first and second stages of polishing. 

For this you need to use dry sisals and apollo compound.

£5.38£13.88 incl VAT
£2.94£29.40 incl VAT

Mounted Calico, Cotton Yarn, Chamois Mops

Mounted Mini Mops for metal polishing

£17.27£25.13 incl VAT

Stage 2 – mid stage polishing 

We recommend using 200D for polishing alloy. 2000D is suitable for all metals including aluminium, brass, steel, silver etc. It is a very good – green – one operation bar and produces a nice finish.

Mounted Calico, Cotton Yarn, Chamois Mops

Mounted Mini Mops for metal polishing

£17.27£25.13 incl VAT

3rd stage – Final Finish 

For the final finish when polishing aluminium we recommend using either FF9 or P175 Menzerna. FF9 is out most popular finishing compound and will give you a great shine and finish. Alternatively, P175 is the finest compound, excellent on softer metals such as precious metals such as gold and silver and aluminium it is much cleaner to use and gives a better finish in less time.

£8.41£46.20 incl VAT
£3.97£79.22 incl VAT

Ask the experts

If what you have seen here doesn’t quite answer your questions in relation to polishing aluminium then why not take a look at our You Tube Channel or give us a call!