Machine polishing is a crucial aspect of the car detailing process. It’s designed to remove scratches and swirl marks in a car’s clear coat layer of paint, and improve the depth of gloss and colour. In this guide, we’ll explain exactly what machine polishing is and why it’s so important.
Machine Polishing 101
In short, machine polishing is the process of removing clear coat defects (such as marring, scratches and swirl marks) in a car’s paint.
The technique involves using a machine polisher paired with a foam, microfibre or wool pad which spins at a high rate. The pad is primed with a polishing compound or liquid which produces light abrasion. This process removes a very thin layer of clear coat paint to reveal a fresh, glossy layer which is free from defects.
What are Swirl Marks & Paint Defects?
Before we dive into the specifics about the machine polishing process, we first need to address what paint defects actually are.
Paint defects can take a whole host of forms including deep scratches, stone chips, bird dropping and chemical etching, and clear coat scratches and swirl marks. Machine polishing primarily addresses clear coat scratches and swirls.
Modern vehicle’s have several layers of paint. From the bottom (sitting on the metal) to the top (exposed to the environment), here are the layers:
- Primer (typically grey)
- Base (the colour of the vehicle e.g. red, blue, white, silver, etc.)
- Clear (a transparent protective layer)
The clear coat layer of paint can be easily scratched by anything from poor wash technique (e.g. using brushes or automatic car washes) to hedge rash (common on cars driven down tight country roads).
Clear coat scratches and swirl marks cause the paintwork to look dull and lose its lustre/ depth of colour. They are also easily visible under direct light, often taking on the appearance of spider webbing.
Polishing process Explained
In order to address the clear coat defects described above, the damaged layer of clear coat paint needs to be removed. This is where machine polishing comes in.
It’s a controlled form of abrasion that cuts away the damaged layer to reveal a flatter surface which reflects light evenly.
To machine polish a car, the following pieces of equipment and accessories are needed:
- The machine polisher itself – several types are available including dual-action, forced-rotation and rotary.
- Polishing pads – these can be made from foam, wool or microfibre.
- Polishing liquid – this is an abrasive liquid which lubricates the pad and allows the defects to be cut away.
- Microfibre towels – to remove the polishing liquid.
- Paint depth gauge – to measure how much clear coat paint the vehicle has and determine how much it can be polished.
- Inspection lights – powerful lights that can reveal defects so the paint condition can be assessed.
Preparing for Machine Polishing
Before a car can be polished, the paintwork needs to be thoroughly prepared. This is essential in order to remove contamination which could become lodged in the polishing pad and cause more defects instead of removing them.
Here are the key steps involved in preparing a car for machine polishing:
- The paintwork must be thoroughly washed.
- Chemical decontamination steps are performed to remove iron fallout and tar deposits.
- A clay bar is used to remove any remaining bonded contaminants and make the paintwork feel smooth.
- The car must be thoroughly dried and the paintwork inspected using a paint depth gauge and lights to assess the defects.
- Plastic and rubber trim must be taped off to prevent the polish staining these areas.
How to Machine Polish
Once the paintwork has been prepped, it’s time to start polishing. Here’s an outline of the general process:
- The polishing pad is attached to the backing plate on the machine polisher.
- Polishing liquid is applied to the pad to prime it.
- The polishing liquid is spread at a low speed on a small area of the panel using the machine polisher.
- The machine polisher speed is then increased and the pad is worked across the section in overlapping motions (vertical and horizontally).
- The polishing liquid is then removed with a microfibre towel.
- A panel wipe solution or isopropyl alcohol (IPA) is then used to wipe the surface with a fresh towel to remove any polishing oils that could be masking the defects.
- Inspection lights are used to assess the defect removal and finish of the paintwork.
The Test Section
All cars have different levels of clear coat “hardness” and defects, so the first thing that needs to be done is to test a small area to determine how the rest of the car should be polished. There are so many variables to consider including:
- The pad (microfibre, wool or foam of varying degrees of abrasiveness).
- The polish (different polishes or “compounds” also have different levels of aggression).
- Arm speed, polisher speed and pressure.
When machine polishing, varying levels of aggression can be used to address the condition of the paintwork.
Using an aggressive pad and polish will cut defects more efficiently, but can also leave behind some haze. This haze will then need to be refined using a softer combination.
If a one-step machine polishing process is being performed, there needs to be a balance to result in a good level of defect removal, but without sacrificing clarity.
If multiple stages of polishing are performed, then more defects can be removed, as the first step will act as the heavy cutting stage. The subsequent stages can be used to refine the finish and increase the clarity.
When we assess a vehicle, we can advise on whether a single-stage or multi-stage polish will be suitable for your vehicle based on your budget and requirements.
Benefits of Machine Polishing
The process of machine polishing offers several benefits including:
- Clear coat scratch and swirl mark removal.
- Increase in gloss and depth of colour.
- Prepares the surface for protection e.g. ceramic coating.
- More efficient compared to hand-polishing.
- Produces consistent results when performed properly.
- Can increase the resale value and desirability of the vehicle.
Does Machine Polishing Have Any Downsides?
Machine polishing involves removing a thin layer of clear coat paint from the surface, so there are risks involved if the process isn’t performed by a trained professional.
For example, more paint may be cut away than necessary (in more extreme cases the paint can even be “burnt through”). Also, a lack of knowledge and skill can produce a poor level of defect removal. In some cases, poor technique can even add more defects into the paint.
This is why it’s important to choose a professional with experience and training to make sure your vehicle is polished safely and effectively.
The process of machine polishing is also best performed in a controlled environment. Polishing a car indoors reduces the risk of dust settling on the car and contaminating the polishing pad.
Machine Polishing vs Hand Polishing
Hand polishing and machine polishing are both performed to improve the visual appearance of the clear coat layer of paint, but the effectiveness varies considerably.
Machine polishing involves more equipment and skill, however the level of defect removal is considerably better compared to hand polishing.
The process of hand polishing is very exhausting and time consuming, and the level of cut that can be achieved by hand polishing is very limited compared to using a machine.
Hand polishing is typically done by car enthusiasts looking to make a slight improvement to the finish of their car, but without the extra expense of machine polishing equipment and the risk damaging the surface due to inexperience.
Hence, machine polishing is typically done by professional detailers who have the right equipment, knowledge and skill. This is the safest option if you’re looking to safely improve the clear coat finish on your car.
What Happens After Machine Polishing?
After a car has been machine polished, it will need to be protected. This is because polishing removes any existing protection that is on the vehicle.
We recommend using a ceramic coating to protect the paintwork. This will lock in the finish and keep it glossy. Ceramic coatings also make the car easier to wash, keep it cleaner between washes, and last for several years.
Find out more about ceramic coatings by reading this guide, or visit our service page if you’re interested in getting your vehicle professionally machine polished and ceramic coated in Central Scotland.
Frequently Asked Questions
How long does machine polishing take?
Machine polishing can take anywhere from several hours to several days. It depends on the level of defects and the desired finish required. For example, getting a single-stage polish will be much quicker than a multi-stage correction. Larger vehicles will also take longer to polish.
How much does it cost to get a car machine polished?
Machine polishing packages typically start from £350 in the UK. This will generally just include an enhancement designed to improve the gloss. Single-stage machine polishing designed to remove light-medium defects generally starts from £500, whereas two-stage polishes start from around £700.
The choice of protection applied after polishing will also affect the package cost. For example, a long-term ceramic coating will be more expensive compared to a short-term wax or sealant.
For more information, please visit our price list.
What is the difference between compounding and polishing?
Compounding and polishing are both aspects of machine polishing. In a two-stage machine polish, the first stage will be the “compounding” stage. This involves using a heavier combination of pad and polishing liquid to achieve a good level of defect removal. The second stage will then be the polishing or refinement stage. This involves using a milder pad and polishing liquid combination to remove any light haze left behind by the compounding step.
The combination of these two stages allows a high level of defect removal, whilst still producing an excellent level of clarity.
What is the difference between a rotary and dual-action polisher?
Rotary and dual-action polishers are two different types of machine polisher.
Rotary polishers spin in a single direction, and are best for heavier defect removal in the first stage of the polishing process. Dual-action polishers also oscillate as well as spin, which means they don’t cut as aggressively, but can be used to refine the finish.
Do new cars need machine polishing?
New cars almost always need machine polishing in order to remove paint defects which are either created at the factory, or at the dealership when the vehicle is prepped for collection. These defects include:
- Clear coat scratches and swirl marks
- Chemical etching
- Sanding marks
Machine polishing removes these defects so your new vehicle actually looks new. The machine polishing process also prepares the paintwork for protection e.g. ceramic coating.
We offer several new car detailing packages in the Livingstone area, catering for clients based near Edinburgh and Glasgow.
Get Your Car Machine Polished in Central Scotland
Here at Machine Polishing – Central Scotland, we’re always happy to offer advice, explain the options clearly and help you understand the differences between services – even if you are comparing multiple providers.
Fill out the form below, or get in touch with us using the contact details in our footer, and one of our team will be happy to talk you through your options.
