Car Care & Detailing Guides

Using appropriate products and techniques gained from many years of experience, UF has published a series of car care guides with the car enthusiast in mind. With careful application and attention to detail, you too can correctly look after your car, make it look amazing and then keep it that way. Protecting your investment starts here …

Car Care & Detailing Guides Published by Ultimate Finish

10. Inspection & Appraisal

Prior to carrying out any kind of polishing it’s a good idea to thoroughly inspect your paintwork. To do this requires high intensity lighting, to properly illuminate imperfections. An understanding of the different types of blemishes and the extent to which you can impact their appearance is required along with an appreciation for the functionality of clearcoats. A little time spent researching these areas will potentially prevent expensive mistakes.

10.1 Inspection (The Importance of Good Lighting)

10.1 Inspection (The Importance of Good Lighting)

Before starting the refining or correcting (polishing) process, it’s essential to have a clear picture of the condition of the paintwork and the blemishes that need to be addressed. Too often time is spent polishing paintwork to what appears to be perfection, only to take it into bright sunlight and discover a myriad of spider web-like swirls and or holograms.

Lights list their intensity in lux and/or lumens, so it’s useful to understand the relevance. Lux is light intensity as perceived by the human eye and is measured in lumens. 1 lux = 1 lumens per metre squared. Full daylight is between 10,000 and 25,000 lumens. Direct sunlight is around 100,000 lumens. If your lighting source lists its ability in lumens or lux – the higher the number, the more imperfections it will show!

Colour Rendering Index (CRI) is a measure of a light sources ability to discriminate between different colours. The maximum CRI possible is 100. A low CRI will render colours a different shade to their real colour. The higher the CRI, the more accurate the colour. Fluorescent lights of the types found in most garages and workshops have a CRI of around 50. LEDs have a CRI of around 80. However, a high CRI does not necessarily mean it will show up more blemishes on paintwork.

There are 3 main types of lighting:

Fluorescent lights work effectively for general purpose work, but tend to be too diffuse to adequately show up all of the inherent paint defects. Typically they are ceiling mounted.

Halogen lights will only show up certain defects as they have a limited spectrum resulting in difficulty picking up subtle differences in colour. They also generate a lot of heat, so working under them for prolonged period gets quite uncomfortable. Typically they are available as one or two spot lamps mounted on tripods for easy positioning close to the panel being worked on.

Metal Halide lights, although initially more expensive, last up to 30 times longer and are up to 4 times brighter than the equivalent halogen lights. They use 75% less power, making them an ideal choice for detailing studios.

For close up inspection, a high quality LED torch (swirl finder) will focus an intense beam onto a specific area, with a brightness similar to direct sunlight. Ideally it will have a ‘fish-eye’ lens to focus the beam on to one area without causing a ‘dark spot’ in the centre – caused by a lack of overlap of light spill as a result of the positioning of the bulbs. A good LED will show up any particular areas that require further attention and allow you to accurately work on them.

Browse Inspection Lighting

10.1 Inspection (The Importance of Good Lighting) PDF

10.2 Understanding Paint Defects

10.2 Understanding Paint Defects

Before starting to correct and / or refine your paintwork by hand or machine, it’s a good idea to identify each problem and what you can realistically expect to achieve. Whilst many imperfections will polish out with the correct tools and techniques, others will not. This section is designed to define the different types of paintwork problems and give an idea as to what can be done to correct them.

Oxidation – over time, harmful Ultraviolet (UV) rays make paintwork look dull and chalky – blacks appear grey, reds appear pink, etc. Oxidation was a particular problem for older paints – modern paint colour pigments are becoming increasingly sophisticated and new technologies mean clear coats have been engineered to better protect pigments.

Oxidation can be removed using an abrasive polish working by hand or with a machine polisher. By hand will of course, take longer!

Swirl marks – usually incurred during the washing and drying process, or picked up whilst driving. Swirls present as a ‘cobwebbing’ pattern across the paintwork. The more cobwebs present, the more light is scattered. Swirl marks play a significant role in the loss of gloss from paintwork.

Swirl marks can, dependant on the severity, usually be removed by hand with a suitable abrasive polish, however working with a machine polisher will give better results much faster.

Fine scratches – present in the upper most layer of the clear coat, fine scratches are usually a result of dirt and grit being rubbed over the surface mainly during the washing and drying process, but can also be caused by dirt and dust whipped up by high winds. They’re usually defined as ‘fine’ if you cannot catch your fingernail in them.

Fine scratches will normally polish out. If there are only a couple of fine scratches using a proprietary scratch remover will work well. However, if the scratches are more prevalent then a machine polisher is a more able method of removing them.

Random Deep Scratches (RDS) – these deeper grooves cut through the clear coat and paint colour, down to the primer or sometimes, even to the bare metal. RDS can be spotted easily and running a fingernail along will cause the nail to catch in the groove.

These types of defect cannot normally be machine polished out completely, however their appearance can be significantly reduced by rounding off the edges of the groove, thereby affecting the way they reflect light, minimising their visual impact.

Holograms – also known as buffer trails, are caused by poor machine polishing techniques, even on brand new cars! These leave a blurry swirling effect on paintwork causing it to look dull and greasy.

Holograms are usually fairly easy to remove using the correct combination of machine polisher, pad and compound. Attempts to remove buffer trails through hand polishing is unlikely to work.

Stone chips – pitting in paintwork as a result of a high velocity collision of a hard stone with the bodywork. These present as fairly rounded spots and they usually look greyish white in colour – this is the primer showing through.

Stone chips go deep to the primer and actually are the result of several layers of clear coat and paint having been dug out of the bodywork. These will not machine polish out. Specialist products are required to fill in stone chips to reduce their appearance.

Bird dropping etching – birds usually do their business on top of fairly flat surfaces presented most directly to the sun. As paintwork is heated, it expands around the bird droppings and as it cools it contracts. This combined with the acidity of the droppings causes severe etching on the surface of the clear coat.

Acid rain etching – acid rain is caused by sulphur dioxide and nitrogen oxide, produced as a result of  fossil fuel combustion, volcanic eruptions or even lightning strikes – combining with water to produce acid rain. Carbon dioxide in the atmosphere combines with water to form carbonic acid. These all wash out of the atmosphere with rain and react with clear coats to leave irregularly shaped patches, visible most clearly in direct sunlight and on darker coloured vehicles.

There are varying intensities of acid rain etching and whilst some will polish out with the right tools, if the rain has a particularly strong acidic composition or has been combined with some other factor, such as volcanic ash, there are occasions when this type of blemish will not polish out fully. The best way to guard against this type of damage is to ensure your vehicle has been protected with a last step product (LSP) such as a natural carnauba wax or a nanotechnology based glass coat sealant.

Water spot marks – PCC (precipitated calcium carbonate) from rain, or impurities in rinse water leave deposits on the paintwork if the vehicle is not properly dried. As with bird droppings, as paintwork expands and contracts around the water marks, the edges become etched into the clear coat and usually require machine polishing to remove.

For a more in-depth explanation of paint and clear coat, please refer to the following blog article – Understanding Modern Automotive Paintwork

10.2 Understanding Paint Defects PDF

10.3 Paint Thickness - Why Is It Important?

10.3 Paint Thickness – Why Is It Important?

Before commencing any form of machine polishing it is advisable that you know the depth of the paint. Some primer, paint and clear coat combinations are very thin, some are thicker. As machine polishing removes blemishes by removing layers of clear coat, it’s a good idea to know how much you have to play with to prevent accidental burn-through.

Paint and associated layers are measured in microns. 1 micron = 1000th of a millimetre. Modern clear coat depths range from around 32 microns to 102 microns. Machine polishing will remove 2-3 microns of clear coat (unless very abrasive compound / pad combinations are used). This is usually enough to remove most imperfections (refer to 10.2. Understanding Paint Defects for further information).

To measure your paint use a Paint Depth Gauge. There are many different models available and typically, the more sophisticated the gauge, the higher the price tag. All of them give the reading for the clear coat and the paint layers combined. Some gauges only work on painted steel panels, others will work on other, non-conductive substrates such as brass, aluminium and plastic – particularly handy if you have colour coded bumpers or a ‘plastic’ car, such as a Smart car!

Taking paint depth readings can yield some surprising results, particularly if the car was bought as a ‘used car’. Sometimes a panel will give a thicker paint depth reading, indicating a previous re-spray – something that may not have been revealed at the point of sale.

Browse Paint Depth Gauges

For a more in-depth explanation of paint and clear coat, please refer to the following blog article – Understanding Modern Automotive Paintwork

10.3 Paint Thickness - Why Is It Important? PDF

10.4 Clearcoat Lacquers Explained

10.4 Clearcoat Lacquers Explained

Clearcoat Lacquer is the final layer that is applied to the painted surface of your vehicle. Typically it is between 32 and 102 microns in depth and its primary function is to protect the underlying paint base colour. Clearcoat has to be chemically stable when exposed to UV radiation, it has to provide gloss and it has to cure hard enough to offer some protection from swirls and scratches.

Modern clearcoat technology is advancing rapidly and the age of self-healing clearcoats is not that far away. In the meantime, understanding how present-day clearcoats function is important prior to picking up a machine polisher.

Clearcoats are colourless – the colour of your car is determined by the paint layers underneath the clearcoat. This transparent layer has to combine the elements required to provide scratch-resistance, UV stability and gloss, all into one solution. Significantly, the elements used to provide UV resistance are lighter than the other elements, so as the clearcoat cures the UV resistant elements naturally rise to the upper layers whilst the heavier elements settle towards the bottom.

Each time a clearcoat is machine polished, around 2 -3 microns of the upper part of the clearcoat is removed. It doesn’t take much machine polishing before the UV protective elements start to become degraded. Additionally, many car marques actually state paint warranties are invalidated if more than 25% of the original clearcoat has been removed. This means if the clearcoat is 80 microns thick, only 20 microns needs to be removed before the warranty is voided. If machine polishing session removes 3 microns – six or seven machine polishing sessions could conceivably void the warranty! This should be taken in to account before too much enthusiastic machine polishing begins!

For a more in-depth explanation of paint and clear coat, please refer to the following blog article – Understanding Modern Automotive Paintwork

10.4 Clearcoat Lacquers Explained PDF

10.5 How Hard Is My Paint?

10.5 How Hard Is My Paint?

Amongst the many terms used by professional detailers when referring to or discussing machine polishing automotive paintwork, the phrases ‘hard’ and ‘soft’ come up frequently.

Whilst it is generally accepted each car manufacturer tend to have a certain type of paint, it’s not always the case and therefore should not be taken for granted. Take, for example, German marques, such as Mercedes, Audi, BMW and Volkswagen. Typically, their paint is moderately hard to very hard. Japanese marques, such as Subaru and Honda generally have medium soft to very soft paint. These generalisations work as a rule of thumb, but, as any detailer will tell you, if you work on enough cars you’ll soon realise there are always exceptions, especially if the vehicle has been subject to a re-spray!

Hard paints tend to be more labour intensive to correct, but once corrected are fairly easy to refine. Soft paints on the other hand are easier to correct but can be tricky to refine. With some very soft paints, even a light wipe with a microfibre to remove polish residue can be enough to re-introduce fine scratches!

How does your paintwork hardness affect you? Depending on how hard or soft the paint is will determine which machine polishing pads and compounds will work most efficiently for you.

Generic Guide to Paint (Clearcoat) Hardness By Automotive Marque:

Soft Paint

Intermediate Paint

Hard Paint

Alfa Romeo

Aston Martin

Audi

Daewoo

Bentley

BMW

Ferrari (up to 2005)

Citroen

Lamborghini

Fiat

Ferrari (2005 onwards)

Mercedes Benz

Honda

Ford

Mini

Lexus

Jaguar

Porsche (up to 1998)

Mazda

Jeep

Subaru (up to 2001)

Mitsubishi

Land Rover

TVR

Nissan

Lotus

Volkswagen

Suzuki

Maserati

Toyota

Peugeot

Vauxhall (up to 1998)

Porsche (1998 onwards)

Renault

Rolls Royce

Saab

Seat

Skoda

Subaru (2001 onwards)

Volvo

10.5 How Hard Is My Paint? PDF

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