Thursday, 9 May 2013

Polish and Compound

 [: Polishing is the process of creating a smooth and shiny surface by rubbing it or using a chemical action, leaving a surface with significant specular reflection and minimal diffuse reflection. When the surface is magnified thousands of times, it usually looks like mountains and valleys. By repeated abrasion, those "mountains" are worn down until they are flat or just small "hills." The process of polishing with abrasives starts with coarse ones and graduates to fine ones.]

I've spent many hours meeting and speaking with Engineers, paint chemists, product formulators, and abrasive manufacturers and polishing pad manufacturers and have gained insights into paint surface polishing that has afforded me an understanding of how all these things interact to form a process, on a scientific level paint polishing is the sum of all these parts.

Polish a paint surface  correctly (regardless of the machine we are using) the  goal is leave a series of scratching that is so fine that it becomes imperceptible to the naked eye.

The following ingredients are formulated in a polish;
·         Water - the more water there is in a compound, the softer it will be
·         Solvent - act as a carrier system and to make the other ingredients soluble. By adjusting the type of solvent, you will determine how long it takes the product to dry.
·         Abrasives - used to remove surface swirls and marring Abrasives can be soft or hard; the most common abrasive used is silica however; many formulators are also using aluminium oxide.
·         Diminishing abrasives - break-down due to friction  and then go on to burnish the paint to a bright shine
·         Non-diminishing abrasives - you polish until the defects are removed, not until the polish has diminished 
·         Surfactants - defined as a material that can greatly reduce the surface tension of liquids
·         Colouring - is used strictly for customer appeal, traditionally compounds are tan or olive in colour, so most manufacturers colour their compounds accordingly.
·         Fragrance - is only for customer appeal
·         Waxes - a small amount is used to produce gloss and fill small imperfections. And is sometimes used for surface lubrication

Emulsifiers - an oil/water emulsion is used to stabilize the product and make it easier to useA polish or compound is a specially formulated emulsion of materials designed to remove paint surface imperfections such as scratches, oxidation, stains, and acid rain etching. Compounds are formulated in both liquid and paste form, and generally contain more aggressive abrasives than are found in polishes. The compound step is usually followed a polish and then a polymer sealant, or a glaze, or and/or a Carnauba wax. 

Whether liquids or a paste, an apt description of a compound (800 -1500 grit); is ‘liquid sandpaper’ they are formulated from a few basic components: water, oil, and solvent, diminishing abrasives, surfactants, colouring and fragrance. Placing a small amount between your finger tips will no longer give an indication of compounds abrasiveness; this is due to the particles being emulsified in oil and not released until subjected to friction

The main ingredient in a polish or compound is the abrasive; wither diminishing or non-diminishing, the type of abrasive, their size, hardness and shape. The abrasive ability of a polish / compound is also affected by the type of lubrication (polymer, mineral oil, etc) used Some very abrasive compound polishes don’t feel abrasive to the touch because the particles are formulated in a water-in-oil emulsion for the cooling-lubricating process and are not released without friction or pressure / time.

These factors will determine what that polish will ultimately do to the paint surface, the larger the abrasive, the more aggressive it will be on the paint surface. The most common abrasive used is silica, which is much, much harder than aluminium oxide; however, many formulators are also using aluminium oxide.

Most good quality compounds and polishes contain abrasives and are either  silica or aluminium oxide, or a combination of both. Think of them as liquid sandpaper, buffered or cushioned in lubricating oils that are formulated with solvents, water and 0.3 –0.4µ (micron) abrasive particles,  in an emulsion that enables both cooling and surface lubrication, that spreads and tumbles the abrasives that diminishes with friction, or breakdown with pressure.

The paint film surface also requires occasional polishing to maintain a pristine paint film surface and to ensure that any accumulated microscopic contamination in the paint surface crevices does not cause paint staining and that this dirt is not sealed into the paint by the application of wax or sealant.

The use of abrasive type polish / cleaners should always be restricted to specific problems. Most original paint finishes are tougher on the outer surface than the layers underneath. The outer layer (which contains the paints UVR protection) should be preserved as far as possible. 


The more water there is in a compound, the softer it will be. That is the difference between a liquid and a paste compound. Neither is better than the other in terms of performance. It really comes down to what the detailer prefers.


There are basically three solvents that can be used: mineral spirits; kerosene; and naphtha. Mineral spirits is usually a quick-drying solvent that will make the compound dry quickly, speeding up the job. However, it will also increase the possibility of burning the paint if used incorrectly. Kerosene, on the other hand, is a slower-drying solvent that reduces the tendency to burn paint. It will, however, increase the work time with the compound.
What happens when the solvents vaporise?  Polish and many surface protection products are formulated with oils to enhance the surface or to nourish leather surfaces, neither of which is necessary
The purpose of oils is to provide lubrication, the amount used will determine the working time of the compound. Oils provide surface lubrication to help it spread; it is made into an emulsion with solvents that make the product into a pliable liquid. The emulsion of oil and its catalyst, a solvent, only require air to outgas as the oil/solvent solution will vaporise, sometimes a very thin film of oil is left on the surface, which is usually removed when the surface is wiped with isopropyl alcohol (IPA) this is important if the following product is a polymer as it won’t bond as an oil film acts as a buffer to the cross-linking process.

Oil-in-Water Emulsion

[ : a dispersion of small globules of one liquid in a second liquid with which the first will not mix, i.e. an emulsion of oil in water]

Synthetic polymers manufacturers are getting away from using petroleum distillate based silicones and are now using Polydimethylsiloxane silicones to produce a mild oil-in-water emulsion. Being primarily water based these are safe for all types of pant and are biodegradable.

Chemists also use these water-in-oil emulsions to reduce emulsion particle size, to stabilize the emulsions, and to improve spreading and coverage of the polymers products. Emulsion polymerisation takes place in an emulsion typically incorporating water, monomer, and a surfactant. The most common type of emulsion is an oil-in-water emulsion, in which droplets of monomer (the oil) are emulsified (with surfactants) in a continuous phase of water.

If the polymerisation is carried out in the absence of surfactants, it is generally known as a suspension polymerisation. The advantages of emulsion polymerisation include: more complete surface coverage to prevent contact between unprotected areas, viscosity remains close to that of water and is not dependent on Covalent (molecular) weight and the final product can be used as is and does not generally need to be altered or processed.


Emulsifiers and emulsions can seem like mysterious concepts but actually are very common. Milk is an emulsion of milk fats and solids held in suspension by an emulsifier called casein. Oils and polymers are often suspended in an emulsion and used as a carrier system in waxes and polymer sealants.

Oil will not spontaneously mix with water, but the presence of a surfactant provides a decrease in surface tension that allows the formation of small droplets of oil in the bulk of water (or vice versa)Compounds, polishes, waxes and sealants are most commonly comprised of very tiny droplets (emulsion) of solvents, abrasives and active ingredients held in suspension in a water solution by emulsifiers

Surface Filling / Masking Abilities

Every polish that uses oils or polymers for lubrication will fill surface marks that are not removed and mask defects. If you don’t remove the lubricating oils (Anhydrous Isopropyl (99%) Alcohol (AIPA) wipe-down then you are by passing the post polish inspection and the oils left behind will mask the defects.

Note – some polishes contain specific products (i.e. Kaolin (China clay) or Diatomaceous earth) to mask surface marks, this type of filler will also be removed by the IPA wipe-down process.


Abrasives are made from chromium oxide, aluminium silicate, zirconium silicate and carbides; their abrasive ability depends on the shape of its particles, not necessarily its size. A medium size, spiked abrasive will tumble and dig. However, a large round crystal won't leave a deep scratch.

A large hard abrasive may also be brittle. It will cut once and lose its edge, while a softer small abrasive will hold its edge and keep on cutting. Many smaller abrasives have wedge shaped edges protruding from triangular crystals. These can easily slice through an oxidized layer of paint

Polishes are a very essential product for the overall appearance and condition of the paint finish. There are abrasive polishes formulated to remove paint finish issues such as oxidation or other paint surface imperfections such as surface scratches. Light polishes contain either mild abrasives and / or a chemical cleaner (solvent) most mild abrasive polishes will remove medium scratches or surface imperfections, whereas a strong abrasive compound polish  rely both on a chemical cleaner (solvent) l and mechanical abrasives to rectify more serious paintwork issues.

Proper washing and drying techniques are the best way to avoid the need for polishing. Using a chemical paint cleanser versus polishing on a clean finish to simply remove old wax/sealant is another. And always follow the rule of using the least abrasive polish and pad combination (working smarter not harder)
Polish and Wax are very different and should not be confused, although the retail industry has blurred them together in marketing.

This is not generally possible because the substances perform separate functions; in general terms a wax is used for protection and a polish is abrasive and used for surface correction. The word ‘polish’ is used because when you apply wax to a vehicle you are ‘polishing the car’

[Detailers] A polish is an abrasive product that removes imperfections and levels a surface to enable the light to reflect evenly.

[General public] The word shine is also used in the context "I polished with a wax to make it shine" hence the confusion between the two.

Paint Polishes and Protective Coatings

·         Compound – an aggressive grade of polish used to remove deeper scratches and for paint renovation

·         Polish – an abrasive compound that removes surface scratches and impurities, it provides shine and prepares it for a wax or sealant protection.

·         Paint Cleaner (pre-wax cleaner) – a chemical cleaner that contains mild abrasives (i.e. Kaolin (China clay) or Diatomaceous earth ) that is used to clean a paint surface but they will remove wax residues, embedded dirt and light stains from your paint , but they will not remove ingrained surface scratches. Use paint cleaner after detailing clay and before waxing.

·         All in One) – very similar formulation to a paint cleaner, the main difference is that an AIO type product provides limited surface protection

·         Glaze – used by detailers for show car to obtain maximum light reflection. They produce a “wet" look to the surface with oils to maximize surface gloss and may contain fillers (Kaolin or China clay) to hide minor defects not removed by polishing or for use when the paint is thin and you don't want to remove any more, even if it is microns. A glaze is a very fine (usually) non-abrasive polish. Some glazes are safe to use on fresh paint, as they allow fresh paint to outgas. They will provide little if any surface protection.

·         Wax – an organic or synthetic protective coating that is applied to the exterior surface of an automobile to improve shine and prevent oxidation

·         Sealant – a polymer sealant comprises an open linked molecule, which forms a bond with the paint, this is the main reason for their durability; these open linked polymer molecules join together to create an elongated mesh like effect that reflects light efficiently due to their inherent flat surface. Because they are usually very transparent they transmit the surface colour faithfully, but they have very little depth resulting in what is perceived as a very bright, flat silver glow

·         Quick Detailer - Detailers spray (QD) have many uses; to aid in final drying to remove water spots, used with Zaino (Z6) to help ‘smooth-out’ finish between coats of sealants, it also removes smearing from the overuse of product. Use a 1:1 solution of a detailing spray and distilled water as it makes them easier to apply and more economical. To remove heavy dust use Optimum No Rinse (ONR) a waterless wash as it will provide a lubricant that a detail spray doesn’t.

Waxing or applying a polymer sealant to a surface that has not been properly cleaned will only result in a shiny layer over dull, dirty paint - not the deep smooth, optically perfect crystalline shine that is obtainable.


The ability for a polish to "cut" depends on the shape of its crystals or particles, not necessarily its size. A medium size, spiked abrasive will tumble and dig. However, a large round crystal won't leave a deep scratch.
Aluminium oxide has a hardness factor MOHS 9 and will not break down during polishing. Rather the larger clusters of aluminium oxide reduce in size.

A large hard abrasive may also be brittle. It will cut once and lose its edge, while a softer small abrasive will hold its edge and keep on cutting. Many smaller abrasives have wedge shaped edges protruding from triangular crystals. These can easily slice through an oxidized layer of paint
Types (Grades) of Polishes
A surface scratch that will `catch' your fingernail is approximately 0.04 Mil (1.0 µ Microns) deep will usually require wet sanding and refinishing. Other than that > 1000 grit scratches can be removed with a polish/compound and a machine polisher.

The ability for a polish to "cut" depends on the shape of its crystals or particles, not necessarily its size. A medium size, spiked abrasive will tumble and dig. However, a large round crystal won't leave a deep scratch.
A large hard abrasive may also be brittle. It will cut once and lose its edge, while a softer small abrasive will hold its edge and keep on cutting. Many smaller abrasives have wedge shaped edges protruding from triangular crystals. These can easily slice through an oxidized layer of metal.

Liquid polishes tend to perform better than pastes because they allow you to use the oxidation you're removing as an abrasive. The oxidation will be no coarser than the abrasive in the polish, and since aluminium oxide is second only to a diamond abrasive, it makes an ideal cutting compound.
      Compounds -  are the most aggressive, most abrasive type of polish and will remove the largest amount of clear coat in the shortest period of time. Compounds are commonly used on severely neglected vehicles and to clean up wet sanding marks. Compounds will almost always leave behind some marring, hazing, or holograms and should always be followed up with a finer polish or multiple polishes.
      Abrasive Polishes – the most polishes that correct moderate paint imperfections fall into the category of an abrasive polish. They are a step below compounds in terms of aggressiveness and usually do not finish down as well as a finishing polish. On most paints, it is recommended to follow up an abrasive polish with a finishing polish to remove any micro-marring, hazing or holograms as well as increase the depth and gloss. Some abrasive polishes are capable of finishing on certain paint.

     Diminishing Polishes - will remove very minor imperfections in the paint, such as micro-marring, hazing and holograms. A finishing polish is formulated with a very mild abrasive that finely polishes the paint surface and effectively enhances light refraction and reflectivity. They are also used to burnish (jewelling) the paint to achieve an exceptional level of gloss and depth.
             Paint Cleaners - are designed to enhance the depth and gloss while properly preparing the paint for a sealant or wax. Sometimes paint cleaners can have micro abrasives or they can be non-abrasive. They typically will not remove imperfections that require levelling the clear coat, but can remove some oxidation and mineral deposits.

         Always choose the least intrusive product, it is preferable to polish 2-3 times to restore the paint film surface than to use an unnecessarily abrasive machine polish / foam pad combination. Before commencing polishing do a test panel on the car, once you have achieved the desired results with the chosen polish / pad combination proceed

Difference between Diminishing and Standard Abrasive Polishes

Diminishing Abrasives Technology

A non-linear abrasive that require kinetic (or dynamic) friction - while the majority of polishes on the market use a form of diminishing (non- linear) abrasive, which you polish to a ‘haze’ (when a polish "flashes" from a liquid paste to a light semi-dry haze, much like a coating of Vaseline®) the diminishing polish has then broken down and is ready for removal. Diminishing abrasives, as the name suggests; t he abrasives become smaller with friction, and therefore go from removing paint defects to polishing the paint, which produces the shine.

If you don't break them down sufficiently, you are just grinding those abrasive particles into your paint, without polishing it, which can leave behind marring and other paint surface imperfections. So it’s important to know when a polish has broken down because if you take it too far you will re-introduce surface marring. During the polishing process, trace amounts of paint and / or oxidation is removed; this can cause the debris and the polish to “clump” together. This can cause a haze to the paint surface, a wipe-down or a paint cleaning product will eliminate this.

Pros - Menzerna diminishing abrasive polishes are formulated with a long lasting lubricant. The abrasives break down before the lubricating oils dry out, thereby giving polish a longer working time and producing less abrasive dust and avoiding dry buffing.

Cons - Menzerna lubrication oils can be really resistant to removal; it may take 2-3 IPA wipe-downs.

Non- Diminishing Abrasives Technology 

A linear abrasive that require time and pressure - unlike diminishing abrasives, which require kinetic (or dynamic) friction to enable the abrasives to 'break-down to obtain the best possible finish (and avoid holograms) non-diminishing abrasives react very differently. It will be as abrasive as you want it to be, time and pressure applied (linear abrasive) being its working criteria.

Linear abrasive polishes / compounds provides a constant cutting abrasive, as the abrasives  remains uniform in size throughout the polishing process, so you need to check the surface often. They should be used with a cutting foam or wool pad until the defects are removed (1200 – 1500 RPM) but do not allow the polish too completely dry (as this will also produce holograms) and ensure that pad surface is cleaned by removing paint / polish debris regularly This type of compound / polish process usually requires subsequent polishing step(s) to further refine the finish and to produce a shine

Cons - the lubricating oils dry out, thereby providing a shorter working time, producing more abrasive dust and the possibility of dry buffing

Amount of Polish

Place a small amount (approx 3 x 1/16th-inch diameter or a 1 ½ x 1 ½ -inch X) of polish onto the centre of a clean primed pad. Approximately 1.5 – 2 oz for a mid-sized vehicle

Polish / Compound Application

If you were to apply polish to a body panel, and then place a pad on the surface and turn the machine on, it would be very difficult to control and will produce hazing. This is due to most of the pad being "dry". Polishes and compounds appear to work better when the foam pad is ‘primed’ some things to note about pad 
priming: the cutting ability is increased, a better finish is obtained, it reduces any product ‘flashing’ problems, it produces a more even finish and the polishing machine is  less likely to hop.

Use a very slightly distilled water dampened pad, not too wet (otherwise the polish will clump); then spread the polish / compound over the pad evenly and ensure it is absorbed into the foam, apply some pressure to the surface and scrape any excess product from the pad

Apply the compound or polish to the surface and spread the polish using the foam pad with the (Orbital Polisher) machine off. This coats the pad and the surface being polished with product to prevent scratching or hazing the finish, then place the foam pad flat on the surface and turn the machine on. Do not, under any circumstances, turn the polisher on with any portion of the foam pad dry as this will produce hazing.

Most polishes are formulated by emulsifying a powdered abrasive in a carrier system (oil / solvent) the right amount of pressure / friction heat is vital to allow the polish / compound abrasives to level the paint surface and remove surface scratches / marring

Dry buffing

Dry buffing (polishing) refers to when the polishes lubricants run out; non-diminishing abrasives will start to emits a white dust, diminishing abrasives start to become translucent (similar to Vaseline on a paint surface). Once you polish much beyond these points is when friction from dry-buffing can lead to you creating fine scratches and dullness or even burning the paint.

Polish Methodology (polishes and pad selection)

Diagnosis is the key; not guesswork; examine the vehicles bodywork, a ‘bag-test will ascertain the need for detailer’s clay, and a 3M Sun Gun or a Brinkman light will help you find any evidence of surface blemishes i.e. swirl marks and scratches.
The most important first step in the process of paint surface detailing is diagnosing the paint surface; density of clear coat (hard or soft) or single stage paint, surface condition; ascertain the severity of the surface blemishes with an inspection light and the paint thickness available. The paintwork should be evaluated with a paint thickness gauge to see what thickness of clear coat remains before you decide how much paint renovation can be safely carried or wither paint preservation would be the appropriate option, before you proceed, measuring with a paint thickness gauge will dictate the choice and abrasiveness of polish / compound for correction or renovation level required or indeed possible

Always follow the rule of starting with the least abrasive combination, i.e. a machine polish and the least aggressive foam or wool pad (working smarter not harder) The most important first step in the process of paint surface detailing is diagnosing the paint surface; density of clear coat (hard or soft) or single stage paint, surface condition; ascertain the severity of the surface blemishes with an inspection light and the paint thickness available.

Measuring with a paint thickness gauge will dictate the choice and abrasiveness of polish / compound for correction or renovation level required or indeed possible. Assess the correction level working through the range of polishes from the lightest abrasive upwards until the desired level of correction is reached. Selecting the correct pad / polish combination for the vehicles paint / defects can take just as long as the paint correction process

When removing defects from the paint surface, consider not only which polish / compound you'll be using, but how you'll be using it. You choice of machine speed, pad construction, pad size and applied pressure will all impact the abrasive abilities of the polishing liquid.

Decide on a one, two or three step polishing routine and select a suitable pad. After testing a section to confirm this method, Select an area of 18 x 18-inches and tape it off with painter’s tape, as this is an optimal working section to perform a product test spot; this will help establish a process that will produce the best possible finish, once this is established repeat the process over the entire paint surface.

Select a ‘typical’ area - (one that represents the type of defects that you want to remove) and starting with the least abrasive polish and / pad combination and then proceed until the defects are removed. This is the polish / pad combination you’ll need to use

Relevant Articles

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