John’s thoughts on polishing…

February 28th, 2011

John's thoughts on polishing... probably the most complex car care subject of all.

In the third installment of my blog, I’ll look at my training regarding polishing and offer my thoughts on this massive topic. This could be lengthy…

The initial points that Rich and I discussed were basic, but possibly much overlooked: what exactly is car paint and, crucially, how much paint depth do cars typically have? I was aware that total depth is usually pretty thin, but only when you have a laboratory reference shim in your hand do you realise that 100 microns is not a lot. For reference, a typical sheet of paper is around 70 microns thick.

Paint defects generally comprise any damage that has broken the top layer of paint (usually termed the clearcoat) and damage such as stone chips and swirl marks are probably the most common. For the purposes of this blog, I’ll refer to any abrasive product as a polish and any non-abrasive product as a glaze in the following discussion.

In a nutshell, polishing removes some of the clearcoat and essentially lowers and flattens the finish, thus removing any paint defects present. This point is vital as polishing will always remove a fraction of the clearcoat. Polish too often and too much clearcoat will be removed, resulting in paint system failure. It’s generally accepted that removal of up to 25 % of the clearcoat is safe over the lifetime of the average car. Paints vary in terms of hardness and resistance to scratches and chips, and car manufacturers select paint type based on the properties they place most importance upon.

An alternative to polishing out fine swirl marks and other minor defects is to use a glaze. Imagine the paint finish sideways on. The defects will look like valleys. Glazes work by filling these valleys up with oils and clay particles, which reduces the visibility of defects. As glazes are non-abrasive, they do not remove any paint. The downsides of using glazes are: (a) defects are only hidden, not removed, and; (b) the effect is temporary, because the fillers will erode away over time, re-revealing the original defect. It should be noted that glazes must always be topped with good sealant or wax protection, otherwise they will be quickly washed off.

Polishes, as I’ve mentioned, remove paint and, in doing so, will remove defects. A polish will contain very finely milled abrasive particles, generally of aluminium oxide, which are worked across the paint surface to remove some of the clearcoat. In my mind, their mode of operation is very similar to how a sponge works (or doesn’t!) on paint; cleaning a car with a sponge results in particles of dirt being trapped between the paint surface and the face of the sponge. This induces swirls and scratches.

Polishing, in my head at least, works in a similar way: the particles in the polish are trapped between the paint surface and the polishing pad and worked across the paint. The important difference is, the polishing particles are very finely milled and are designed to be used to cut the paint surface. When polishing, I find it useful to think about what is actually taking place and in my, perhaps slightly odd, mind, I imagine a microscopic image of the particles being ground into the paint surface and some of it being removed (sometimes I actually imagine each particle is a Pac-Man, eating tiny pieces of the paint surface – I also think I shouldn’t be allowed out in public).

Polishes contain oils and other chemicals to ease their operation. Many polishes utilise diminishing abrasives, meaning the particles will break down when they are worked into the paint. The smaller they get, in theory, the more refined the finish will be. Most polishes start to turn see through when they have been worked sufficiently and this occurs when the diminishing particles have, unsurprisingly, diminished.

More aggressive polishes can contain a higher proportion of abrasives or larger particles which take longer to break down and offer a higher level of cut. They will also, obviously, remove much more clearcoat than a less aggressive polish. Some may contain microscopic particles that do not diminish and will simply continue to abrade for as long as they are worked (up to a point). This type of non-diminishing particle offers differing results based on speed of work, pressure and pad type.

A further variable to consider is the choice of pad. A very soft pad working a very aggressive polish is not an advisable combination as the pad will not force the particles against the paint with sufficient pressure. However, a soft pad is ideal for use with a finishing polish as its softer nature will offer less cut and will allow the finishing polish to bring out a superior level of shine.

A very stiff pad is ideal for working an aggressive polishing compound as it will allow more pressure to be applied, forcing the polish to cut the paint harder. However, a very stiff pad will tend to have an abrasive texture and simply working the pad itself into the paint will lead to some cutting effect. Therefore, stiffs pads are not well suited to producing exceptional paint finishes and are generally not recommended for cars with soft paint.

Pad selection is something of a minefield, made more difficult because each manufacturer tends to grade and name their pads in slightly different ways. For example, comparing polishing pads from two different manufacturers is not necessarily comparing like with like.

The principles of polishing are the same whether working by hand or machine. Working by machine, assuming guidelines are properly followed, will result in faster results and probably a higher level of defect removal as polishes can be worked harder and faster than is possible by hand. However, polishing by hand can still bring about excellent results on soft and intermediate paints, but it will be much harder work.

During the hands-on part of my training, I tried working various glazes into an old scrap BMW panel both by hand and machine to see (a) how much defect masking is possible, and (b) whether there is any difference working them by hand and machine. I then went on to test various polishes from very fine finishing polishes through to very aggressive cutting compounds, by hand and then by machine.

The glazes, on the whole, did a reasonable job of filling lighter defects and are thus ideal for masking lighter wash marring. Some worked more effectively by machine, while for others, using a machine made little difference compared to hand use. All left a noticeably smoother paint finish, probably as a result of the glazing oils contained within them.

The finishing polishes, worked by hand, didn’t remove a tremendous amount of defects but there was a noticeable difference in the paint’s appearance. Using the more aggressive polishes by hand led to some interesting results: all removed defects to varying degrees, but interestingly one of the most aggressive products, which I suspected could not be worked hard enough by hand, yielded excellent results.

Working the same polishes by machine led to a similar pattern of results but the defect removal was greater and the working time was much reduced – plus my arms were happier! The most aggressive polish, best described as liquid sandpaper, removed all but the deepest of scratches but did leave its own light scratches; the abrasives were so strong that they themselves marked the paint even when the polish was worked fully and all particles were broken down. This micromarring effect was easily removed using a finishing polish.

The next stage, and one which I was rather unsure about, was wetsanding. After a demo from Rich, I stuck a 2000 grit Mirka Abralon disc onto the polisher and started some serious clearcoat removal. I worked the 2000 grit disc, then refined with a 4000 grit disc and finally switched to Meguiar’s’ #105 to remove the matt-looking haze. The benefit of using the Abralon discs is that the material features uniform abrasives: sandpaper tends to have some naturally larger particles which will inflict sanding scratches. After refining with #105, almost all the scratches were removed: the ones that remained were exceptionally deep and had probably penetrated the total depth of the clearcoat.

The paint on the scrap panel was particularly hard and deep (being older it was solvent-based), but despite this, the amount of clearcoat removal was in the range 5-8 microns. Modern, water-based paints, and softer paints, would have seen an even higher amount of paint removed.

To sum up then, my very own golden rules of polishing:

• Don’t polish until you absolutely have to – consider glazing instead;

• Pick the least aggressive polish required to get the job done and minimise paint removal;

• Select your pad carefully, whether working by hand or machine.

My next article will be about paint protection and will be published next month, just in time for the onset of the better spring weather. As always, if you have any questions or comments please feel free to fire away.

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13 Responses to “John’s thoughts on polishing…”

  1. Grant Broughton says:

    Hi, I enjoyed reading your post, but I have always been told that glazes remove a small amount of the clearcoat due to the rotation and cutting action of the pad; is this incorrect? What’s the least abrasive and highest gloss polish for paint correction, as opposed to masking swirls, on a white car?

  2. Hi Grant, thanks very much for your comments. Glazes can cut ever so slightly depending on how they are applied, but glazes themselves, on the whole, have no abrasives. We almost always apply glazes by hand, generally with a microfibre pad and the cut from this pad is negligible. We find glazing by hand is often faster (no need to mask up, etc) and the results in many cases are all but identical to working by machine.

    Applying a glaze by machine with a very soft glazing pad may remove a tiny amount of clearcoat, but it is likely to be fractions of a micron at the very most. Obviously, using a stiffer pad will induce more cut. The highest gloss polish for swirl removal depends on paint hardness rather than colour. If you’d like to e-mail me directly telling me what type of car you have with a description of the paintwork condition, or, if possible, with some photos attached, I can recommend a pad and polish combination to suit. Regards, John.

  3. Bart says:

    Very nice read! When using the Abralon discs on a scrap panel (Renault) I got about the same levels of clearcoat removal. It seemed to me that after two passes the discs were degrading very fast. Don’t get me wrong, they do do a great job in removing defects, but aiming for higher figures in depth removal requires using your hands, which is not always an option, and doesn’t give a nice even leveling effect. But that doesn’t really matter when you’re spending your Sunday shining up a scrap panel! Loved this – “sometimes I actually imagine each particle is a Pac-Man, eating tiny pieces of the paint surface.”

  4. Hi Bart, the discs will obviously degrade with usage but keeping the panel lubricated and keeping machine speed slightly lower will increase their longevity. Were you working via dual action or rotary? If you removed up to 8 microns via this method, and defects still remained, it’s probably best to stop there and avoid removing further paint depth. There comes a point where defects are only really going to come out with very high paint removal and in those cases, personally, I’d leave the defects in, focusing instead on the future of the paint.

    Wetsanding really is something to be avoided wherever possible and in many cases is unnecessary, certainly in the quest to remove ‘orange peel’ it can be a fruitless task (pun intended) as wetsanding can remove a high percentage of paint but the orange peel can be contained within the base layer of paint, from where it’ll never be removed. Whilst this is frustrating, it’s more and more common with modern paints but is something we may have to become used to. Regards, John.

  5. Bart says:

    Thanks for the reply John. You’ve made a great point there; I was only pushing the limits on a scrap panel. There is no way I would take it to that level on my own car. The random deep scratches I was trying to remove were created by myself, working the Mirka’s by DA then polishing using wool pads on the rotary. That would explain the 8 microns I think!

  6. Henry Gray says:

    Hi John, I am new to detailing and frightened that I might damage the paint. I will be taking delivery of a new Mitsubishi ASX finished in Amethyst Black Pearlescent in the next week or so and would like your advice on the best methods and materials to use. I would like to get a perfect finish and all work will be carried out by hand. All advice will be greatly appreciated. I have a lot of time but not much money left!

  7. Hi Henry,

    Thanks for your comment. If your car is brand new, I will assume it will be in pretty good condition (although we’ve all seen dealerships’ attempts at prepping new cars!) and therefore assume that it needs little in the way of correction.

    Working logically through the process, the first stage to resolve is the washing and drying process: this tends to be where most damage occurs. Our guide to safe washing and drying is here – Safe Washing & Drying.

    I recommend using our Advanced Wash Kit as this includes a full set of wheel brushes, a non-acidic wheel cleaner and a great multi-purpose cleaner in addition to the basics, i.e. wash mitts, a drying towel and a bottle of shampoo. Whilst I’m conscious of keeping costs down, in the long term this will probably prove to be a wise investment. Obviously, two clear wash buckets will be vital too.

    If the car does require a little correction you will be able to achieve good results working by hand, because Mitsubishi’s typically have soft paint. For areas which need correction, I recommend using Menzerna 203S with a Lake Country Light Cut Hand Pad.

    Our step by step guide to polishing by hand can be found on this page – What Does Polishing Do?. I recommend using Poorboy’s Super Thick and Plush Towels for buffing off the polish residue. By following the guide and using these products, the rate of paint removal will be minimal, but the results should be spot on.

    After correction (if required) maximising paint protection is crucial. With metallic black, you have some options: a sealant will give a more reflective look, maximising the metallic flake in the paint, whilst a wax will offer a deeper, wetter look at the expense of the metallic flake.

    Working to a lower budget, 3M Performance Finish gives good results at a lower price point. This should be applied with a Meguiar’s Foam Applicator Pad in accordance with the instructions under the ‘How To Use tab’ on the product description page.

    In terms of waxes, you might like to consider Poorboys Natty’s Blue Paste Wax (designed for dark colours) or, if you don’t mind regular re-applications, R222 Concours Look Carnauba Wax, which gives a great finish at the expense of durability.

    The waxes should be applied in accordance with their respective ‘How To Use’ guides, again using a Meguiar’s Foam Applicator Pad. Both waxes and the sealant mentioned above should be buffed off using a Poorboy’s Deluxe Mega Towel.

    I hope the above information helps. Obviously there may be other products you may wish to use from the outset (wheel sealant, tyre dressing, glass cleaner, etc) but I am aware of your limited budget so have left them out for now. Of course, if you require any further specific advice and can’t find the answers on the product description pages or within our car care guides, please let me know and I will do my best to help.

    Best regards,


  8. Rank says:

    Hi John,

    Great blog!

    I am new to detailing and about 3 weeks ago detailed my wife’s car…2006 VW Golf GTI…Tornado Red…being a daily driver.

    I used the Megs G220V2 with LC pads and the following products:
    Menzerna SIP, Menzerna Final Finish and LSP was Collinite 915 wax…I washed with Megs Gold Class and clayed with Adams kit.

    The car came out really great but I feel I can do a better job…I have learnt new techniques after reading and gained more knowledge

    Can I do the car again with the same products? Is it too soon? Will it damage the paint?
    What steps should I do?


  9. Hi,

    Ideally, I think yes, it’s a little too soon to polish the car again: we recommend machine polishing your car no more than once every 12 months. It would be useful to know what you feel can be improved in your car’s finish. It is most likely that improvements can be made to your machine polishing technique to further enhance the paint finish – this is key prior to applying a last step product.

    Additionally, whilst it offers excellent durability and protection, Collinite 915 isn’t exactly the greatest wax in terms of aesthetics and it may be that this is another aspect where improvements in your car’s appearance can be made. A high carnauba content wax may give meaningful gains; I’d look at something like Raceglaze Signature Series 55 or any of the waxes in the Swissvax range.

    My own car is Tornado Red so I know how good this paint can look when it’s prepared fully. If you’d like specific advice, feel free to email me at our usual address.



  10. Ashley says:

    Hi John,

    I’m new to detailing although I have always taken a pride in keeping my cars looking their best with autoglym products.

    After discovering your website and spending many hrs reading with interest posts regarding both the removal of contaminents after washing, polishing both by hand and machine and the various polishes available I would appreciate any advice you could give me regarding where to start with a three year old Audi Quattro Avant I have recently purchased.

    The car is in a light grey metalic and although in quite good condition I feel the paintwork could look shinier. Im aware that the shine on light metalics is never as deep as on darker base colours and metalics but would love to bring back that showroom finish. I have noticed that there is a sticker on the windscreen which suggests Autoglym Life shine, I can only assume that was carried out from new.

    I do have an electric polisher available which i purchased from my local body shop supplier all be it im very wary of using it after reading the warnings regarding thining of top coats.

    Help regarding the processes to be carried out and the products required would be a gfreat help.

    Thanks in anticipation


  11. Hi Ashley,

    I don’t have experience with Autoglym products so can’t really comment on how effective they are. However, we test and use every product we sell in the store, so I’m sure we can help you find the finish you’re looking for.

    Assuming you have completed the washing and decontamination stages (if you require any further advice with these please let me know), I’ll start with the polishing process.

    Audi paint is very hard and correcting it requires careful selection of suitable pads and polishes as well as the use of an appropriate technique. What type of polishing machine you have access to (i.e. dual action or rotary)?

    If you’re not an experienced user, I recommend using a dual action polishing machine, as the risk of removing too much paint is vastly reduced compared to using a rotary style machine (which are essentially professional tools).

    Given your needs, I recommend our DAS-6 Power Plus Hard Paint Polishing Kit. This kit contains all the pads, polishes and accessories you require to correct the paint on your car and also further enhance the paint finish: the finishing polish and soft pad should allow you to produce a very high gloss, pin-sharp finish.

    The DAS-6 Power Plus machine has a much more powerful motor than the standard Kestrel DAS-6 machine, and this will be of particular benefit on the harder paint (the standard machine is capable of correcting hard paints, but it is a much slower process). You may find our guide to polishing, and the illustrated step by step guide to machine polishing, useful: What does polishing do?

    After polishing, you can then look to protection and maximising the aesthetic of your car’s paint. Generally, a synthetic sealant will give a superior finish on silver, producing a sharper and more reflective look. I would personally recommend the Werkstat Acrylic Kit.

    This system will give a very sharp finish with a lovely slick feel to the paint. This will encourage dirt and water to sheet off the car, and it has great durability. As is the case for all of the products on our site, full usage instructions are provided on the product description page.

    Of course, if you require any further specific advice and can’t find the answers on the product description pages or within our car care guides, please let me know and I will do my best to help.



  12. Matthew Smith says:

    Hi John, great blog and fantastic website!

    I was wondering whether you could recommend a compound/polish combination that I can use with my DAS 6?

    I currently only have some Megs Ultimate Compound and some Dodo Lime Prime, along with Dodo Orange and Red foam pads, but neither seems to shift the very fine swirls that remain on the black roof of my dark silver Cooper S. I have been considering Megs 105/205, but wondered if another product would be superior. I’m not sure if I really need a more aggressive product, or if I just need to be more patient!

    I’m planning to follow the prep with a Werkstat Acrylic Kit, which based on your recommendations should suit my paint colour really well. Have you tried adding the Blackfire Glaze after the Prime Acrylic for extra jetting/gloss on darker paint?

    Many thanks for your help.


  13. Hi Matt, thanks for your enquiry. As you’ve suggested, the Meguiar’s 105 and 205 combination will be ideal for BMW paint. I’ve no experience with the pads you have, but I recommend using a Menzerna Polishing Pad with 105 for a higher level of correction, and a Menzerna Finishing Pad with 205 to refine. It would be good to double check your methods against our guide to machine polishing – What does polishing do? BMW paint is very hard so it can take some time to gain correction but using the Menzerna pads and Meguiar’s polishes will give you excellent results.

    After correction, I would use the Werkstat Acrylic kit alone, without adding a layer of Blackfire Gloss Enhancing Polish. Werkstat Prime Acrylic is a highly effective paint cleaner, and has higher cleaning capabilities than Blackfire Gloss Enhancing Polish. As you’re correcting the car via machine, there should be no need for a glazing product to fill marks – these should be removed through polishing. Apply one coat of Prime Acrylic to the surfaces then add as many layers of Acrylic Jett Trigger as possible. The two products are designed to work together, increasing durability and maximising gloss. Perform a final wipe down of the surface with Acrylic Glos to remove any smears.

    If you’d like to double check your methods, or if I can offer any further advice, don’t hesitate to get in touch. Regards, John.

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