Mostly German cars
Read DetailingWorld forums and see which ones they bitch about being hard to detail because of rock solid paint. VAG cars, proper super cars have hard thick paint quite often. Jap cars are mostly crappy for paint, but you just learn to live with it. Problem these days is they can apply the paint so thin and its water based, just doesnt make for durable finishes. Ironically, in all this "save the planet" BS and using less paint and water based, you actually do more damange as people like Chips Away have to fix it with oil based paints, and as its applied by hand, use more
As we alluded to in our guide entitled 'What does polishing do?', paint hardness varies significantly between different makes of car, and also in some cases between different ages of the same make and model of car. In the former case this reflects a market structure in which just three major paint manufacturers (BASF, Dupont and PPG) offering significantly different ranges of paint products are continually competing for OEM supply contracts with major car manufacturers. In the latter case this reflects industry wide changes brought about by either legislation concerning what can and cannot be used in automotive paints or technological advances concerning the properties of automotive paints. In recent years, the switch from solvent-based to water-based paints on vehicle production lines and the uptake of ceramic nano-particle clearcoat technologies are good examples of this. A further compounding factor to the understanding of paint hardness occurs in cases where vehicles have been partially or wholly resprayed, as bodyshops use entirely different paint systems to those originally applied in the factory, and these have significantly different properties. What all of this means for car care enthusiasts wanting to polish their paint is that due thought and consideration should be given to choosing a polish and pad combination best suited to the task in hand, as paint hardness does vary considerably from car to car and, in some cases, from panel to panel! This being the case, the key questions remain; how do you determine how hard paint is, and what polish and polishing pad should you be using?
As is often the case in industries where a degree of secrecy exists with regard to OEM supply contracts, there is no reliable data source available that identifies which paint types are used on which factory production lines; this applies to the past and the present day, and will probably be the case in the future too. However, even if such technical data were freely available, it would in all probability be meaningless to car care enthusiasts, as it would probably not identify paint hardness per se as a characteristic, or report on commercial polish suitability. Thus, the answers to both questions posed above can only really be provided by real world hands-on experience of polishing many different paint types using many different commercially available polishes and polishing pads. Indeed, this is exactly how we have acquired our own in-depth knowledge of paint types and how best to polish them, and we are happy to share our experience so that enthusiasts may benefit and achieve excellent results safely and effectively without wasting time or risking paint damage through trial and error. Accordingly, what follows below is a brief overview of our knowledge concerning typical paint hardness on UK specification cars, along with a reference table in the form of a pdf look up table that will enable you to quickly look up how hard the original paint on your car is likely to be. Once you have determined how hard your paint is likely to be, the rest of the questions in this guide will then help you to choose the polish and pad combination best suited to the task in hand.
Paint hardness (or more properly clearcoat hardness in the case of most modern paint systems) can be readily divided into three categories; soft, intermediate and hard. Soft paint is usually found on Japanese cars, some Italian cars, and, more recently, on most Vauxhall models (especially the VXR range). Light to moderate sub-surface defects in soft paint are typically quite easy to correct by hand or machine in a single step using either a high quality medium abrasive polish or a high quality light abrasive polish respectively, but care must always be taken to limit the paint removal rate, as total paint thickness is usually relatively low (typical range 70-100 microns), particularly on the leading edges of major panels. Soft paint is also highly susceptible to micromarring, which is the technical term for fresh sub-surface defects inflicted during the polishing process as unbroken down abrasive particles are continually moved around at the interface between the pad and the paint, leaving a faint pattern of very tightly defined swirl marks. Severe micromarring can be difficult to correct, and for this reason we recommend that soft paint is only ever polished using products containing fragile abrasives with light to moderate cut levels that breakdown easily, along with thermally reticulated polishing pads in order to limit the overall level of cut.
Paints of intermediate hardness are most common on UK specification cars and typically require a single stage machine polishing process involving a high quality medium abrasive polish if light to moderate defects are to be fully corrected. Total paint thickness on intermediate paint types is usually greater (typical range 90-120 microns) than on cars featuring soft paint, meaning that greater rates of paint removal can be safely tolerated if required. When working on paints of intermediate hardness, the risk of causing micromarring is usually lower, due to the greater surface resistance of the paint encouraging full and proper breakdown of abrasive particles during the polishing process. In general, we recommend that paints of intermediate hardness are polished by machine using products containing robust abrasives with light to moderate cut levels that breakdown relatively easily, along with firmer types of thermally reticulated foam polishing pads in order to provide a small amount of mechanical cut. As a general rule of thumb, most resprayed paint that is chemically cured and baked in a bodyshop booth at 60°C will also be intermediate in terms of hardness, and should be polished in the same way.
Hard paint is usually found exclusively on German cars and tends to be quite difficult to correct, even if the sub-surface defects present are relatively light. In recent years, the uptake of ceramic nano-particle clearcoat technologies by many German car manufacturers has resulted in the paint on these cars becoming even harder and thus even more difficult to correct. Total paint thickness on hard paint types is usually greater (typical range 110-140 microns) than on cars featuring either intermediate or soft paint, meaning that greater rates of paint removal can be safely tolerated if required. In all cases, a two stage machine polishing process involving light compounding followed by a refining step with a high quality finishing polish will be required if light to moderate defects are to be fully corrected. We recommend that hard paints are polished using products containing robust abrasives with moderate to high cut levels that breakdown slowly, along with firm non-reticulated foam pads in order to maximise the amount of mechanical cut on offer. If defects persist, recourse can be made to using ultra-coarse compounds and harder pads offering even greater levels of cut, but care should be exercised as such products obviously increase the rate of paint removal and are more difficult to use.
