April 24th, 2019
Automotive polishing is essential for perfecting and maintaining a vehicle’s paintwork, but it is not carried out in isolation. Severe flaws may require sanding prior to the application of an abrasive polishing compound to re-finish fresh paintwork that has run or been cured incorrectly. Organic matter must also be washed off and surfaces thoroughly dried before polishing to remove stains and chromatic variations. Automotive polishing may also require several steps and multiple polishing compounds to achieve the optimal surface finish from paintwork exhibiting multiple embedded flaws.
In this blog post, Saint-Gobain Surface Conditioning explores some of the most common steps of automotive polishing in more detail:
First Step: Sanding or Washing
Regardless of the application area or defect severity, the first step in automotive polishing is the removal of flaws and organic matter that abrasive compounds are incapable of tackling. Newly fabricated vehicles may exhibit a range of visual flaws that have propagated through the manufacturing chain. Poor paint opacity or industrial matter embedded in the surface of clearcoat may require sanding with a fine-grit sandpaper to ensure that optical variations do not proliferate to the end-product.
Similarly, the daily driver can accumulate numerous visual flaws due to environmental pollutants. Before these can be corrected using an automotive polishing compound, organic particles must be removed from the surface and the paint must be thoroughly dried using a microfibre cloth or chamois leather.
Second Step: First Stage Cutting
The first step determines the level of automotive polishing compound required to achieve the highest possible finish in the shortest possible timeframe. In automotive body shops and industrial production lines, this is a matter of both quality and cost.
Sanding is an aggressive method of paint correction that reduces more severe flaws by leveling the macro surface, while typically leaving sanding marks that need smoothing out with an abrasive compound. A high cut polish is applied to the polishing pad of a rotary buffer which is passed over bodywork panels with low to moderate pressure applied. The abrasive particles within the polishing slurry cut away at the clearcoat to level the uppermost surface and reduce optical variations. Once again, however, this aggressive action will reduce larger defects while creating finer flaws like holograms and swirls.
This second step may comprise multiple passes depending on the severity of sanding flaws.
Third Step: Finishing Up
Removing these finer flaws requires a finer abrasive particle to achieve the ultimate surface finish. Smaller crystallites are less aggressive and are tuned to remove small scratches, swirls, and holograms for a flawless finish.
For general maintenance of the daily driver, it may be possible to skip the intermediate stage and go straight from washing to the finishing step. New abrasive compounds have attempted to similarly streamline the automotive polishing process for body shop and production line applications, by providing novel abrasive particles capable of morphing from a high-cutting action to an improved finish. The focus on commercially-viable single-step automotive polishing directly inspired Saint-Gobain’s IDEAL range of alumina (Al2O3) abrasives and our unique IDEAL Super product.
Automotive Polishing Particles from Saint-Gobain Surface Conditioning
Saint-Gobain’s IDEAL Super product is an alumina powder centered around a particle size distribution of 5 microns. This undergoes a morphing action during application, offering an incrementally reduced cut to provide a rapid high gloss finish for any automotive application.