What is a polishing agent, sponge, or wool? How are these materials used together?

What is a polishing agent, sponge, or wool? How are these materials used together? A polishing agent consists of abrasives combined with a medium, which can be water, oil, or alcohol-based substances. Different additives are added by various manufacturers to disperse the abrasive material within the medium. Finally, the polishing agent is paired with a polishing cloth to achieve the desired grinding and polishing effect. First, let’s understand the common types of abrasives, generally divided into two categories: superhard abrasives and regular abrasives. There are only two types of superhard abrasives—diamond and cubic boron nitride (CBN). Common regular abrasives include silicon carbide (also known as carborundum), aluminum oxide (also known as corundum), zirconium oxide, and silicon oxide. In polishing, certain acids or bases are often added to the medium to achieve a corrosion-polishing effect. For example, when polishing stone or stainless steel, a small amount of acid (such as hydrochloric acid) may be added to the polishing agent. When polishing ceramics or silicon carbide materials, an alkaline solution (such as potassium permanganate) might be used. Hydrogen peroxide and other process methods may also be added to the medium to soften and activate the surface of the workpiece, improving the polishing rate and enhancing the surface quality.

As a result, the selection of polishing cloth becomes extremely important. Different types of polishing cloths have varying resistance to acids and bases, as well as different porosity and water absorption rates, which allow them to hold abrasive particles of different sizes for optimal polishing efficiency. For example: For coarse polishing, it is suitable to choose polishing cloths made of foam materials with large pores, or slightly harder cloths, to achieve rapid material removal. For intermediate polishing, the main goal is to remove the marks left by the coarse polishing and create uniform, consistent polishing patterns on the workpiece’s surface. A woven material with a bit of hardness is appropriate to achieve the desired surface effect. For final fine polishing, the goal is to ensure no marks or even the slightest scratches, as any minor scratch could ruin the entire process. At this stage, a material with higher water or oil retention and a porous texture, such as long or short nap fabric, should be selected. This provides adequate lubrication, preventing the generation of heat during polishing, which could lead to dry polishing, abrasive particle clumping, and ultimately, the formation of undesirable micro-scratches.

Below is a summary of common abrasive types along with recommendations for pairing abrasives and polishing cloths: