EXPERT KNOWLEDGE POLISHING PASTES

Polishing pastes are abrasive agents that are used for finishing work on metal surfaces, especially cutting tools. Their main task is to produce a smooth, shiny surface and to remove the fine irregularities and burrs that occur after grinding. They are used on leather strops, strops or polishing wheels and are essential to ensure the sharpness and longevity of blades.

How polishing pastes work

Abrasive pastes polishing pastes contain abrasive particles whose size and composition determine the fineness of the polishing process. These abrasive particles remove microscopic irregularities from the metal surface, smooth out grinding and polishing marks from previous processing steps and remove the so-called burr that occurs during grinding. Coarse-grained polishing pastes are suitable for pre-polishing and removing grinding marks and burrs, while fine-grained pastes are used for the final fine sanding and polishing to a high gloss. A well-polished cutting edge reduces friction when cutting and increases the cutting performance of the tool.

Polishing pastes consist of two main components:

1. Abrasive particles: These are the key ingredient and consist of abrasive particles such as aluminium, silicon carbide or diamonds. They vary in size and shape, which influences the grinding and polishing properties.
2. Binder: These components hold the abrasive particles together and ensure that the paste has a homogeneous consistency. Binders can be water-based or oil-based.

Use of polishing pastes

Polishing pastes are mainly used for sharpening razors, kitchen knives, scissors and other cutting tools. However, they are also used in jewellery manufacturing, metalworking and in the automotive and aviation industries, where surfaces need to be extremely smooth and free from scratches.

Metals polished to a mirror finish are more resistant to corrosion, as moisture, dirt and other corrosive substances roll off more easily. The smooth structure thus prevents pollutants from penetrating into tiny cavities, protecting the surface from rust and corrosion for longer. The polish smoothes out microscopic irregularities and scratches in the Material. This reflects the light evenly and gives the surface a mirror-like shine. Depending on the fineness of the polishing pastes used, stainless steel, for example, can be polished from a matt finish to a high-gloss, mirror-like surface.

Accessories for polishing with polishing pastes:

• Polishing disc made of Felt, cotton or Leather or Leather strops (push-on belt): The Polishing disc is mounted on a Bench grinders or a polishing machine and serves as a carrier medium for the Polishing pastes. Leather strops are a proven alternative to the disc.
• Safety goggles and gloves if necessary: working with rotating tools requires safety precautions.
• Cleaning cloth: to remove paste residues after polishing.

When polishing on the Polishing wheels, first apply a Polishing pastes lightly to the rotating disc. Hold the blade securely while placing it against the disc at a slight angle. Move the blade continuously to avoid overheating and do not hold the blade directly in the direction of rotation to prevent catching. For the finish, you can switch to a finer polishing pastes and continue polishing the blade with little pressure until it shines. This requires a second disc to match the grit of the paste. After polishing, simply wipe off the residue with a soft scarves or remove it under running water with a little washing-up liquid.

When polishing with a Leather strops or butt strap, a polishing paste can be applied to the Leather in small quantities. Lay the blade flat on the Leather and pull it backwards so that the cutting edge trails behind without cutting the Leather. Make sure to maintain the same Angle as when sharpening and make several even strokes. Repeat the process on both sides of the blade until the burr is removed and the cutting edge is mirror-smooth. Finally, wipe the blade to remove any polish residue.

The Polishing disc is particularly suitable for a gloss finish, while the Leather strops add the finishing touch to a knife or remove the burr.

Quality and selection of polishing pastes

The quality of a polishing paste depends primarily on the size and uniformity of the abrasive particles. High-quality polishing pastes are characterised by a precise grit, where the particles have a uniform size, resulting in a uniform and effective polishing effect. Cheaper products often contain uneven particles, which can produce unpredictable results and even scratches.

Diamond polishing pastes, which contain particularly fine abrasive particles made from synthetic diamonds, are considered to be particularly effective and long-lasting, as diamond is one of the hardest materials.

Polishing pastes are indispensable tools for fine work on metal surfaces. They smooth and polish the cutting edges and ensure an optimal, shiny result. Choosing the right polishing pastes, based on the fineness of the abrasive particles and the area of application, is crucial to achieving the best results. High-quality polishing pastes not only provide an effective polish, but also contribute to the longevity and performance of cutting tools.