Sandpaper – grit marking, production and use

Sandpaper (sandpaper or emery)
is an abrasive glued to a fabric or paper base. This paper is often used for grinding and grinding surfaces made of wood, metal, plastic, glass or ceramics. For several centuries it has been наждачная бумага маркировка зернистости изготовление и применение

an indispensable material for construction repairs and in the woodworking industry. The abrasive powder, which is the main component, has undergone changes with the development of technological processes. Sandpaper consists of sand and pumice, silicon carbide and diamond, firmly glued together with a special compound.

Sandpaper grit markings

Sandpaper

carry out dry and wet sanding of wood, metal, plaster and putty. The density of the coating is denoted by the word “granularity”, and the diameter of the granules by the words “grain size”. For various types of work and sanding wood, abrasive sandpaper with different degrees of grain size is used, which is indicated by special markings. If rough surface treatment is required, coarse-grained paper is used. For fine polishing, the finest grains are used.

Global grain size designation
is a unified standard for manufacturers producing products for export. In some countries of the former USSR, they are still marked according to GOST, adopted in Soviet times. The same thing happens in other countries of the world: in the domestic markets of countries such as China, Japan, USA
and Canada, have retained their sandpaper marking designations.
European marking
suggests an increase in values ​​with decreasing abrasive grain size. In the old Soviet GOST, on the contrary, there is a decrease in values ​​relative to a decrease in grain diameter. These nuances are taken into account when purchasing sandpaper in the territory of the former USSR, since confusion can lead to the purchase of bad material. The difference in designation probably only affects the everyday life of the average person who buys hides for use in construction and car repairs.

European marking ISO-6344 in accordance with Soviet GOST 3647-80

полная таблица соответствия маркировки зернистости наждачной бумаги по ГОСТуу и по стандарту ISO

  • Coarse-grit sandpaper is designed for rough work. In such cases, sandpaper with p grain size from 500 to 1000 microns is used.
    . According to the ISO standard, such paper has the following numbers: P36, P24, P22. They correspond to the following GOST values: 50-N, 63-N, 80-N. These are the largest grains used in the production of sandpaper.
  • For very fine grinding and polishing of the surface, use sandpaper with a grain size from 3 to 14 microns
    . These values ​​correspond to ISO numbers from P2500 to P1200. Accordingly, the values ​​​​of the Soviet GOST are from M5 to M14.
  • Medium-sized grains have a fairly wide range, they are marked with numbers ranging from very small to very large.

Marking by type of filling

The marking of sandpaper by type of filling is determined by the percentage coverage of the base with abrasive. With open and semi-open filling 40-60% of the base is filled

, with closed (solid) filling the surface is completely covered. In the first case, the skins are used for products made from soft wood and for molded plaster surfaces, and in the second – for metal and hardwood. It should be noted that the closed covering
gives it high grinding performance, which allows you to obtain the highest quality surface finish.

Manufacturing method and application

Sandpaper is available in rolls or cut into squares. The second option is suitable for use at home during repairs, for example, when sanding шлифование штукатурки на стенах с помощью наждачной бумаги

rough surface by hand. This option is also used in parquet sanding machines. To do this, cut rectangles measuring 240 by 720 mm

.

Waterproof sandpaper is usually resilient and is used for removing varnish, putty, and paint in the construction and automotive industries. To produce such skins, grains of silicon carbide are used.
, bonded with synthetic resin or electrolyte. This paper is a durable type of sandpaper with a high abrasive ability. For industry, it is made on a fabric basis and is characterized by high wear resistance.

Using sandpaper at home

Sandpaper is often used for household tasks. Here are some of them using sandpaper in the household.

  • Cleaning the seams between bath tiles
    . Darkened grout between tiles is difficult to clean with cleaning products. To do this, home craftsmen advise using a sheet of fine-grained sandpaper folded in half. But you should clean the grout with great care, trying not to damage the tile.
  • Sharpening needles with sandpaper.
    The use of sandpaper for needlewomen can be very wide, but most often it is sharpening needles and knitting needles. To properly sharpen a sewing needle, you need to pierce the sandpaper with it several times or “wrap” the tip in the sandpaper and rotate it. It’s convenient to always have sandpaper at hand.
  • Updating the cutting board.
    Kitchen wooden cutting boards become cut by a knife over time. This not only spoils the appearance of the board, but also impairs the hygiene of food preparation. In all these grooves and depressions there are pieces of food that attract bacteria and microbes. To level a wooden cutting board, you need to sand it with sandpaper.
  • “Repair” of suede leather
    .
    Light abrasions and stains on suede clothing can be removed using sandpaper. It’s best to gently brush it over areas that need cleaning, and then use a clothes brush several times to get the lint back in place.

To understand what kind of sandpaper you need, watch a short video that explains how to choose sandpaper and for what purposes to use different grain sizes of such abrasive paper.