In colloquial speech, grinding paper is often called "nazhdachka" or "skins".
It consists of a paper or fabric base with a layer of abrasive material applied.
Ancient Chinese in the 13th century, using a sticky substance based on starch, glued to the parchment seeds of plants, finely chopped sand and shells.
The prototype of a grinding paper is "glass paper", because For its manufacture used the smallest particles of glass.
You should know that the granularity of sandpaper is one of its main characteristics.
Conditionally the paper was divided into groups: coarse-grained, medium-grained and paper with fine grain.
The size of the grains determines the type of work for which the sandpaper is intended . Marking will help her choose.
Emery works are carried out for dry and wet processing of all kinds of ground surfaces.
For different types of work , grains and sandpaper are used. The labeling of such paper is specific.
Granularity of the grinding skins
|Old GOST||New GOST|
Н - marking of domestic production (old).
Р - marking of imported products and new marking of domestic products.
Producers who produce products for export use a single world standard for the designation of grain size.
In some states of the collapsed Union, sandpaper, marking of finished products of emery works are carried out according to GOST (old).
The same thing happens in Canada, China, the US and Japan, where the domestic market uses its own designations.
The European standard (new GOST) implies an increase in values as the grain size decreases. Absolutely differently in the above-mentioned countries, sandpaper is marked.
GOST, for example, is designed in such a way that here the values, on the contrary, decrease as the grain size decreases.
These differences can not be ignored when buying abrasive products in the territory of the former Soviet Union, t. This difference can lead to the purchase of an unsuitable product.
Note that imported paper is most often sold in products, and domestic - in rolls, and sell it with running meters.
If paper is used in everyday life, it is not necessary to remember the labeling. You just need to know that the old marking comes with the letter H after the number, and the new one with the letter P in front of the figure.
There are other signs on the back of the paper. On them it is possible to establish additional information about a nest: its basis, production technology , type of abrasive, grain material, type of binder, etc.
Now you know what sandpaper is. Marking? With it you also figured out. It remains to wish everyone a pleasant and fruitful work.