Sandpaper processing. Sandpaper: varieties, application, marking

Sandpaper is an abrasive material applied to a fabric or paper base and is an indispensable tool for a wide range of home craftsman's work.

Let's look at the symbols with which the manufacturer informs us about the types of sanding paper and the permissible areas for its application.

Sandpaper grit

This parameter of abrasive paper reflects the number and size of abrasive particles per unit area, is the main characteristic of sandpaper and determines the possibility of its use for certain needs.

What is the difficulty?

Today in stores you can find sanding paper marked both according to Russian GOST and the standards of other countries.

The confusion is that domestic marking on the skin can be done in a new way. GOST from 2005(focused on European standards) and according to GOST 80s years approved by the Ministry of Machine Tool and Tool Industry the USSR.

The two categories of standards are reversed. AT old GOST 3647-80 a decrease in marking numbers indicated a decrease in grain size. AT new GOST the grain of the abrasive decreases, and the number in the marking, on the contrary, grows.

In addition, there is no unity among global manufacturers. The USA and Canada, Europe and Turkey, Japan, China adhere to their own standard.

Grit, purpose and marking table

GOST R 52381-2005 (Russia)	GOST 3647-80 (USSR)	Grain size (µm)	Purpose
Coarse-grained
P22	80-H	800-1000	Roughing
P24	63-H	630-800
P36	50-H	500-630
P40	40-H	400-500	Rough woodwork
P46	32-H	315-400
P60	25-H	250-315
P80	20-H	200-250	Primary grinding Surface Smoothing Removing small bumps
P90	16-H	160-200
P100	12-H	125-160
P120	10-H	100-125
P150	8-H	80-100	Preparing hardwoods for sanding Final sanding of soft woods Grinding old paint for painting
P180	6-H	63-80
Fine-grained
P240	5-H, M63	50-63	Final sanding of hardwoods Sanding between coats
P280	4-N,M50	40-50
P400	М40/Н-3	28-40	Polishing of final coatings Sanding before painting Wet sanding
P600	M28/H-2	20-28
P1000	M20/H-1	14-20	Grinding metal, plastics, ceramics Wet sanding
P1200	M14	10-14	Even finer grinding, polishing Removal of gloss, stains, micro-scratches
P1500	М10/Н-0	7-10
P2000	M7/H-01	5-7
P2500	M5/H-00	3-5

Russian marking. GOST old and new (ISO)

New GOST

The letter is always listed first. "R". The number after indicates graininess.

For example: P400- this is a well-known "null".

Old GOST

The first is a number indicating the size of the abrasive. The following are the indexes: P means that the amount of the main fraction of the abrasive grain is not less than 55% , index H- at least 45% , index D- at least 41% .

8-P means that the number of abrasive granules that pass through a sieve with a cell side 80 µm. at least 55% .

To designate microgrinding powders in the old GOST letter comes first M. The number behind it is the grain size in µm.

For example, the same "zero": M40

This is how the reverse side of the sandpaper that I bought just yesterday looks like:

(Posted a picture below. new marking)

Areas of application of abrasive skins according to the type of grit.

1. Sandpaper with coarse grain (coarse-grained - macrogrid)

The roughest work. Removal of burrs, rust. (corn 1000 µm - 500 µm)

New GOST: P22, P24, P30, P36 P22- largest grain ( 1000 µm), P36- the fewest ( 500 µm))

Old GOST: 80-P, 63-P, 50-P (hereinafter in decreasing order of grain, i.e. 80 - largest grain ( 1000 µm), 50 - the fewest ( 500 µm))

Rough woodwork. Pre-sanding various surfaces (500 - 250 µm)

New GOST: P40, P46, P54, P60

Old GOST: 40-P, 32-P, 25-P

Removing a layer of varnish, paint or drying oil. Elimination of uneven plaster. intermediate grinding ( 250 - 100 µm)

New GOST: P70, P80, P90, P100

Old GOST: 20-P, 16-P, 12-P, 10-P

Final sanding. ( 50 - 105 µm)

New GOST: P120, P150, P180, P220

Old GOST: 20-P, 16-P, 12-P, 10-P

2. Sandpaper with fine grain (fine-grained - microgrid)

fine grinding ( 60 - 40 µm)

New GOST: P240, P280, P320, P360

Old GOST: 5-P, 4-P.

Polishing, "wet" grinding (using cutting fluids). ( 40-20 µm)

New GOST: P400, P500, P600, P800

Old GOST: M40, M28, M20

Grinding metal, plastic, ceramics. Finishing processing of any kind of wood, leather goods. (20-14 µm)

New GOST: P1000, P1200

Old GOST: M20

Superfine grinding, polishing of corrosion-resistant steels, production of microsections. ( 14-3 microns)

New GOST: P1500, P2000, P2500

Old GOST: M14, M10, M7, M5

It is also useful to understand what types of sandpaper are divided into in addition to the size of the abrasive grain and how this affects its functionality and cost.

Abrasive material

I was not too lazy to photograph the inside of the skin of which birdhouse processed.

Line resin bonded- abrasive material, grinding material (according to the English - Russian dictionary of mechanical engineering and production automation)

If you look at reverse side your sandpaper, you will most likely see a similar plain inscription aluminum oxide what does alumina mean? in the common people electrocorundum). Such an option as silicon carbide or ceramic abrasive is possible.

The first is a brittle material and is used for processing wood, alloy steel, and cast iron.

Second ( silicon carbide) has a high hardness and is designed to work with glass, plastic, metal.

As a rule, this knowledge is enough for a wide consumer for housework, but we general development We propose to cover the topic more widely:

Areas of application of skins in accordance with the type of abrasive material

Aluminum oxide normal(93-96% Al 2 O 3 - for example 16A) such skins are intended for ductile iron, hardened and non-hardened steels, wood.

Aluminum oxide white(Al 2 O 3 not more than 99% - for example 25A) - for processing heat-resistant and alloyed steels.

Silicon carbide(for example 64C) - finishing of metal, cast iron, bronze, aluminum, plastic, marble, granite, glass, wood.

Flint(for example 81K) - for processing wood, plywood, leather.

Glass(for example 71C) - for processing wood, plywood, felt, felt.

Garnet- for processing hard hardwoods (oak, beech, etc.).

Elbor- for polishing precision surfaces, hard-to-cut steel parts.

Diamond- for polishing and fine honing of precision parts made of hard alloy and cast iron.

Sandpaper base type

1. paper-based sandpaper

Such sandpaper has a rather low wear resistance coefficient. Along with a low margin of safety, paper-based emery usually does not have waterproof properties.

P1, P2, PZ... before PI- waterproof paper.

This greatly narrows the scope, but also reduces the market value.

2. cloth-based sandpaper

Today, the most common fabric bases are cotton and polyester. Fabric-backed abrasives are most often water-resistant due to their special impregnation resin based.

L1, L2 and M- wet-strength paper.

Such emery has a higher margin of safety compared to paper.

In the marking with the first digit, the manufacturer may indicate 1 or 2 .

1 - the skin is intended for materials of low hardness (fillers, primers, paints, enamels, soft woods, plastics)

2 - for hard metal alloys.

There is also sandpaper on a mixed basis (cloth + paper) or other materials (for example, fiber-based discs are widespread).

Type of abrasive application

1. sandpaper with a semi-open or open abrasive coating

The base is half closed. The gaps between the particles cover 40 to 60% base area. Such an abrasive is used for processing soft and loose materials.

In the course of work, lumps are not formed, due to this, clogging of empty spaces with waste is excluded.

2. sandpaper with a closed or continuous abrasive coating

It is characterized by full coverage of the base with grinding material and is designed to work on hard surfaces.

Full decoding of sandpaper markings

So, we already understand something and can try to read what the manufacturer meant.

For example, such a label ( old GOST)

Example: 2 830x50 S2G 24A 40-NMA GOST 5009-82.

Abrasive for processing hard metal alloys ( 2 ), in roll ( 830 mm at 50 m) on a fabric basis - twill ( S2G), from electrocorundum ( 24A), with a grain size of 40 µm ( 40-N), on skin glue ( M).

Explanation

binder type: M- skin glue; FROM- synthetic resin; To- combined link.

In the old GOST, the sixth letter indicated the abrasive class - the number of defects. AND no more 0,5% ; B- no more 2% ; AT- no more 3% .

Therefore, the number of defects ( AND) on the working surface of our example, no more than 0,5% .

or (new European standard on the example of German sandpaper VSM)

Example: KK X P150

Aluminum oxide abrasive ( K) on the fabric ( To) and rigid ( X) basis with granularity P150(75-106 µm).

Used for grinding, polishing and cleaning surfaces. For manual processing, choose sheet or roll paper (you can cut a piece from it right size). For machine - finished goods from sandpaper: sanding belts, circles and strips with Velcro. In this review, we will describe in detail what types of sandpaper and its graininess are.

Types of sandpaper

The main characteristic of sandpaper is graininess, i.e. the number of abrasive grains per square inch of surface. At low grain size, the particle size is relatively large. Coarse-grained paper is used at the beginning of processing. It allows you to roughly sand and clean the surface, remove the remnants of old paint. After it, scratches remain, so further grinding with finer sandpaper is necessary.

As the grain size increases, the grain size decreases. Such a skin is called fine-grained. It is used for fine, meticulous work, in particular before painting. A simple example - you decide to repaint the closet. You will need 2 types of sandpaper for wood, differing in grit. First large (P60), then medium (P100). Ideally, it is better to go through a third, smaller sandpaper (P150).

The second most important parameter is the type of basis. There are two main types of paper:

• With paper backing. It is normal and waterproof. Of the advantages - it is cheaper, does not stretch during work. It is possible to apply the smallest grain. Of the minuses - less resistant to wear.
• With fabric base. It costs more than paper, but it has high tensile strength and is more resistant to moisture. Due to its elasticity, it can stretch in length. The stiffer the base, the more durable the tape will be.

Sandpaper Grain Chart

Depending on the grain size of the paper, there are two marking standards: Russian (with the letters H and M) and international (with the Latin P). Below you will find a marking correspondence table. Types of paper with large and medium grain size are marked in blue, paper types with fine grain size are marked in yellow. The proposed type of work is also indicated.

Sanding paper is most in demand when working with wood material. Since wood has a rough surface, craftsmen almost always use just such a thing as emery to remove it. What is it? Sandpaper or sandpaper is the main purpose of which is to give perfect smoothness to almost any surface.

Paper backed emery

Quite a bit of. However, only a few of them are the most popular. The most used were emery on a paper or fabric basis.

If we talk about the paper basis of this thing, then it is most often characterized by a rather high density material. This is a very important parameter, since it will determine which mechanical damage can handle the paper. In order to increase the service life and range of use, sanding paper can sometimes be made with a waterproof backing.

The advantages of this type of material:

• low cost of the material, especially when compared with additional grinding nozzles that are sold on a drill;
• using this type of sandpaper, you don’t have to worry that the base will elongate in the process;
• the surface of paper-backed sanding papers can be coated with the least abrasive during production.

However, there are also disadvantages, which include poor wear resistance, as well as low strength inherent in paper.

Fabric base

For the production of sanding paper with such a backing, cotton is most often used, which is pre-treated with a special resin. It is because of this method of production that fabric emery is characterized by increased resistance to water, improved flexibility, and is also characterized by a rather high strength.

The disadvantages of such a grinding skin include the fact that cotton tends to lengthen during operation. The second disadvantage is the higher cost compared to other bases, since cotton itself is more expensive, in addition, a special resin is also needed for production.

It is worth adding that combined sanding skins are currently sold in specialized stores. Such emery is based on paper and fabric materials glued together.

Types of emery according to the method of applying grain

Sandpaper differs from each other not only in the base, but also in the type of grinding grain that was used in the creation.

1. The first type is paper that has an open filling. During the production of this type of paper, the grain is sprayed in such a way as to cover up to 60% of the entire area of ​​​​the skin. The advantages of this class include the fact that during operation it will not be clogged with debris due to the presence of large gaps between the grains of the abrasive. Most often, this type of emery is used for processing wood coatings or surfaces with an average density.
2. The second type is a closed filling. This type of paper assumes that the entire base of the skin is covered with a dense layer of grain during production. Using this grade of sandpaper is great for hard surfaces, but it needs to be handled with care as it clogs very quickly.

Abrasive grain for sandpaper

To date, different abrasive grains are used to produce such paper or drill bits. On this basis, 4 different types material:

• Ceramic abrasive. This type of abrasive is one of the hardest, and therefore it is used for rough processing of wood material. It is produced in the form of special tapes.
• Silicon carbide. This type of grain is characterized by low strength indicators, as well as medium wear resistance. The scope of this material is grinding body metal, fiberglass, etc.
• Alumina. This type belongs to the very fragile, as it breaks very quickly under mechanical stress. However, this drawback can also serve as an advantage, since in the event of a breakdown, new edges will form for grinding, which means that emery can be used much longer.
• Garnet. Most often, paper with such an abrasive element is used for processing different breeds tree. This type of abrasive is considered one of the softest, and therefore its wear resistance is very low. In order to work with it, you need to have a lot of patience, since the process of grinding with such paper is very laborious.

Sanding paper marking

The designation of the abrasive skin is regulated by GOST. In this document, the main parameter is indicated by the grit, which is denoted by the letter P, and the limits of this parameter are numbers from 12 to 2500. It is important to understand that the larger the specified number, the smaller size grain on paper. It is also worth noting that in some former Soviet republics GOST USSR is used. In this case, the number 20-N will be indicated on the marking. In this case, it is important to know that tens of microns of grinding are indicated. If you need to specify a simple number of microns, then the marking will look something like this: M20. An approximate classification of the types of sanding skins looks like this:

• for the most rough processing of the material, emery type P22, P24, P36 80-N, 63-N, 50-N is used;
• for simply rough surface treatment, grinding with the marking P40, P46, P60 40-H, 32-H, 25-H is used;
• in order to carry out the primary grinding of the desired surface, paper grade 20-N, 16-N, 12-N, 10-N is used;
• in order to complete the grinding of the material and give it perfect smoothness, it is necessary to use sandpaper brand P150, P180 8-H, 6-H.

Sanding paper size

The size of the sandpaper is determined depending on its grain size. Emery with a grain index of 50 has a width of 720, 750, 800, 850, 900, 1000. This indicator is measured in millimeters. Paper with such parameters of width and grain size is produced in rolls 30 meters long. It is worth noting that with P50 and a width of 1250 mm, the length of the roll is reduced to 20 meters. For sanding paper, GOST 6456-82 defines all standard sizes, production and acceptance rules.

Production

The production technology of this product consists in the method of applying the abrasive to the base. There are several methods for performing this operation. It could be mechanical way application or a variant using an electric field. Each manufacturer of sanding paper chooses which method to apply the abrasive. It is also worth noting that an important factor during production, the choice of connecting elements will also act. They may be of different brands or types. Also, the strength and mode of operation of the abrasive skin will depend on the type of bond.

Sanding is one of basic techniques work with a wide range of materials. Processing, be it manual or machine, is carried out with abrasive skins. We will tell you about the numerous varieties of sandpaper and the principles of its choice in today's review.

Grits and numbers - how to determine grit

Grain, aka roughness, is a key parameter for any type of sandpaper. Grit is always indicated on the reverse side of the sandpaper after the letter P or the word Grit, sometimes both designations are used at once. Grain is defined by a number from 12 to 15000, sometimes even more.

In the simplest representation, this figure is the number of abrasive particles per square inch, if they are scattered in a continuous uniform layer. In reality, this number is determined by the number of wires per square inch of the sieve through which the abrasive was sieved. The actual particle size ranges from visible to the naked eye (1-1.5 mm) to completely microscopic (whole and tenths of a micron).

Let's define the scope of sandpaper depending on the grain size:

• up to P80 - for rough peeling and grinding in order to level the surface;
• from P100 to P220 - used in the second stage of grinding, if you need to eliminate small grooves and scratches;
• up to P280 - used for fine grinding;
• smaller skins are already classified as polishing.

You can read more about the exact choice of sandpaper for various purposes.

The rule for choosing sandpaper by grain size is very simple - the higher it is, the smoother the surface will be after processing. But at the same time, the finer the sandpaper, the faster it grinds, and the removed layer of material becomes smaller. It should also be taken into account that the greater the hardness of the material being processed, the coarser the paper can be used for finishing. At the same time, on soft wood, even with a grit in P220, quite visible scratches can remain.

Skins by type of base

Even in a small town, walking through hardware stores, you can find several dozen different samples of sandpaper. They will differ not only in grain size, but also in the method of applying the abrasive material, the type of coating and binder, as well as the abrasive material used or a mixture thereof. However, in practice, the type of substrate on which the abrasive is applied is of paramount importance.

The cheapest and most quickly consumed emery cloth is made on a paper basis. It has few advantages: in addition to the low price, the paper is convenient if you need to quickly tear off a fresh shred for work. The abrasive from such a skin crumbles quite quickly, especially in places of fracture, however, the paper base makes it easier to process relief surfaces.

The cloth-based skin has slightly more high cost but much more durable. In many households, half a dozen scraps of cloth sandpaper can be found lying around, which are successfully used from time to time for several years and have not lost their abrasive qualities. It does not do without drawbacks: the fabric impregnated with epoxy is rough, the treated surface is felt worse under it. Also, cloth sanding belts tend to stretch, although this mainly applies to consumables for machining.

Finally, there is a third type of sanding paper - soft-backed. This includes foam or polyurethane skin, used for finishing embossed wood and plaster parts, and fiber sanding paper. The latter, although it has similar properties as a pressure to the part, is used for fastening to the working body with Velcro, for example, to rotary grinders.

Dry and wet sanding

Depending on the abrasive material and its binder, sandpaper may differ in the admissibility of grinding with surface wetting. In addition to the fact that wet sanding paper is more expensive than normal paper, there are a number of other reasons why this distinction is important.

When removing particles from the treated surface, the friction forces at certain points can be so high that the generated temperature is sufficient to sinter the metal dust. This, in particular, is true for aluminum and most non-ferrous metals: if the skin is not periodically shaken off, it will quickly become clogged and become unusable.

In some varieties of paper, this problem is solved by a special abrasive material. So, silicon carbide, especially applied by electrostatics, is able to crumble, forming new cutting edges, so this paper practically does not clog. However, there can be a lot of particles of removed material, for example, when processing plastic, and then it is necessary to prevent them from sticking together by moistening the sandpaper with water.

Polishing natural stone, marble or concrete also can not do without the use of water or special formulations. Wetting improves the quality of grinding and prevents the spread of stone dust

Wetting resistance is determined by the standard, which is indicated at the end of the marking on the back. Paper according to GOST 13344-79 allows work in a humid environment, but according to GOST 6456-82 it does not. There are exceptions, because water resistance is generally determined by the type of binder, that is, glue. Although the type of binder is usually not specified, processing wet method abrasives bonded with synthetic substances are suitable: bituminous, polyester resins, phenolic varnishes, etc. Very often, the possibility of using paper for wet work is additionally indicated by the letter "B" or the word Waterproof.

For manual processing

Often a home craftsman has to process their products manually. So the quality of grinding is much higher, there are fewer untreated areas. For manual processing, paper is available in sheets, strips and rolls.

The running types of grit in the economy are tissue paper P60, P80 and P120. Smaller skins usually have a paper base. It is recommended to always keep in stock different numbers of abrasive paper for fine grinding up to P400.

Cloth-based skins above P300 grit are produced mainly for machine processing, although they can be worked with alternate success by hand. The main difficulty is that the abrasive is filled with a solid layer of binder, and manual processing of such a tape is extremely slow, especially at high grain sizes. However, wet grinding with such paper is a pleasure.

Also, for manual processing, polyurethane grinding sponges will be very useful, which are very convenient for processing parts with small relief. If you are fond of woodworking, always have a supply of foam rubber skins, this is the most effective remedy for preparation for painting or varnishing.

Belts and discs for machine grinding

When buying consumables for grinders, it is difficult to make a mistake. All of them have a specific type and working dimensions - either length and width, or dimensional number, or diameter.

For belt sanders and grinders, cloth-based paper rolled into a ring is used. The length and width in millimeters is the main parameter of such sandpaper, which determines suitability for use with a particular tool.

If you can still "play" with the width, using more narrow tape or by tearing off the excess, then random length bands can only be used on grinders with adjustable tension. Also note that only one direction of movement is valid for the ring belt, indicated by the arrow on the back.

With abrasive paper for rotary and delta sanders, it's even easier. They either fit the size or they don't - the size of suitable consumables is clearly indicated in the instructions for the equipment. When choosing, you should also pay attention to the position of the dust extraction holes. Since we are talking about a power tool, almost all sandpaper in consumables is designed for dry grinding. It remains only to choose the right grain size according to the type of material and the desired surface quality, and then gradually reduce it during processing.

6. The validity period was extended until 01/01/93 by Decree of the USSR State Standard of 04/23/87 N 1374

7. REPUBLICATION (April 1990) with Amendments No. 1, 2, 3 approved in June 1984, April 1987, July 1989 (IUS 9-84, 8-87, 11-89)


This standard applies to paper abrasive paper intended for abrasive processing. various materials without cooling or with the use of cutting fluids based on oil, kerosene, white spirit.

1. TYPES AND DIMENSIONS

1. TYPES AND DIMENSIONS

1.1. Grinding skin should be made of types:

1 - for machine and manual processing of non-metallic materials (wood, leather, rubber, plastic, etc.);

2 - for machine and manual processing of metals, alloys.

1.2. Grinding skin should be produced in rolls, the dimensions of which are indicated in Table 1.

Table 1

Grain	Width, mm (limit deviation ±3.0)	Length, m (limit deviation ±0.5)
	720; 750; 800; 850; 900; 1000
	1250; 1350; 1400
	720; 750; 800; 850; 900
	1250; 1350; 1400
	720; 750; 800; 850; 900

Note. At the request of the consumer, it is allowed to manufacture rolls with a length of more than 100 m.

1.3. Sanding paper should be made with the following types of working layer:

C - solid;

R - embossed.

1.4. The designs and dimensions of the relief working layer must correspond to those indicated in the drawing and in Table 2.

table 2

Dimensions, mm

Grain	Width,
	Interval	Previous off	Interval	Previous off

The angle of inclination of the relief should be 5°-85°.

1.5. The deviation from parallelism of the generatric lines of the relief must be within the tolerance per step of the relief.

An example of a symbol for paper abrasive paper type 1, with a continuous working layer C, 1000 mm wide, 50 m long, on paper grade 0-200, from normal electrocorundum grade 15A, grain size 25-H, on skin glue:

1C 1000X

50 P2 15A 25-N M GOST 6456-82

2. TECHNICAL REQUIREMENTS

2.1. Sandpaper shall be manufactured in accordance with the requirements of this standard.

2.2. Grinding skin should be made from grinding materials listed in Table 3.

Table 3

Type of abrasive	Grade of sanding material
Normal electrocorundum	15A; 14A; F14A; 13A; F13A
White electrocorundum	25A; 24A; 23A
Alloyed electrocorundum	94A; 93A; 92A; 91A; 91A-M and 92A-M
Zirconium electrocorundum
monocorundum
Green silicon carbide
Black silicon carbide	54C; 53C; 51C
Glass

Note. At the request of the consumer, it is allowed to manufacture abrasive skins from other grades of abrasive materials or their mixtures.

2.3. For the manufacture of sandpaper, paper according to GOST 18277-72, GOST 10127-75 and industry regulatory and technical documentation for paper in accordance with Table 4 should be used as the basis.

Table 4

Paper grade	Symbol

Note. If the paper does not have an established symbol, it is allowed in symbol sandpaper indicate its brand.


(Changed edition, Rev. N 2).

2.4. Grinding skin should be made from grinding materials with grain sizes indicated in Table 5.

Table 5

Paper convention	Grain
	electrocorundum grinding materials	monocorundum	silicon carbide
P2; P3; P4; P5; P7; P8; P9; P10; P11

Note. At the request of the consumer, it is allowed to manufacture sandpaper of other grain sizes or their mixtures.


(Changed edition, Rev. N 3).

2.5. The abrasive material must be connected to the base with skin glue in accordance with GOST 3252-80 or other bonds according to industry normative and technical documentation.

Note. It is allowed to introduce dyes or coloring pigments into the bundle.

2.6. Grain composition of grinding materials - according to GOST 3647-80.

2.7. (Deleted, Rev. N 3).

2.7.1. On the working surface of the sanding paper with a continuous working layer, the total area of ​​wrinkles, folds, areas without abrasive grains, filled with a bundle, should not exceed 0.5% of the roll area.

Note. By agreement with the consumer, the total area of ​​these defects is allowed no more than 1% of the roll area.

2.7.2. On the working surface of the abrasive paper with a relief working layer, the total area of ​​defects (fusion and non-printing) of the relief layer per 1 m2 should not exceed 5% of the area of ​​the roll with the applied abrasive material.

(Changed edition, Rev. N 3).

2.7.3. In a roll of sanding paper with a width of up to 1250 mm, edges with a width of more than 10 mm with defects are not allowed, with a width of more than 1250 mm - more than 15 mm.

Note. On the working surface of silicon carbide and electrocorundum sanding paper with a grain size of 6-M40, dot adhesive formations or inclusions protruding above the working surface are not allowed.


(Changed edition, Rev. N 1, 2, 3).

2.8. The unevenness of the thickness of the sandpaper should correspond to the values ​​indicated in Table 6.

Table 6

Grain	Thickness unevenness, mm, no more

2.9. The tensile strength of the abrasive skin, depending on the grade of paper, must correspond to the values ​​\u200b\u200bspecified in Table 7.

Table 7

Paper convention
	longitudinal	transverse

2.10. The coefficient of application of the abrasive material on the base for abrasive paper with a relief working layer should be 0.40-0.75.

2.11. The moisture content of the sandpaper should be 3-7%.

2.12. The given wear of electrocorundum and glass abrasive skins must correspond to the values ​​indicated in Table 8.

Table 8

Grain	Reduced wear for types

Note. The reduced wear of silicon carbide sanding paper grits 6-M40 type 1 should be 1.5-7.0; type 2 - St. 7.0.


(Changed edition, Rev. N 2).

2.13. The cutting ability of the sandpaper under the test conditions specified in mandatory annex 2 must correspond to the values ​​\u200b\u200bspecified in table 8a.

Table 8a

Grain	Cutting ability of the skin, g/min, not less than
	electrocorundum	silicon carbide	glass

(Changed edition, Rev. N 2, 3).

3. ACCEPTANCE RULES

3.1. Acceptance inspection and periodic testing should be carried out to verify that the abrasive paper meets the requirements of this International Standard.

3.2. Acceptance control for compliance with the requirements of clauses 1.2, 2.7.1, 2.7.2 and 2.7.3 must be subjected to at least 1% of the rolls of sandpaper from the batch, but not less than 3 pieces, according to clause 1.4; 1.5; 2.12 and 2.13 - 0.1%, but not less than 3 pcs.

3.1, 3.2. (Changed edition, Rev. N 2).

3.2.1. The batch must consist of sandpaper of the same specification, made in one shift and simultaneously presented for acceptance according to one document.

3.3. If, during the acceptance control, non-compliance with the requirements of the standard for more than one controlled indicator is established, then the lot is not accepted.

(Changed edition, Rev. N 2).

3.3.1. If a non-compliance with the requirements of the standard is established for one of the controlled indicators, then a second control is carried out on a double number of skin rolls.

If there are defects in the resampling, the lot is not accepted.

(Introduced additionally, Rev. N 2).

3.4. Products (one of the sizes of rolls) that have passed the acceptance control (according to clause 3.2) must be subjected to periodic tests for compliance with the requirements of clauses 2.8 and 2.10 0.5%, but not less than 3 pcs., clauses 2.9 and 2.11 0.5 % rolls of sanding paper grit 40; 8; 5 and M40, but not less than 3 pieces, item 2.9 - on all types of bases.

(Changed edition, Rev. N 2).

3.5. Periodic tests should be carried out at least once a year.

(Changed edition, Rev. N 3).

4. CONTROL AND TEST METHODS

4.1-4.1.2. (Excluded, Rev. N 2).

4.2. The dimensions and external defects of the working surface of the abrasive skin are measured with a measuring metal ruler in accordance with GOST 427-75 or with a measuring metal tape measure in accordance with GOST 7502-89.

4.2.1. The angle of inclination of the relief is measured universal means measurements or special template.

4.3. The uneven thickness of the skin is measured with a micrometer of the MK type (with a tolerance limit of ±0.01 mm) at a distance of at least 10 mm from the edge of the roll.

(Changed edition, Rev. N 2).

4.4. The calculation of the coefficient of application of abrasive material on the base is given in the mandatory Appendix 1.

4.5. To determine the moisture content of the sandpaper, three samples with dimensions of 100x100 mm are taken, weighed on technical scales with a maximum error limit of ±0.01 g. The sandpaper samples are placed in an oven and dried at a temperature of (100±5) °C until between two successive weighings will not exceed 0.02 g.

The moisture content of the sandpaper is determined by the difference between the masses before and after drying and is calculated as a percentage of the original mass.

4.6. The reduced wear of the sandpaper (the ratio of the grit size of the sandpaper to its crumbling) is determined on the KZSH VNIIASH device by abrasion of the sandpaper on the sandpaper for 2 minutes at a load of 29.4 N.

Two samples of sandpaper with dimensions of 395x50 mm and 520x50 mm are subjected to the test.

Samples are weighed on technical scales with a margin of error of ±0.05 g.

Notes:

1. The crumbling of the abrasive skin is equal to the mass of the crumbled working layer in a given time interval under given conditions.

2. When calculating the reduced wear for grain sizes M63; M50 and M40 in the numerator are taken, respectively, the numbers 5; 4 and 3.


(Changed edition, Rev. N 2).

4.7. The method for determining the cutting ability of sandpaper is given in mandatory annex 2.

4.8. The determination of the tensile strength of the abrasive skin is carried out according to GOST 13525.1-79, except for paragraphs 3.1 and 4.1 at a temperature environment. The maximum deviations of the dimensions of the test specimens shall be ±1.0 mm.

(Changed edition, Rev. N 2).

4.9. Samples for control according to paragraphs 4.1-4.8 are taken from any place of the roll, remote from the end of the roll or edges by at least 10 mm. The value of the indicators according to paragraphs 4.3 and 4.5-4.8 is taken as the arithmetic mean of three determinations.

5. MARKING, PACKAGING, TRANSPORT AND STORAGE

5.1. On the non-working surface of the abrasive paper roll, every (235 ± 20) mm in the longitudinal and every (200 ± 20) mm in the transverse directions must be applied:


symbol (except for the type and indication of the type of the working layer);

batch number.

Notes:

1. When using a mixture of abrasive materials, mark the brand of the main grinding material in the symbol, when using a mixture of grit sizes, mark the main grit.

2. By agreement with the consumer, the dimensions of the roll may not be applied.


(Changed edition, Rev. N 2, 3).

5.2. Link markings:

skin glue - M;

combined ligament - K.

5.3. The winding of the sanding paper into rolls should be even and dense, with the working layer outward, preventing the formation of wrinkles, folds and crumpled places.

The end surface must be even, the protrusions of the edges of the roll with a width of up to 1250 mm should not exceed 5 mm, with a width of more than 1250 mm - 10 mm.

(Changed edition, Rev. N 3).

5.4. Each roll of sandpaper must be wrapped with a double layer of paper in accordance with GOST 18277-72, GOST 2228-81 or GOST 10127-75.

The roll must be sealed at the joint. Layers wrapping paper must cover the ends of the roll and ensure its safety during transportation.

5.5. (Deleted, Rev. N 3).

5.6. Each packaged roll must be labeled or stamped with the following data:

trademark of the manufacturer;

symbol;

release date and batch number;

technical control stamp;

image of the State Quality Mark according to NTD for sanding paper, which in in due course awarded the State Quality Mark.

5.7-5.16. (Excluded, Rev. N 3).

5.17. The remaining requirements for labeling and packaging, as well as transportation and storage, are in accordance with GOST 27595-88.

(Introduced additionally, Rev. N 3).

Section 6. (Deleted, Rev. N 2).

APPENDIX 1 (mandatory). CALCULATION OF THE COEFFICIENT OF APPLICATION OF GRINDING MATERIAL ON THE BASIS

APPENDIX 1
Mandatory

The ratio of the application of abrasive material to the base (- the ratio of the area of ​​​​the base with the applied abrasive material to its total area) for:

executions 1 and 3 is calculated by the formula

where is the relief width, mm;

Relief step, mm;

execution 2 is calculated by the formula

execution 4 is calculated by the formula

(Changed edition, Rev. N 1).

APPENDIX 2 (mandatory). METHOD FOR DETERMINING THE CUTTING ABILITY OF A GRINDING PAD

APPENDIX 2
Mandatory

1. The essence of the method

The method is based on the determination of the mass of organic glass ground by a sample of abrasive paper during the test.

2. Equipment and materials

2.1. Scheme and description of the device type MI-2 - according to GOST 426-77.

2.2. Grinding paper samples with an outer diameter of (174±5) mm and a hole diameter of (55±3) mm.

2.3. Plates made of organic glass brand TOSN - according to GOST 17622-72.

2.4. Rubber pads hardness 60-80 Shore.

2.5. Glue grades BF-2 and BF-4 in accordance with GOST 12172-74 or other grades that ensure the strength of the connection of organic glass plates with a rubber gasket - according to regulatory and technical documentation.

(Changed edition, Rev. N 2).

3. Preparation for the test

3.1. Stick the plates on the rubber pads.

3.2. New plexiglass plates are pre-lapped under test conditions until signs of wear appear on the entire working surface of the plates, cleaned of dust and weighed with an error limit of ± 0.01 g.

4. Testing

4.1. Set the test modes indicated in the table.

Grain	Clamping force, N	Processing time, min	The presence of blowing during processing
			Without airflow
			with airflow

(Changed edition, Rev. N 1, 2).

4.2. Mount the sanding pad to be tested, changing the sanding pad on the disc after lapping.

4.3. Fix the organic glass plates in the holders in the same position as when grinding.

4.4. At the end of the test, release the organic glass plates, clean them from dust and weigh them with a maximum error of ± 0.01 g.

5. Processing of test results

5.1. Cutting capacity (g/min) is determined by the formula

where is the mass of ground organic glass, g;

5 - processing time, min.



Electronic text of the document
prepared by Kodeks JSC and verified against:
official publication
Grinding cloth and paper skin.
Specifications: Sat. GOSTs. -
M.: Publishing house of standards, 1990