When performing repair work in an apartment, it is simply impossible to do without sanding the walls and ceiling, on which a layer of putty was previously applied. After all, the alignment of the walls is an extremely responsible procedure, performed in several stages, one of which is grinding.
During the preparation of walls for coating after leveling with putty, it is important that the grinding is carried out quickly and efficiently with the exact removal of planes and corners, and in some cases even curved surfaces.
To make a choice, you need to clearly understand the purpose of each type of grinder. At first glance, the principle of operation of grinders is the same - grinding the surface of the material using abrasive equipment. In each specific task, one type of grinder will perform brilliantly, while the other will not give the expected result. For example, eccentric machines cannot process internal corners, while vibratory grinders can do it. We will analyze the types of grinders and determine the scope of each of them
In the process of carrying out these works, ordinary grinding bars, both home-made and factory-made, can be used. However, this method is associated with a significant investment of time and effort, which can be avoided by resorting to the use of grinders.
To ensure ease of use, as well as to increase the reliability of these devices, many of them are equipped with special dust collectors, into which fine dust from putty gets into. Also, for these purposes, a special construction vacuum cleaner is often used to connect to the machine.
Another feature of the grinding equipment is the ability to adjust the speed of its moving parts.
Most modern grinders are equipped with a dust removal system: a construction vacuum cleaner is connected through a special nozzle or a dust collection bag is included. This makes the work process cleaner, the tool itself is better controlled, and the consumption of abrasive equipment is reduced.
According to the type of power supply, the machines are divided into mains and battery. The advantages and disadvantages of cordless grinders are obvious - mobility and independence from the mains, but the operating time is limited by the battery charge.
Types of grinders
According to the principle of operation, such devices can be divided into two main types: pneumatic and electric.
The main advantage of pneumatic models is their light weight and relatively low cost. Such devices are very often used as a professional tool, because even with prolonged work with them, hands do not get tired and labor productivity does not decrease. These positive qualities are explained very simply - pneumatic devices do not have motors. Their working mechanism is set in motion under the pressure of compressed air supplied through a hose from a special compressor.
The main disadvantage of pneumatic grinders is the presence of a bulky compressor. In other words, such a tool can only work in a workshop where it is possible to supply compressed air. That is why devices of this type are mainly used in car services and are rarely used for repair work. If such equipment is used to carry out repairs in your own apartment, you will have to additionally purchase an expensive compressor.
As for electric models, their main advantage can be called high mobility. The ability to connect to the mains is almost always there, and using an extension cord is absolutely no problem.The disadvantages of a power tool include its relatively large weight and overall dimensions, as well as its high cost.
If the grinder is chosen for repair work in a house or apartment and will not be used in the future at large construction sites, then the choice in favor of electric models is obvious.
According to the method of impact on the treated surface, grinders can be divided into the following groups:
- Tape.
- Vibrating.
- Eccentric (orbital).
Let's take a closer look at each of these types of grinders.
Belt sanders
For belt grinders, the tooling, the abrasive tape glued in the form of an endless ring, moves in one direction along two end rollers, one leading, the second rotates freely. Linear grinding and high abrasive speeds provide high productivity, but at the same time require increased control over the grinding process. LSHM weigh up to 7 kg, and the power of the electric motor varies from 500 to 1500 watts.
The three main standards for belt sanders are distinguished by the length of the sanding belt: 457 mm, 533 mm, 610 mm.
This tool is usually used for processing large areas. Such a grinder uses an abrasive belt for work, stretched over special rollers, during the rotation of which there is a constant unidirectional movement of the belt. Belt models have the highest performance compared to their counterparts, but they are not suitable for final grinding.
Application
Belt sanders are suitable for coarse sanding of surfaces made of wood, metal, plastic, mineral building materials. Often used when removing old paint or varnish, leveling putty. Due to the high performance, a large amount of material is quickly removed, and in combination with a coarse grit abrasive, a belt sander can perform the function of an electric planer. The quality of grinding is not the best indicator of this tool; shells and scratches often appear during processing. Effective when grinding glued panels and processing convex-shaped parts. There are models with the ability to work upside down, stationary.
With the help of a belt grinder, you can easily remove a layer of material of several millimeters, make an edge or rounding on the workpiece, remove old paintwork or rust. She is subject to: wood, metal, polymers, mineral building materials ... Clean the floors from paint - yes, correct the planed timber - please, align the putty wall with marriage - no problem. However, it should be understood that high performance is not the best friend of quality, there will definitely be scratches and shells. For finishing grinding, it will be necessary to use an orbital or surface grinder.
When choosing a belt type grinder, you should pay attention to the following functions of the purchased device:
- Automatic tape centering. With the help of special rollers, it is held exactly along the axis of movement. This feature prevents the tape from slipping, so its presence significantly increases the usability of this tool.
- Pipe for connecting a vacuum cleaner. Almost all modern models of grinders are equipped with a similar product, but this does not negate its importance in preventing the appearance of a large amount of dust from putty in the room where repairs are being carried out.
- Additional rollers included in the design of the grinder make it possible to eliminate the appearance of so-called dead zones when grinding close to the walls.
- It's no secret that the performance of an electric tool is directly proportional to the power consumption of its motor - the higher it is, the more we can squeeze out of a particular unit.In the case of LSHM, the consumer has the opportunity to choose from models with an engine from 0.5 to 1.2 kW
- The next important characteristic for a belt grinder is speed. A fast machine will do more, but it will not be possible to crush it if the outstanding speed is not backed up by additional power. The notorious torque is to blame, which says that the more speed a tool has, the less power it has left. The belt speed in these grinders can be in the range of 150–550 meters per minute. There may be a question, why even release smart, but relatively weak LSM? It's just that a super-productive (fast and at the same time strong) car is more difficult to control, it is heavier, larger, more expensive. With it, with excessive pressure, it is easy to spoil the workpiece. In turn, maneuverable high-speed lightweights are convenient in a short time, often "in place", to process a large area surface. If you still don't know what loads await the grinder - choose a slower model that can be pressed a little, so it will be more versatile.
- The kit may include a stand or special clamps designed for stationary mounting of the tool (very convenient for processing small parts). The grinding frame serves as a kind of limiter, which helps to avoid damage to the workpiece.
- Special attention should be paid to the dimensions of the working plane - the sole, respectively, to the length and width of the tape. Wide soles (100 mm) are characteristic of powerful professional models, making them more stable and productive. The hobby class is usually limited to 75 millimeters. The long and wide sole of expensive LSHM has a complex structure, consisting of a substrate and an elastic plate, which allows you to have a constant uniform contact of the emery with the part, such a tool “keeps the plane” well.
Belt sanders on Aliexpress, now there are fast delivery from two days and there are unique offers at a price of 2,100 rubles.
Application
This tool is not suitable for delicate grinding and requires special control when working. It can leave indentations in the material and, due to the nature of the sole, belt sanders do not sand well in corners. High noise level and frequent clogging of the dust outlet are the disadvantages of this tool.
Do not forget about sanding belts, I found from 150 rubles for 3 pieces.
Electric file
There are belt grinders for special purposes, the so-called belt files or electric files. Often used for cleaning welds and grinding materials in hard-to-reach places.
Only certain accessories are suitable for electric files, with a width of 9 to 30 mm.
Such belt grinders weigh much lighter than usual - 1-2 kg.
Surface grinding or vibration models
This is perhaps the most common type of grinding tool. Its most typical representative is a surface grinder. It is a device equipped with a rectangular sole, on which, with the help of special clamps, a sheet of sandpaper with the necessary grain size is attached. For different types of putty, different brands of sandpaper are used.
Another type of such instrument is delta grinder. According to the principle of operation, it is no different from the devices of the previous type, however, it has a triangular working sole (iron), which can become indispensable when working in hard-to-reach places (for example, when grinding corners). We will talk about them in more detail a little later.
Principle of operation: the sole makes reciprocating movements along the annular orbit, due to this, grinding or polishing is carried out.The power of the electric motor of this tool is from 150 to 600 watts.
The most important indicator of PSHM is the amplitude of the sole. In different models, it may vary, although it is invariably a relatively small value. On average, in the class, the platform moves by 1–3 mm; in more mobile models, figures of 5–6 mm may appear. A large amplitude helps to grind the surface faster, but such processing will also be rougher.
Another nuance is sole stroke frequency. At high speed, the machine quickly removes a relatively thicker layer, and at a lower frequency, it is easier to achieve a precise finish sanding. Some manufacturers make the frequency of the movement of the platform changeable, exceeding 20,000 strokes per minute, which allows you to adapt to the processing of various types of materials, to the characteristics of specific surfaces.
The sole comes in two types: standard - 100 X 200 mm, and mini - miniature options with a base of about 100 X 100 mm. Budget cars are equipped with a platform made of steel or high-strength plastic, and more expensive analogues - cast platforms made of alloys containing aluminum or magnesium. Good outsole is well balanced, which is easily determined by the low degree of vibration during no-load operation (idling). It is important what is the cover made of, the most suitable option is a porous polymer, it “holds” the plane better than rubber.
Here the choice is simple: mini surface grinders are suitable for tight spaces, they are lighter and more manoeuvrable than standard ones.
Application
Designed for delicate processing of large flat surfaces. They occupy an intermediate place in terms of the purity of the processing of parts between tape and eccentric. With the help of a surface grinder, finishing grinding of various surfaces is carried out: wood, plastic, stone.
Advantages: the ability to grind and polish internal corners, the availability of consumables and the moderate cost of the grinder itself.
Flaws: high noise relative to orbital ones.
Delta orbital sanders
A feature of this tool is a compact lightweight body - the weight of the tool is up to 1 kg; the sanding sole is delta-shaped, because of which these machines are called "iron". Motor power up to 300 W.
Grinding in hard-to-reach places is carried out due to the fact that the triangular sole makes quick vibrations with a small amplitude. Equipment (sanding sheets) for this tool is not sold everywhere and is more expensive than paper-based sanding belts or grinding wheels.
Application
With the help of a delta-shaped grinder, fine grinding of protrusions, blind corners, edges, profiles, cleaning of the adhesive that has come out, processing of objects with small details and complex surfaces is carried out.
Particularly good in carpentry, furniture making, stairs, automotive body work, used as a main tool and in addition to eccentric or orbital sanders.
Eccentric models
In everyday life, these grinders often referred to as orbital. They got this name because of the peculiarities of the movement of a round working sole, which simultaneously rotates around its axis and moves in an orbit with a small radius.
The sole rotates in orbit and simultaneously scrolls around its axis. Such a complex movement of the abrasive allows efficient grinding with a minimum of imperfections. Sandpaper is attached to such a tool with Velcro.
Random orbital sanders are considered the most efficient and versatile tool for polishing and grinding surfaces.In industrial production and in private use, they show the best result in terms of surface finish.
The machine weighing from 1 to 3 kg is equipped with a round sole with Velcro, to which an abrasive wheel on a felt basis is attached. Soles come in two sizes - diameter: 125 and 150 mm. Sanders with 125mm soles are lighter, designed for smaller footprints and for more delicate work than sanders with 150mm soles. Electric motors consume between 200 and 900 watts - more power means more performance.
Orbital machines also have differences in translational speed. If we talk about rotation, then this figure can be from 4 to 14 thousand revolutions of the eccentric per minute for models with adjustment, and about 12,000 for models without it. If we talk about the concept of "fluctuation" - then these figures will be half as much. In fact, everything is simple here, the higher the speed, the rougher the processing will be, but the faster the work can be done.
The eccentric of orbital machines may not have the same "span" - from 2 to 7 mm. This is called the amplitude of the oscillation. The smaller it is, the less vibration the device generates, the more compact the plate goes, the smaller the area we process, but the cleaner the grinding will be. In some ESHM, the operator can set a certain amplitude, affecting the performance and fineness of grinding.
When installing equipment, it is important that the holes on the sole of the grinder coincide with the holes of the abrasive wheel, otherwise the dust removal process will be difficult.
Application
They are used for coarse or delicate grinding on large surfaces, for interlayer processing of materials and coatings, for polishing, processing large surfaces along and across the fibers. Often machines of this type are used in carpentry and car painters. With the help of ESHM volumetric, profile and curved surfaces are processed. When working with an eccentric sander, it is unlikely to spoil the workpiece: make mashes, burn the material, or overdo it with the depth of grinding. Noise and vibration levels are lower than other types of grinders.
Sander for putty, walls and ceilings
There are special representatives of the grinding tool, which are designed to work with large areas on walls and ceilings, grinding plaster and putty. A feature of such models is the presence of a convenient telescopic handle and gearbox, as well as the ability to install large diameter grinding wheels on them (usually 215 or 225 mm). Wall and ceiling grinders can be used not only to smooth putty surfaces, but also to remove old paintwork, as well as to grind stone or concrete walls. The use of such a tool will significantly reduce the time and labor required for grinding work.
DEKO hand grinder
Trusted construction equipment manufacturer DEKO (1,400,000 Ali Express followers) has released a great workhorse grinder. 2 models - with and without illumination. Productive, lightweight, with built-in dust extraction.
Specifications:
- Power - 900 watts.
- Speed control from 1400 to 2700 rpm.
- 360 degree illumination. Shows defects that need to be sanded.
- No dust! Integrated dust extraction with collection bag. Work clean!
- Ease of abrasive replacement.
- Ideal for sanding walls and corners. Light weight and large working area!
Delivery from 3 days. 1,260 orders. 625 positive reviews, including from professionals.
Suitable for grinding: plasters, putties, polymer coatings, paints, decorative plasters.
Consider the main characteristics of grinding machines.
- One of the main characteristics of a power tool is power.Power ensures the productivity of the tool (in this case, the amount of material removed during the grinding process), the resource of the grinder and the duration of continuous operation also depend on the power. Thus, if you plan to carry out professional grinding of large areas, then it is better to opt for grinders with an electric motor power of more than 500 watts.
- The efficiency of work will also depend on the diameter of the grinding disc (sole), i.e. the larger the diameter of the working surface of the disk, the greater the area can be processed per unit of time. Most construction grinder discs have a diameter of 150 to 225 mm.
- Dust removal, or rather its efficiency, plays a very important role, because. directly affects performance. Dust extraction can be carried out forcibly with an industrial vacuum cleaner or in a special dust bag (usually supplied with the tool). Professionals recommend using a vacuum cleaner.
Sander with telescopic handle
Specifications:
- Power - 980 watts.
- Speed control from 500 to 2100 rpm.
- Length from 1.4 meters to 1.9 meters - comfortable work with ceilings!
- 360 degree illumination and optional flashlight. Shows defects that need to be sanded.
- No dust! Integrated dust extraction with collection bag. Work clean!
- Ease of abrasive replacement.
- Ideal for sanding walls, ceilings and corners. Light weight, telescopic handle and large working area!
Delivery from 3 days. Positive feedback, including from professionals.
Suitable for grinding: plasters, putties, polymer coatings, paints, decorative plasters.
Location of the electric motor
There are two options: the electric motor is located directly above the grinding disc and the option with the electric motor located remotely, i.e. on the handle. Accordingly, the disk drive (rotary movement) is transmitted either in a direct way (the electric motor is above the disk), or through a flexible shaft (the electric motor is located remotely). Both types of drive are quite reliable, but professionals often prefer direct drive. The layout of the grinder with an electric motor located above the grinding disc makes it possible to carry out more efficient dust removal due to vacuum. Some vacuum is created above the working surface of the disk due to the fan located above it. This ensures efficient dust extraction even without the use of a vacuum cleaner. Dust is collected in a special bag that can be hung on the operator's shoulder. The vacuum type of dust removal is not carried out on machines with a disc drive from a flexible shaft. Despite these advantages, grinders with an electric motor located above the grinding disc are heavier than grinders with a motor removed from the disc. This complicates the work, especially with the telescopic rod extended to the maximum (a type of machine with a variable handle length, see Handle type below). Although on some models the vacuum effect is so deep that it allows the grinder to literally stick to a vertical wall.
Handle type
An elongated grinder handle, often referred to as a "giraffe". The handle can be both fixed length and variable (telescopic). The extended handle of the grinder is convenient for processing surfaces remote from the operator, such as ceilings and high walls. The grinding head itself has a sufficient number of degrees of freedom for grinding at any angle necessary for the operator.
Which sanding gives the best surface quality?
There is an opinion that only manual grinding gives the best surface quality, grinding with a machine is not faster, and manual grinding is the fastest and highest quality.
This myth is nothing more than a myth. The flatness of the sole provides the necessary flatness. Adjusting the speed helps to choose the pace of grinding, and the use of abrasive material with a finer abrasive grain provides the necessary and sufficient level of surface quality with a significant increase in productivity. If we recall that, as a rule, in the old fashioned way for manual grinding, many use abrasive material of one grain - 100, then this conclusion is not surprising. Yes, you can use sandpaper with one grain, changing the pressure and frequency of movement to bring the surface to the ideal. You can also dig the whole field with a shovel ... But you and I do not need pure cheapness of work (although this is debatable with manual operations), but a significant increase in productivity while maintaining the specified quality and low costs per square meter. This is exactly what mechanized grinding systems provide (electric grinders in conjunction with dust removal equipment). It is also important to choose the right abrasive materials and, if necessary, it is possible and necessary to use abrasives of smaller grains: 180, 240, 320, 400.
But for assessing the quality of grinding, the hands are often more suitable than the eyes. It is not for nothing that women, who by nature have the best tactile sensitivity, work as controllers in the grinding shops.
If you are still used to working manually, then it is better to work at least with dust extraction. In this case, you need a set of polishing for all occasions: from small to large "planer".
How to grind putty correctly?
After applying the putty mass, it should be sanded. Depending on the type of putty applied, abrasive materials are also selected.
On coarse (fraction 0.5 mm - 2 mm) and abrasive material is needed more aggressively with a grain of 40 / 60 / 80 / 100 - it is selected individually due to the difference in the compositions and properties of putty from different manufacturers.
In the process of grinding the “finishing” putty, which has a fraction of not more than 0.1 mm, abrasive materials of a smaller grain size, up to 400, can be used.
Of course, the quality of the polished surface also depends on the quality of the putty itself in the first place. If your “finishing” putty has too coarse a fraction/grain (as a rule, these are cheap materials), then it will not be easy to achieve good quality with any grinding. And this is labor costs that neither you nor the Customer need. In addition, a poorly prepared mixture also causes a lot of trouble.
Therefore, professional Masters with extensive experience do not use cheap materials - it is more expensive for themselves.
By the way, a properly selected mixer with a suitable stirrer (corolla) provides better preparation of the mixture. And with tight deadlines and high customer requirements, it is more expedient to use liquid putties prepared by the manufacturers themselves with strict observance of the necessary requirements for the composition and properties of the mixture.
Do not forget about the quality of the puttying process itself: the cleaner the putty is applied, the less it needs to be sanded. As the old painter's rule says: “when puttying, leave less “snot”, you will not erase your hands to the elbows when grinding”.
Useful accessories and accessories
When processing large volumes, additional accessories and accessories will not be superfluous.
In particular, an additional extension (each manufacturer has its own), which increases the working height available for work from the standard 2.6 m to 3.5 m.
And the use of a support vest with a belt (like Festool) will increase the comfort of work and the productivity of processing ceiling surfaces. Scaffolds and stepladders will not be superfluous.
TIPS FROM MASTERS
Professional Masters with extensive experience usually have in their assortment: a large grinder with a 225 mm wheel, a small grinder with a 125-150 mm wheel and a couple of hand grinders. This set allows you to work as flexibly and productively as possible.
As for the construction vacuum cleaner, then it is better to buy a vacuum cleaner not back to back, as is often the case, but with a margin. Therefore, the most optimal vacuum cleaner with an actual volume of more than 30 liters. It is worth considering that many manufacturers indicate the effective volume, and not the actual one. The actual is equal to the effective minus the volume occupied by the filter.
So, which grinder should you choose?
It is necessary to quickly clean a large surface without special requirements for quality, to remove a large amount of material, choose a belt sander.
You need to constantly process small parts or grind various angles, choosing a delta grinder.
You need a universal tool for grinding a large number of different materials, choose a grinder.
If the tool must be universal, but there are high requirements for the quality of grinding We opt for an eccentric sander.
The choice of the required type of grinder for each case is carried out taking into account the volume and nature of the work performed, the configuration of the surfaces to be sanded, as well as the individual preferences of the person who will perform this work. In any case, the final result will be the main criterion for the correctness of the choice made.
Having decided on the task and type, we make a choice in favor of a specific model of the grinder.
If you have to work with the tool on weight, on outstretched arms, you need to pay attention to the dimensions and weight of the grinder. The choice is better to make in favor of a light, compact, faster machine, albeit less powerful. If the work will be mainly on the workbench, choose a machine with more weight, more powerful.
