Today everyone has heard of the existence of sandblasting. This is a great way to finish various surfaces. Using this method, you can effectively degrease, clean, remove old coatings, prepare products for subsequent finishing work. Sandblasting equipment is used even for frosting glass. It is not necessary to have a stationary device. If you have a compressor, just buy a sandblasting gun and enjoy all the advantages of this processing method.
Application area
Let's start with the areas in which this equipment can be used. The most famous method is cleaning metal surfaces in car body repair. The technology is also good for preparing car wheels before painting. In stationary devices, high pressure is created, with the help of which a stream of sand knocks down the remains of varnish, soil, scale and corrosion products from the metal.
The metal, which was processed in this way, after going through a full cycle of work will last longer due to the fact that this method of cleaning is much better than any other. Small grains of sand at great speed crash into the surface being cleaned, discouraging rust, which is necessarily located in the pores of the metal or in cracks. Often this cannot be achieved in any other way.
A sandblasting gun may be needed not only by specialists in the field of auto repair. It should be in the arsenal of every car enthusiast and home master. In addition to the fact that with the help of such processing it is possible to clean old coatings and traces of rust, the surface after sandblasting will be smoother. There are no scratches that occur after cleaning with brushes, sandpaper. This facilitates the process of applying the base layer of soil and improves adhesion to the metal.
In addition to bodywork, sandblasting is widely used in other fields of activity. With the help of large apparatuses, ships and various elements are effectively cleaned at factories and industrial enterprises. In addition to metal, sandblasting allows you to clean other materials. This is wood, brick, concrete.
On wood and glass, you can get interesting effects and ornaments. Using a sandblasting mat glass, which will then be used as a decorative element.
Device
The sandblasting gun consists of several basic elements. This is a body and a pen. There is also a nozzle. A fitting is provided for connecting compressed air , and in some models it also has a valve for adjusting pressure.
The control sleeve is necessary to ensure the adjustment of the flow rate of abrasive materials. Union nuts or pins that secure the nozzle internally to the body of the instrument reduce the risk of leakage. There is also a threaded sleeve, which is needed to connect the container with the abrasive.
In addition to the external, there is also an internal nozzle for a sandblasting gun. It has an injection profile and a truncated cone shape. The diameter of the latter narrows as the air flows.
General principle of action
A sandblasting gun for the compressor is used for preliminary surface treatment. Today this equipment is mass-produced - it can be easily purchased in stores. But the choice must be approached as responsibly as possible. Budget devices cannot boast of quality, while professional devices have too high a price.
A sandblast gun works as follows. The device is based on a nozzle and a trigger hook. Compressed sand and air are fed through this nozzle by means of a compressor. The latter is fed through a hose connected to the gun to a special fitting. When you pull the trigger, air is supplied under high pressure to the nozzle. This is how most models of pneumatic equipment work.
Injection guns
The principle of injection is used here, when pressure drops are artificially created in the stream of compressed air supplied from the compressor through the gearbox. Due to this, the air flow rate and kinetic energy increase. Air is weighted with sand or other abrasive materials.
Such sandblasting guns will be more effective than sandblasting chambers. Cameras are bulky, awkward designs. In addition, these tools need special care. The injection gun is more compact. easy, and all care comes down to purging.
A nozzle is mounted on the body of the device, the size of which is selected in accordance with the pressure that develops the compressor. The choice of nozzle depends on the diameter of the internal injection hole.
A tank or a hose is connected to the handle. Since abrasive dust can enter the lungs of a person, it is recommended to work in compliance with safety precautions. Then the compressor is turned on and the pressure of the air flow is regulated with the help of a control sleeve.
The ratio of nozzle and performance and compressor
For nozzles with diameters of six and two millimeters, the compressor should provide a flow rate of 0.2-0.3 m 3 / min. If the nozzle on the sandblasting gun has a diameter of eight millimeters, and the inside hole has a diameter of three, then the air flow should be 0.6-0.6 m 3 / min. For 10 mm holes - 0.6-1.3 m 3 / min. For nozzles of 12 millimeters - 0.9-1.8 m 3 / min.
A lower flow rate corresponds to lower air pressure and the distance from the nozzle end to the surface.
Ejection principle
Another principle may be used. Abrasive material is ejected from it through the nozzle. If there is a sufficiently powerful compressor, characterized by a significant air flow (from 600 to 800 liters per minute), then the mixture can be pumped directly through the gun. The ejection sandblasting gun for the compressor works according to this principle. But they are not so widespread - it takes a lot of money to clean one unit of area.
Gun with tank
Work with such equipment is limited by the capacity of the tank. When the sand runs out, it should be refilled. These devices are perfect for working in relatively small areas. Also, the device will show itself well if the surface is flat.
Gun with hose
These sandblasting pneumatic guns are less mobile, but you can work longer. However, there are no restrictions on the complexity of the processed surface.
Two hoses are connected to the device. One of them serves to supply air from the compressor. Another delivers abrasive. These are more convenient and compact solutions - there is no bulky tank and it is better suited for processing hard-to-reach spots. A sandblasting gun with a hose is a great purchase for a garage.
Nozzle and its features
In many ways, the effectiveness of using these tools depends on the quality of the nozzles used. This is a very important structural element. They are made from ceramic materials or brass. The most important characteristics for this element are the type of hole, its diameter, length, and also the material.
The diameter of the nozzle is selected depending on the capabilities of the compressor. The performance of the installation depends on how much power the jet has or how much air can pass through the nozzle in one unit of time.
As for the power of the air stream, it is directly proportional to the volume of air passing through the nozzle in one unit of time. To increase power, you need to choose a hole with a large diameter.
So, if we consider that a nozzle with an opening of six millimeters is 100 percent power, then other nozzles are selected as follows. Eight millimeters - 157 percent, 9.5 - 220, 12.5 millimeters - 400.
The nozzle can be made with your own hands. But it is better to buy a standard factory product. The sizes offered in stores are from 6 to 12.5 millimeters.
The length is selected according to how dirty the surface to be cleaned is. For surfaces contaminated only a little, choose short nozzles with a length of seven to eight millimeters. If processing of more complex sections is required, then the length can be considerable - up to 230 millimeters. Short nozzles are used when working in hard-to-reach places.
Straight nozzle
A nozzle with a constant diameter over the entire length is capable of providing an exit of the abrasive at a speed of up to 320 kilometers per hour. In this case, the outlet pressure will be about six atmospheres.
Venturi nozzles
These products form a higher speed jet. So, the speed can reach up to 720 kilometers per hour. Such products can improve the quality of processing. It is important that the use of nozzles with a channel of this type does not require special abrasive materials and does not lead to increased air flow. Also, the feature of these nozzles is that they can’t be made by hand.
How to choose the right one?
All types of sandblasting guns will be effective only if the nozzles are selected correctly. For household tasks, cast iron and ceramic products are suitable. But they are not recommended for large-scale work. So, they quickly collapse, which leads to an increase in air consumption and abrasive material.
For professional sandblasting guns, more expensive solutions are recommended. They are mainly made from carborundum, tungsten carbide or boron. They are characterized by high durability, as well as versatility in terms of the choice of abrasive materials.
What to look for when choosing?
When choosing a sandblasting gun, it is important to consider not only the characteristics of the device, but also the capabilities of the compressor. An important parameter when choosing is the air flow. For normal operation with this kind of tool, the compressor capabilities should exceed this gun indicator by 20-30 percent.
The pressure of modern models, which are presented on the modern market, can range from three to ten atmospheres. If you need to perform work on the decorative design of various surfaces, it is recommended to stop the choice on low-power models. To process concrete, metal and other materials, you need to purchase models designed only for high pressure.
A lot depends on the design of the gun. It has already been noted above that there are pistols with a tank and models with a hose. The first are needed for processing small surface areas. The second one can process quite large areas, as well as hard-to-reach spots.
Model Overview
There are several models on the market. All of them differ in various characteristics and features. Compiled a small rating on reviews of sandblasting guns.
Abac 756062
This is the perfect tool. It is equipped with a tank that allows the gun to be more mobile.
The handle is quite comfortable and does not slip in the hand. Combined connections based on rapid and bayonet mounts greatly facilitate the work. The hook allows you to store the device in suspension.
Shneider SSP-Strahiflix
This device is one of the best for decorative processing. It is also equipped with an abrasive tank. This is a German quality, although the model is not professional, but rather household. The cost of this solution is very affordable and is approximately three thousand rubles.
SuperMistral ASTUROMEC SuperMistral 50300
This sandblasting gun with a dust collector is suitable for professionals. It will be indispensable in automobile workshops and in small industries. In the kit there are several nozzles.
So, we found out what a professional sandblasting gun is, how it works and how to choose it correctly.