Sandblasting gun for compressor

To clean a metal surface from varnish or paint, you can use special attachments for angle grinders. Appropriate hand tools are also used for such purposes. In addition to angle grinders and hand tools, metal surfaces can be cleaned with a sandblasting gun for a compressor. Let us find out in detail why it is worth using this tool and how effectively it copes with the assigned tasks.

What is a sandblasting gun and its purpose?

A sandblasting gun is a nozzle for a compressor, which is designed to clean car body surfaces from stubborn dirt and paintwork. The sandblasting attachment is popular in auto repair shops for painting cars, but nothing prevents a home craftsman from buying a gun for a compressor and using it to clean any metal surface, which is often done before painting, patination and anodizing.

Externally, the nozzle almost completely resembles a gun for blowing or painting a compressor, but there is still a difference. The main structural elements of the device are:

Metal body in the form of a pistol
Channel - hose for supplying abrasive substance to the gun
Nozzle - a hole through which sand flies out under pressure and hits the surface being treated.
Handle with trigger - designed to hold the tool body, as well as to start the sandblast feed
Adjustment screws for adjusting air pressure and abrasive feed rate

The most important element of the device is the nozzle, which must be made of high-strength materials such as tungsten or ceramics. If you choose sandblasting guns for a compressor with a nozzle made of plastic or thin metal, then such a tool will not last long. The nozzle will very quickly fail under the influence of abrasive substances.

The operating principle of a compressor sandblasting gun is that fine sand flies out of the nozzle under the pressure created by compressed air. This removes paintwork and other contaminants from metal surfaces.

This is interesting!
Sandblasting is intended not only for processing metal surfaces, but also for removing contaminants from plastic, wood and other materials.

How to choose the right model?

Before buying sandblasting machines, you need to familiarize yourself with a number of factors that affect the performance of the equipment:

Sandblasting devices must be equipped with thick-walled hoses to withstand prolonged exposure to abrasive and pressure.
The abrasive feed rate depends on the size of the hole on the nozzle.
It is not recommended to buy models with plastic parts, as they will quickly fail.
You need to evaluate the pen before purchasing so that it is convenient to work in the future.

If you need a model for your home, garage, or workshop, you need to buy a unit with a container for abrasive.

How does a sandblasting gun work?

If you decide to use a sandblasting gun for the first time, it will not hurt to first understand the question of its operating principle. Knowing the principle of operation of the nozzle, it will not be difficult to learn how to use it. First, let's find out how a sandblasting gun from a compressor works:

The gun is connected via a hose to the compressor through the receiving fitting
The air enters a special chamber where its pressure can be adjusted
The air is directed through the channel to the nozzle
Due to the passage of air through the channel, sand and abrasive are sucked from a special container (due to the pressure difference)
The amount of sand sucked in by air can also be adjusted with a special screw, which depends on the tool manufacturer
Not only compressed air is supplied through the nozzle, but also sand with abrasive particles, which have a cleansing effect on the surface

The operating principle of the tool is somewhat similar to the functioning of a spray gun. Often these two tools are used simultaneously when performing paintwork. Initially, the surface is cleaned and then painted. Moreover, this applies not only to car bodies, but also to various structures on the farm, for example, gates, fences, poles and others.

Operating principle of sandblasting machine

Sandblasting works according to an elementary system. If you compare the drawing of a simple sandblasting apparatus and basic models of a spray gun, you will notice a similarity in design. The pressurized air passes through the air ducts and entrains the material for abrasive processing. Small grains are sent to the surface at high speed, knocking out particles from it.

You can develop a homemade sandblasting machine, but creating a compressor will be very difficult. To create an installation of sufficient quality, it is recommended to buy a factory compressor with a capacity of 500 l/min. To avoid destruction from overheating, it must have a cooling system. Installation power from 3 kW.

Homemade sandblasting from a Kamaz receiver

Types of sandblasting guns for compressor

Today you can buy a nozzle for a sandblasting compressor quite inexpensively, which is due to the low quality of such a tool. However, for periodic use of such attachments in the household, they are quite sufficient. Professionals prefer to work with expensive sandblasting guns, which not only have high performance, but are also reliable.

Sandblasting equipment is divided into two types according to the principle of operation:

Pressure type - abrasive material is supplied from the reservoir through a hose to the nozzle of the gun, and flies out through the nozzle onto the surface to be treated. The principle of operation of the pressure system is based on the fact that compressed air is supplied into a sealed container with sand, which pushes the fine mixture through a special channel into the chamber. The finely dispersed consistency supplied under constant pressure is picked up by a stream of compressed air and transported to the nozzle, from where it flies to the surface. These types of equipment are classified as professional, and they are often used for processing ships, bridges, etc.
Ejector type (not to be confused with injection ones) - the operating principle is based on creating a pressure difference, from which the effect of suction of a finely dispersed consistency occurs. Sand and air are mixed in a special gun chamber and released through a nozzle

The operating principle of both devices is shown schematically in the photo above. The most popular are ejector-type devices, which are used not only by specialists in car services, but also by home craftsmen.

It is important to note that sandblasting guns differ in the type of location of the container with the abrasive substance.

With a tank - the container is a component of the gun, which makes the tool similar to a spray gun. Nozzles with a tank have one significant drawback - the need to frequently interrupt to fill the container with sand. That is why such devices are used exclusively for processing small-sized surfaces. These attachments are also used for engraving on glass and other structures.
With a hose - used when processing large surfaces. The material is supplied from a separate container, which can have different sizes, which is a great advantage, allowing work to continue until the sand is completely used up. Sand is supplied from the container to the gun using a special connecting hose. The nozzle without a tank for connecting the hose is similar to a conventional blow gun

Before choosing a sandblasting gun, you need to decide what size surfaces you plan to process. Often, tools with built-in capacity are enough for home use.

Homemade pistols

Craftsmen make such devices themselves at home. They are tank guns, and they use a 1-5 liter plastic bottle to store sand. The nozzle will have to be purchased ready-made, since you won’t be able to make it yourself. This part must be made of durable material, as it is exposed to sand and compressed air pressure. Additionally, it is worth buying a set of tips for the nozzle - even the highest quality ones will have to be changed regularly.

The sandblast body must match the size of the nozzle. Two hoses are attached to it, which should also be purchased: one goes to the bottle with sand, the second is connected to the compressor. Instead of the housing, you can use a water tee. The compressor for the gun must have a receiver, which will ensure a uniform supply of air at a stable pressure.

To process metal and concrete, you will need a powerful compressor; for wood, a device of medium or low power. Before putting the sand into the device, it must be washed, dried and sifted several times, otherwise the gun will quickly break.

Due to the moderate price of many models, before making your own, it is worth calculating the costs of components: it may be better to buy a ready-made device. In any case, the quality of processing of the products will be similar, so you will have to make the choice yourself.

What are the advantages and disadvantages of a sandblasting gun?

Each tool has not only advantages, but also disadvantages. The situation is similar with sandblasting nozzles for a compressor. Their advantages include:

Fast and effective processing of various types of surfaces - metal, plastic, wood, glass
Ability to access hard-to-reach places, which is often impossible to do manually or with power tools
The ability to independently manufacture nozzles. Many home craftsmen make sandblasting guns with their own hands from improvised materials.
Large selection of nozzles, differing in external design, as well as the name of the manufacturer
High productivity, which has a positive effect on saving time

With the advent of sandblasting guns for compressors, they have gained great popularity. However, if you are not familiar with this device, then do not rush to buy it until you know all the negative aspects:

The service life directly depends on the quality of the tool, and the higher this indicator, the correspondingly more expensive the nozzle will be. Cheap models have a short service life
Noisy operation
The need not only to use high-quality nozzles, but also to periodically replace them when worn out
Loss of abrasive material during operation

Another drawback that can be identified is the need for additional surface cleaning and sand removal. However, such manipulations must be performed after any type of processing.

Application of technology

A sandblasting gun is a device for carrying out abrasive processing of various materials, surfaces, and objects. As an independent device or in conjunction with a sandblasting chamber, it is used in construction and repair, metallurgy, instrument making, the automotive industry, and a number of other industries.

The device is in demand for different types of work:

removing rust before applying anti-corrosion compounds, other protective agents or to extend the service life of products;
grinding wood, metal, plastic, stone, ceramics (objects, blanks, individual components) before decorating;
cleaning from dirt and old paintwork;
frosting glass to give an opaque effect (dishes, showers, windows);
degreasing metal before coating with varnish or paint;

applying drawings to glass and other materials;
cleaning parts of complex shapes;
restoration of art objects;
imparting roughness to materials in order to enhance adhesion with various coatings;
artificial aging of wood - furniture, decor, interior elements;
cleaning the car body from dirt and old coatings before painting.

A sandblasting gun is indispensable for cleaning various curved parts: you can spend a lot of time on this process manually, and the quality of preparation of the product will not be the best. When using sandblasting, even hard-to-reach areas will become perfectly clean and sanded in a short period of time.

Sandblasting gun with recovery or how to do dust-free processing

Tool manufacturers are constantly improving their creations, which is exactly what happened with compressor attachments - sandblasting guns. The modernization of these devices is that they are additionally equipped with special dust collectors. Such nozzles are called sandblasting guns with abrasive recirculation. These devices with an abrasive recycling system allow sandblasting to be carried out without waste and with minimal sand loss.

Unlike conventional sandblasting nozzles, guns with abrasive recirculation are equipped with a nozzle made of rubber material. Such nozzles not only ensure a long service life, but also allow dust-free processing. The operating principle of a dust-free sandblasting gun with recirculation is as follows:

The sand released from the nozzle with air hits the surface to be treated, cleaning it
After this, the sand is not sprayed, but returns to the nozzle, but accumulates in a special bag
Once the bag is filled with sand, it can be reused

Loss of abrasive material does not exceed 5%, which is very convenient and economical. Closed cycle sandblasting nozzles are also produced based on the recuperation gun. A certain portion of sand is transported in a circle, performing useful work in the form of cleaning the surface. To use the nozzle for a sandblasting compressor with recovery, you should perform the following manipulations:

Place a nozzle of the appropriate shape on the gun - square, triangular, round, etc. It all depends on the shape of the area being treated
Bring the gun directly to the area to be sandblasted and apply it closely
Press the trigger and perform the appropriate manipulations to clean the surface
The length of time the trigger is held in one place depends on the complexity of the area being treated.

Manufacturers are silent about the fact that pistols with recuperation also have their drawbacks. The main disadvantage is that not only sand accumulates in the bag, but also particles of rust, paint, etc. That is why the sand that accumulates in the bag must be sieved regularly to prevent clogging of the nozzle and channels when reusing abrasives. The video below shows the process of how to work with a sandblasting gun with recovery.

How to use a sandblasting gun - basic recommendations

If you understand the principle of sandblasting, then it will not be difficult to master the tactics of sandblasting the surface in order to remove corrosion, paint, varnish and other contaminants. Before starting work, you should prepare the workplace and put on protective clothing. Let’s consider in detail what the process of preparing for sandblasting is:

Selecting a work location. It is best to carry out work indoors, since sand scatters over large areas, which complicates its assembly and is also harmful to the environment, depending on the type of abrasive used. Work can be carried out outdoors if it is necessary to remove rust or paint from a gate or fence, as well as other large surfaces
Lay oilcloth or linoleum on the floor. This is necessary so that after finishing the work it is easy to collect the sand and use it again
Provide good lighting in the room. This is very important, since working in a poorly lit room will result in untreated areas. During work, visibility is reduced due to dust clouds
Remove all unnecessary items that do not need processing. If the flow from the gun gets onto the surface, it will damage it.

It is important to choose the necessary protective equipment when carrying out work:

Special safety glasses. The following requirements apply to glasses: they must fit snugly to the body and be made of glass. Plastic glass will reduce visibility if sand gets on it.
Respirator - and you need to use not a simple mask, but a full-fledged respirator, especially if the work is carried out indoors
Thick clothing and hat

After this, you can begin sandblasting work. There are no difficulties with their implementation, since the essence is to remove the surface coating from the workpiece. Depending on the type of material being processed, you need to adjust the pressure and sand supply, and then begin processing. The gun must be held at an angle of 45 degrees to the surface being treated, since it is at this angle that the effect of particle separation from the surface is maximum.

This is interesting!
The duration of holding the tool in one area depends on the thickness of the layer being removed from the surface, and is established experimentally. After finishing the work, the surface must be degreased, and you can begin painting work.

Choosing sand for a sandblasting gun

An important question when treating surfaces with sandblasting guns is which sand to choose. Many inexperienced craftsmen use ordinary street sand for such purposes, which ultimately leads to rapid failure of the equipment. In addition to the fact that street sand contributes to the disabling of the nozzle, it can also damage the surfaces being treated. When choosing consumables for sandblasting guns, it is important to consider the following factors:

Fraction size - depends on criteria such as nozzle diameter, compressor pressure and the desired result
Material hardness - a 10-point scale is used for evaluation. It is not always necessary to choose sand of high hardness, as it depends on the type of material of the surface being treated
Abrasive ability - this parameter characterizes the time during which the consumable material will cope with the task. The higher the abrasive ability, the greater the amount of work that can be completed in a short period of time.
Recovery ability - this parameter is important to consider when using a special tool with a sand collector

Four types of sand are used for sandblasting:

Quartz - characterized by low cost and availability. The material is characterized by a large amount in its composition, which has a positive effect on the quality of processing. The disadvantage of quartz sand for sandblasting is that it is harmful to health, so work must be carried out strictly using protective equipment, and there should be no people or animals nearby.
Corundum is a material that is excellent for working with high-strength coating materials. Corundum sand is capable of recovery, and it is used in a variety of fields
Garnet is an abrasive material that is environmentally friendly, but it is used on equipment that operates on high-pressure water.
Cooper slag has a high density of abrasive substances, and at the same time it can be used for re-processing. The composition contains quartz particles that are harmful to human health, so it is important to wear protective clothing when working.

When choosing sand, you also need to consider what type of sandblasting equipment is used. These can be closed or open type devices.

This is interesting!
Only dry sand should be used for sandblasting.

Accessories for a homemade sandblasting installation

Before assembling such a device, it is important to prepare all the components. Most of the tools and supplies are usually found in every workshop, but some items will need to be purchased at a hardware store.

The creation of a sandblasting installation should begin by installing a container that will contain an abrasive substance. It is convenient to use a used gas storage cylinder as a reservoir. It is made of durable, high-quality metal designed to withstand heavy loads. The container is sealed, so it is difficult to introduce an abrasive substance into it. To facilitate the process, a small piece of pipe is welded on top. Material is poured into it, and it gets inside through the neck.

Waste gas storage cylinder

It is important to disassemble the container with care, since old gas cylinders most often contain gas residue.

The correct choice of compressor has the greatest impact on the quality of sandblasting. The main problem is the high cost of such an installation. Factory options with sufficient power will be expensive, reducing the savings effect. An alternative option is to make it yourself from inexpensive components.

You can assemble the device at home using compressor heads installed on a ZIL or MAZ pneumatic drive. The power of the installation with the specified components will be sufficient to process any automotive parts. The heads must be equipped with a receiver. To reduce costs, it is made from a liquefied gas storage cylinder. Additionally, you will need an electric motor with a drive and a frame for attaching all elements.

Before you make a sandblasting machine yourself, you should prepare:

ball valves. They are reliable and durable; to be sure of quality, it is recommended to buy products from well-known manufacturers;
rubber hose with reinforced insert from Ø14 mm. It is important to buy a durable option that can withstand increased pressure and abrasive influence;
gas supply hose. Compressed air will flow through it. There are no small grains at the place of its installation, therefore, the diameter is smaller - from 10 mm;
fittings for fixing hoses with other system components. Collet clamps are also useful;
FUM tape - it will be used to create an integral connection of the entire structure of the installation, especially areas operating under pressure.

Read also: How to find out the verification interval of electric meters

Fum tape 0.2mmx19mmx15m Sigma

Do-it-yourself sandblasting like this without a compressor will cost about $35. The savings are significant, allowing you to save most of the cost of a new device. Now you should move on to creating a homemade sandblasting machine.

Which compressor to use for a sandblasting gun

Before using a sandblasting gun, you need to pay attention to the choice of compressor. It should be noted right away that a low-performance compressor is not suitable for sandblasting work. The minimum output pressure must be at least 5 atmospheres. The productivity should be at least 300-400 liters per minute, and ideally 500 liters per minute. When choosing the main device, it is important to consider the following parameters:

Pressure
Compressed air consumption level
Consumption of abrasives
Speed of work
Compressor type

We decide on these parameters, on the basis of which the compressor is selected. Below is a table from which you can roughly calculate the consumption of abrasive substances depending on the diameter of the hose for sand and air, as well as the size of the nozzle and the pressure of the compressor. The values given in the table are approximate and allow you to navigate depending on the volume of planned work.

An important parameter of a compressor for a sandblasting nozzle is pressure. This parameter affects not only the speed of work, but also its quality. If the nozzle diameter of the nozzle is 6.5 mm, then a compressor with a minimum pressure of 4.2 atmospheres is suitable. For nozzles over 8 mm, equipment with pressure ratings of 6.6 atmospheres or more is required.

This is interesting!
It is necessary to take into account the fact that up to 15% -20% of pressure is lost in the connecting air hose.
Another important factor is the type of compressor. They come in piston and screw types. Piston compressors are more popular, but their disadvantage is that the compressed air contains particles of an oil mixture. This causes the sand to become wet, thereby reducing productivity and also reducing service life. To eliminate air humidification, you need to use special dehumidifiers.

If it is necessary to perform a large volume of work while maintaining high quality, then it is recommended to use screw compressors. They are not only reliable, but also efficient. When choosing a sandblasting gun, it is important to consider the suitability of the tool for the type and volume of work planned.