Sandblasting is a universal device that is used in industrial and domestic conditions. With it, you can clean the surface of the layer of the old coating, pollution, traces of corrosion.
There are several ways to become the owner of a device so useful in the household. The first is to buy a ready-made version in the store. This is the easiest way. Its only negative is the high cost. The second way - to collect sandblasting with your own hands. This will require some effort, but in terms of material costs, this method is much more economical.
The principle of operation of the device
To understand how to make a sandblasting machine with your own hands, you need to know the principle of its operation. It is similar to the operation of a spray gun used for spraying paint (and other coatings).
The main element of the installation is the compressor. It pumps air, creating the right pressure in all highways. Passing through the installation, air creates a vacuum. Due to this, the abrasive material (sand) is mixed with air and enters the main highway. From there, the flow passes to the nozzle, through which it exits. At the exit, a stream of air is created with sand, which moves under high pressure. It is he who is sent to the treated surface.
The scheme of the sandblasting apparatus is shown in the figure.
Key Installation Features
A home-made sandblast consists of the following parts:
- electric cable for connecting to an electric network;
- hoses of a certain diameter;
- connection for connecting elements;
Nozzle
Another important element is the nozzle, without which the device will not be able to perform its functions. The nozzle for a sandblasting apparatus at the enterprise is made of steel and coated with boron or tungsten compounds. This gives the parts wear resistance. Less commonly used are ordinary steel, ceramics, or cast iron. But such elements quickly collapse under the influence of a stream with abrasive material.
At home, the nozzle for a sandblasting machine can be turned on a steel lathe using old spark plugs as a material. To do this, take out the metal electrode, which is located inside the candle. True, such a mechanism is characterized by a short service life, because it wears out quickly. But its cost is very low.
Types of devices
The device described above is typical for suction sandblasting equipment. But this is not the only device option. There are only 3 types of sandblasting:
- Suction. This option is easiest to make at home. It is suitable for mild surfaces. This option is different in that the air takes sand from the container and delivers it in the form of a stream.
- Vacuum. This type of equipment operates in a cyclic mode. This means that the abrasive material is ejected to the surface through the nozzle, after which it is sucked back into the chamber for reuse.
- Pneumatic. Apply this type of equipment to work on large areas or in difficult to clean places. Home-made sandblasting of this type is a dangerous device in terms of safety. Therefore, it is not recommended to collect it. This is due to the high pressure in the system and high power.
Air or water may enter the abrasive feed device. The first option is more common, as its design is simpler.
Abrasive feed
Abrasive can be supplied in two different ways, depending on what sandblasting machines are divided into injection and pressure.
Pressure apparatuses are characterized by high productivity and intensity of work. In them, air enters simultaneously into the apparatus itself and into a container with sand.
The injection method of sand supply is notable for low pressure, so it is used when sandblasting is done with your own hands. In this case, air and abrasive material move along different highways.
What you can assemble yourself
Making devices at home involves the use of materials that can easily be found in your garage. In addition, simple designs that work efficiently are used. Given this, you can be guided by a simple scheme, without any drawings.
As a container for abrasive material (receiver), where you should fill the sand, you can use a gas cylinder. The cylinder filling hole is located on top. Air under pressure will enter the receiver through a nozzle mounted in the upper part of the container and exit with the sand through the outlet hose located below.
Materials for the manufacture of the apparatus
Drawings of the sandblasting apparatus make it clear which details are necessary for its manufacture and in what sequence they need to be connected. One of these drawings is shown in the figure below.
The need to purchase a compressor, which is the main element of the device, was discussed above. Its performance should be at least 800 liters. An oil separator will be required to prevent the sand from getting wet.
In addition to the compressor, you will need a container to accommodate the abrasive material. Very often, a gas cylinder is used for this, the capacity of which is 50 liters. Its design allows it to withstand high pressure inside and mechanical damage outside.
A filter for running water is suitable, in which it is possible to replace the filler. Instead of a filter element, silica gel in balls will be poured into the flask (you can buy it at a pet store). The filter is necessary to dry the air before it is fed into the receiver.
The duration of continuous operation largely depends on the selected nozzle. Inexpensive options (cast iron or ceramic) are designed for several hours of operation. In some cases, they withstand only a few tens of minutes. Therefore, it is better to give preference to parts made of boron carbide or tungsten carbide and capable of withstanding hundreds of hours of intensive work.
In addition, the following parts will be needed to assemble the device:
- oxygen hose for air supply (5 m long and 10 mm inner diameter);
- reinforced hose (2 m long and 2 m inner diameter);
- fittings for hoses for connecting individual parts of the device with a rubber hose into a single system;
- ball valve made of brass (2 pcs.).
- pipe with thread and plug (neck will be made of it);
- a piece of pipe with the same diameter and three barrels;
- sealant for compounds (fumlent).
When all the parts are assembled, you can begin to assemble the sandblasting machine.
Assembly steps
Homemade sandblast is assembled in the following sequence:
- Balloon preparation. If a used cylinder was purchased, it must be freed from gas. To do this, the valve is completely twisted. The entire tank is filled with water, which will displace the remaining gas. After that, working with the cylinder will be safe. Instead of a neck we fasten a branch pipe with the spherical crane. A tee is screwed into it from above, into which two fittings are inserted.
- Supports are welded from 3-4 pieces of reinforcement from the upper side of the cylinder. Their length should be sufficient so that the crane does not touch the ground.
- A hole is made in the middle of the bottom of the container where the tee is welded. One tap is required for cork. The second is for the air supply hose (a tubular extension is welded). All connections are recommended to be welded to ensure tightness. It is possible to connect with a thread, but then a sealant is required.
- An in-line filter is attached to the tubular extension using a tee. To the tee - a hose, which with the second end will be connected to the fitting at the bottom of the cylinder (near the supports). Connections are fixed with clamps. A ball valve is placed at the inlet of the filter. A fitting is fixed to it, through which a hose going from the compressor will be connected.
- The gun is assembled from the nozzle, which is connected through a piece of hose to a ball valve. The second end of the tap is connected to a metal tube (approximately 30 cm).
At this stage, the home-made sandblast is ready. You can weld handles on the sides of the receiver. Thanks to this, it will be easier to carry.