An article on how to choose the right compressor for painting a car, what to be guided by when choosing a device. At the end of the article - a video on how to choose a compressor for a garage.
The content of the article:
A properly selected compressor will become an indispensable assistant for its owner. In addition to painting a car, the unit performs many other equally useful functions. It will help inflate tires, blow out hard-to-reach parts of mechanisms, clean the surface with a sandblaster, etc. The possibilities are limited only by the technical characteristics of a particular model.
Step 1. Determine the purpose
If you decide to purchase a compressor for painting a car, then first of all you must answer the question: “Why exactly am I buying a device?”. There will be three answers:
For occasional non-intensive use
Spot-renew a leaky paint layer on a car, touch up peeling sections of garage doors, pump up tires, etc.
For this, a single-cylinder piston compressor with a small receiver volume (up to 50 liters), a capacity of around 150 l / m and a mains-operated one is suitable. The cost of such equipment ranges from about $100 to $200.
For intensive painting work
If you plan to paint surfaces of a large area (the whole car), then you should pay attention to medium-power models: piston, oil, two-cylinder, with a receiver volume of 50 liters or more and a capacity of 300 l/m.
It should be borne in mind that the lower all these indicators, the lower the quality of work.
For example, using a piston two-cylinder oil compressor with a 50-liter receiver, a capacity of 350 l / m and a pressure of 8 atm, it is difficult to completely paint a car, as the equipment will overheat and turn off. But its power is enough to paint the hood or one side of the car.
Prices for medium power compressors - from $ 200 and above.
For professional activities
If you plan to make the compressor work for you, providing services (officially or not at all) for painting cars, then you will have to spend money on equipment of the appropriate quality. In this case, the rule “the more expensive the better” is more relevant than ever, since it is best to get a screw compressor or a professional piston compressor.
However, the cost of the unit quickly pays off, and there are several reasons for this:
- expensive and powerful equipment is able to work without interruption for a long time;
- high cost means not only good performance, but also corresponding quality, hence durability and savings on maintenance;
- the quality of painting will not cause complaints, and a satisfied client is the best advertisement and an influx of new customers.
In addition to the destination, at the initial stage, you should determine the amount that you are willing to spend. This will allow you to immediately reject options that are not suitable for the price in the future.
Step 2. We study the varieties and specifications
Once you have decided on your goals, you can move on to studying the options offered by the market. Compressors are classified according to several criteria.
By design features There are two main types of air compressors:
Piston
They are considered the "father" of all varieties and are the most popular, although they are inferior to screw ones in many qualities.
The principle of operation is based on the reciprocating operation of the piston inside the cylinder, which drives the motor, resulting in the supply of air mass under pressure.
Features of piston compressors:
- ease of operation;
- low cost in comparison with screw models;
- the ability to easily replace many parts in case of failure;
- simple design;
- long service life;
- performance is lower than some other devices;
- resistant to changes in ambient temperatures;
- require regular replacement of certain parts, such as oil seals, piston rings, etc.
Oil-free is characterized by low performance and endurance. But also low cost. These devices are not popular for painting purposes, but if you only need to tint small areas on the car body and other surfaces from time to time, or pump up tires, then this option is fine. In addition, the air mass supplied by such a device does not contain oil impurities, which improves the quality of the paintwork.
Oily is characterized by the presence of oil in the crater of the piston drive. This type of compressor is suitable for household and professional car painting, depending on the features of a particular model.
Piston type compressors can be either direct or belt driven:
Direct drive
The transmission of torque to the crankshaft of the air box is transmitted directly.
This principle of operation has several disadvantages:
- work at high speeds provokes overheating of the equipment;
- the piston compartment is poorly lubricated (that is, oil starvation is possible), which leads to premature wear of parts;
- noisier than belt driven devices;
- in winter, direct-drive compressors do not start well.
Belt driven compressors
Torque is transmitted via a belt. Models of this type are free from the disadvantages of direct-drive products, since the number of revolutions during operation is much lower.
Belt-driven devices are more expensive, but they are suitable for both domestic needs and professional activities.
Screw air compressors
The principle of operation is based on the rotation of two parallel rotors. The leading rotor has a convex thread (slave - concave) and is connected to the motor, with the help of which they are brought into working condition. In the process of their movement, the air mass is first injected into the tank, and then supplied under pressure.
Features of screw models:
- high price;
- uniform supply of air mass due to the absence of unstable mechanical forces;
- durability and reliability;
- the ability to work without overheating for a long period (there is no friction effect, since there is a gap between the screws);
- energy saving up to 30%;
- high performance;
- low noise level;
- high quality painting.
Drive type compressors are of two types:
Stationary (or electric)
It is powered by 220 or 380 V. They are distinguished by silent operation and can be used indoors.
Autonomous (petrol or diesel)
The main quality of such a compressor is mobility. However, for painting a car, this hardly matters; in this case, paint and varnish work is carried out in places where it is possible to connect to the network.
Plus, ICE-driven compressors require good ventilation when working indoors (do not forget about combustion products) and are very noisy.
Step 3. Study the performance characteristics and compare them with your requirements
Before making a purchase, you should carefully study the model passport. What to pay attention to first of all?
Design features
Piston or screw, direct or belt drive, with one or more cylinders, etc. The compressor can have from 1 to 3 cylinders. But it is worth paying attention not only to their number, but also to the size. The larger the volume of the working chamber, the more powerful and productive the unit.
Power supply
If the compressor is mains powered, do you need 220 or 380 V?
Receiver volume
A receiver is a reservoir for the accumulation of compressed air. The larger its volume, the better the quality of painting and the more stable the operation of the unit. For minor repairs, you can limit yourself to 30-50 liters, but for more serious painting work, the volume of the receiver should be at least 200 liters. For professional activities, it is worth looking at more capacious models, from 300 to 600 liters.
Pressure
Denoted by bars or atmospheres. Medium power compressors have a pressure of 2.0 to 5.0 bar, professional screw units - up to 10 atm. When buying, it is worth considering that 1.0 bar of pressure increases electricity consumption by about 8%.
Performance
It refers to the amount of compressed air supplied and is expressed in liters per minute (l/m). Here it is important to compare the performance of the compressor and the requirements of the spray gun. For example, if the spray gun is designed to supply 400 liters of air per minute, and the compressor produces less, then the painting process will be intermittent. Which will lead not only to a loss of time, but also to reduce the quality of staining.
Step 4. We take into account additional nuances when buying
In addition to the main performance characteristics of the model, it is worth paying attention to some features:
- Is the selected equipment equipped with a dehumidifier that prevents moisture from entering the paintwork material, thereby improving the quality of painting work.
- Is there an oil filter and how reliable is it. Poor filtering can cause significant damage to the paint layer.
- The higher the performance of the model, the more additional equipment can be connected to it.
- It is important to remember that the indicators of air mass intake for injection into the tank and the volume of air supplied under pressure are different values and can differ significantly. When choosing, you need to pay attention to the amount of air (l / m) at the outlet.
Video on how to choose a compressor for a garage:
