Usually, it is more convenient to buy a gas air compressor than to build one. This is because building on requires some level of expertise and precision.
However, you can build one with enough pressure power to run air tools. You will be needing an air tank, a gas engine, unloader valve, mounting plate, throttle control valve, and more.
Let’s begin by exploring the meaning of a gas air compressor and then how to build one.
Table of Contents
What is a gas air compressor?
A gas air compressor, as the name implies, depends on gasoline to run rather than diesel or electricity. Basically, it increases the pressure of a gas by reducing the volume of the gas and this compression of the gas causes its temperature to rise.
Gas air compressors are used in various ways from pressurizing aircraft cabins, moving heat in refrigerators, compressing intake air in a gas turbine, storing purified gases, and supplying air for air brakes. The applications of gas air compressors are numerous.
Gas compressors are portable and powerful enough to run an air tool. However, they are not only suitable for indoor jobs. They can be taken to job sites or workshops when there is no electricity available. This is because compared to an electric-powered compressor, gas air compressors do not need to be connected to any power source.
However, to avoid the risk of health issues, it is advisable to run a gas air compressor in an open-air environment.
Steps to building a gas air compressor
- Purchase an air tank and ensure it comes with a mounting plate. — Take the measurement of the holes for the safety value and air input. This will be useful to you in the later stage of the building of the gas air compressor.
- Fix the compressor on the mounting plate. — To do this, ensure you make use of a bolt size, ½” TPI, and ensure the nuts you use are roughly 1.5 inches.
Buy a horizontal shaft gas engine. Ensure it is not a gear reducer and it should have a rating of at least 5 horsepower.
- Place the gas motor on the mounting plate as well. — Position the drive wheels and obtain the measurement around the region the drive belt is meant to be set.
This measurement will help you purchase the right size of drive belt and install it correctly.
- Ensure you make the position of the motor mounting holes on the mounting plate before removing the gas engine. — Then, make a puncture at the middle of every engine mounting hole position.
You can do this with a center punch. Place a second punch mark at ¾” before, at, near, or towards the initial marks.
Finally, drill the 3 holes at every point using a drill bit of 7⁄16“.
- Join the holes you drilled to create a slot using a rotary tool. — Repeat this at all engine mount bolt positions.
Set the gas engine again on the mounting plate, then loosely install a ⅜” by 16 TPI by 1.5″ bolt at every one of the mounting hole.
Set up the drive belt as well on the pulley of the engine and the pulley of the compressor.
- At this point, ensure the belt is firm enough. — When the tension is right, it will be possible move the midpoint of the belt down at ½”.
Once this is in place, screw in the bolts tightly. Fix the unloader valve into the airline thread about compressor.
- Move on to mount the throttle control valve on the gas engine and connect it to the throttle linkage using a cable. — The method of mounting will differ with the model of the engine.
- With some compression fittings and a ¼” nylon airline tubing, connect the throttle control value to the unloader valve. — Secure the throttle and airline tubing with cable clamps.
Position a brass pipe tee to the check valve.
Ensure the check valve and tee and both either ¼” or ⅜” then set-up the tee on the check valve using an hole to the side.
- On the open side created on the tee, install the air pressure gauge. — Then install the male air hose and tighten it using hose clamps.
- Next, using a piece of 3/8 air hose that is one foot long, connect the tee to the unloader valve. — Also, set up the safety release valve inside the air storage tank.
- Inspect for air leaks and determine the oil levels in the compressor and gas engine. — Proceed to turn on the engine and ensure the throttle is functioning properly.
How do gas air compressors work?
As mentioned earlier, gas air compressors and gasoline-powered air compressors with important elements.
To figure out how a gas air compressor functions, we first have to understand how each of its components and their working systems.
The two most important components are present in every gas air compressor include:
- Air end
- A gas engine
Air end
The air end is the place in the air compressor where the compression actually takes place; that is, the air end is responsible for compressing the air in a gas air compressor. The air end is a screw element in the heart of an air compressor.
The air end draws in air from the atmosphere and forces it into a compact space, when these air molecules are pressured together, the air is compressed. It comprises rotors and it is also the important part of the rotary screw air compressor.
They supply the same amount of air at a given speed but at different pressures. They are important because they supply stable, non-pulsating air flows with fewer vibrations, maintenance, and increased lifespan.
A gas engine
The gas engine works in conjunction with the air end. While the air end compresses by forcing air molecules into a compact space, the gas engine is the power source required to move the air end. The gas engine converts gasoline into motion which will force open the air end and help compress air.
Gas vs electric compressors
First off, both gas air compressors and electric air compressors do an excellent job in an air brake system and there is no significant difference in their performance.
However, they differ in other areas and each have their advantages and disadvantages.
Gas compressors
Now, why would you choose a gas-powered compressor in the first place? The primary reason would be that they do not require an electrical hookup. If working in a place where you need the electric air compressor at a distance far from where you can plug it into a light source, you might need an extension box. This might also not be possible with some electric compressors.
With a gas compressor on the flip side, as long as the tank is filled, you can move around with it from location to location outdoor without bothering about the electric source.
However, although the gas compressor can be used for outdoor projects or jobs, it is not advisable to use them indoors because of the risk of health problems due to the dangerous fumes it releases.
It is highly flammable and this is also a huge risk whether it is being used indoors or outdoors. This means that it also requires regular maintenance.
Another difference is the use of a pilot unloader valve which opens and closes depending on the pressure in the tank. Ideally, this should be done by an automatic machine designed to power up and shut down the gas compressor.
Consequently, the gas compressor runs continuously and is best for projects where constant pressure is needed. They are also quite large and heavy. Therefore, easy mobility is not obtainable here.
Electric compressors
Electric air compressors are generally more convenient than gas compressors and less expensive. They are much more versatile, lighter, less bulky, and come in various styles and sizes. This is why they are more common and mostly used.
As long as you have a power outlet at your worksite, an electric compressor is a more ideal option. In most cases, you will find that an electric compressor has an automated mechanism that starts the motor when the pressure reduces below a particular value and stops the motor when the pressure in the storage tank gets to its upper limits.
The main disadvantage is the fact that it needs a power source for it to run. They also do not do well at heavy-duty jobs, they function better for indoor repairs and jobs.
In general, your choice of air compressor; whether gasoline-powered or electric air compressor, is dependent on the specific application.
