Air Compressor Buyer's Guide: Oil Free or Oil Air Compressor?

January 27, 2012
air compressor
 

An air compressor is a very handy tool, whether you're working on your house or in your garage. It is of great help for a variety of tasks. However, choosing the right kind of air compressor is a tad bit confusing. The most confusion is when you have to decide between an oil free compressor and an oiled one. Here are a few tips to help you make the right choice.

Oiled vs. Oil-less Air Compressors
Air compressors draw air in with a piston. The air is then compressed into a storage tank. For maximum efficiency, the piston chamber needs adequate lubrication, for which oil is used. These are oil air compressors. However, in oil-free compressors, the cylinder is pre-lubricated (mostly with Teflon) for permanent lubrication. The Teflon coating protects the pump. That's the major difference. While oil compressors need regular oiling, the latter doesn't require any lubrication.

Air Compressor Maintenance
Oil compressors require more maintenance than oil-free ones. This is because the oil has to be changed from time to time, depending on the design and the amount it has been used. The user manual specifies how often the oil should be changed. This is not necessary for oil-free air compressors. Moreover, oil-lubricated compressors weigh a lot more than oil-less ones of the same design. This is because they have lesser parts. The air compressor cost for the two are also different. As oil-less air compressor has fewer parts, it costs less. The designs are also simpler.

 

Usage
While oil-free air compressors are cheaper, lighter and require less maintenance, oil air compressors are more durable. As the oil-free compressors are pre-lubricated, there is no constant maintenance and the unit tends to get dry when the Teflon starts wearing out. They don't last as long as oil air compressors. However, the oil-less one might be ideal for home use; if your usage is less. They are very useful for non-commercial purposes. That is the reason why oil compressors are used for industrial purposes and long working hours. Moreover, oil-less compressors tend to turn hotter than oiled ones. This is because there is no oil to cool its components.

Air Compressor Noise
There is a huge difference between the air compression noises of the two compressors. Oil air compressors are much less noisy than oil-free ones. This is an important thing to consider if you are going to be using the compressor in a quiet environment. As they are well-lubricated, they run more quietly. You surely don't want a noisy one at home when your six-month old baby has just fallen asleep.

The bottom line is to weigh the pros and cons, keeping in mind the amount of usage required. After all, this is a one-time investment and it is best to study all available models before settling for the right one.

Buying an Air Compressor
When shopping for a quality air compressor, you will need to decide on what type of unit you will need to purchase. Will you only be using the air compressor occasionally for small jobs? Do you need a larger tank for car painting or restoration? Regardless, of the type of air compressor you wish to purchase, you'll want to choose a machine made by a reputable manufacturer that comes with a good warranty and offers a complete line of accessories and replacement parts.

If you need a good general purpose air compressor, and won't be using it for heavy duty jobs or for many hours every day, one of the best places to purchase a quality air compressor is Sears. Sears offers good quality air compressors made by Craftsman that usually come with warranties between one year and three years. In addition, Sears offers excellent warranty service and support for Craftsman air compressors and makes exchanging them very easy if the need arises. Also, Craftsman air compressors are very competitively priced.

If you need heavy duty air compressors, you should shop for better known brands such as Bosch, Dewalt, Makita or Porter and Cable. You can find retailers in your local area or search the Internet for online dealers that offer these quality air compressors. These types of compressors will be a lot more money than the ones you will find at Harbor Freight or Sears. However, they are made to withstand continued use and offer a good service for many years.

How to Maintain an Air Compressor
With proper care and maintenance, a good air compressor will provide you with years of quality use and service. Proper maintenance will be the difference in a compressor that lasts many years and one that conks out after a few months of use. In order to extend the life of your air compressor, follow these tips to properly maintain it in tip top condition:

  1. Always drain moisture from the tanks - The receiver tank on your air compressor will collect moisture from the air that it is compressing. If you live in a humid climate area, the collection tank will accumulate water quite quickly. You should always make sure that the tank is drained every time you finish using the compressor. Before draining the water, make sure to release the pressure from the air tank.
  2. Clean intake vents - Causing your area compressor to work too hard is the biggest killer of most air compressors. Over time, intake vents will become dirty and cause an air compressor to lose power. So, clean your intake vents frequently to prolong the life of your air compressor.
  3. Change air filters as needed - A dirty air filter on a compressor causes way too much stress on the compressor and almost always shortens its life. So, check the air filter frequently and blow it out. Also, make sure to check and change it at least every six months.
  4. Other types of maintenance- The below is a list of other types of maintenance you should regularly perform on your area compressor to keep it running at its best:
    • Regularly tighten all fasteners
    • Check hoses regularly
    • Test safety shutdown system
    • Clean the fuel tank
    • Occasionally change compressor oil
    • Occasionally change the separator element
    • Clean heat exchangers
 

Related Questions and Answers

What is the Highest Air Compressor Rating?

Different compressors will have different air compressor rating levels. Each compressor will come with its manufacturer's manual where you can find the exact power and usage level of the air compressor. The use of the compressor will determine the power that it generates. For example, if you want to run an impact wrench, then you will need about 5 HP with a 60 gallon tank. For this you will require about 15 amps of power from a 220 volt circuit, but that will still produce about 5 HP of power. For more powerful uses, you will get 110 unit tanks and 220 unit tanks that will do the job for you. Check the requirements of the machine to find out kind of compressor you will require.

What is the Average Cost of an Air Compressor Rental?

There are many sites that will offer you air compressor rentals at different rates. There are so many different types of compressors that getting an average rate is difficult. It's a good idea to check online with comparison websites like Industrial Compressor Services and Sunbelt Rentals that offers many different varieties of compressors at different rates. You might have to give a deposit from a credit card to assure the company that the compressor will be returned. You can also check with quote sites that will compare rates and get you the cheapest rental for your needs.

What is the Most Common Type of Air Compressor Oil?

All oiled compressors will use special air compressor oil types for lubrication and for function. The lubricant that is used in oil based compressors can be of several different types. Three types of synthetic oils are very common and they are air-line lubricants, flurosilicones and phospate-ester based oils. Most air compressor companies will specify the kind of air compressor oil that they require. Check the manufacturers instruction manual to get details. Pre-packaged compressors oils are readily available and you can choose the right product from them. The most reliable company is Castrol, but other manufacturers also have several different varieties that you can choose from. As a rule of thumb, choose any 30 weight Non-Detergent based motor like the 30W/ ISO100 or the 20W/ISO68 oil for your compressor and you should be fine.

What Can I Use for Air Compressor Noise Reduction?

You can carry out air compressor noise reduction with a few simple moves. You can use sound dampers that will block the sound and prevent it from spreading. Apart from a separate room, you can also use expansion chamber mufflers that will block much of the sound from the air compressors. These absorptive mufflers are much like standard auto mufflers and they work well to block low frequency sounds. Another option is to use intake silencer filters that will silence the air intake into the inlet hole. You can buy the silencer and muffler, and get them installed onto your air compressor. The most popular option that is available is the use of soundless compressors that work very quietly. But that will involve buying a new compressor and it can be expensive.

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