piston air compressors

Six Tips for Buying Piston Air Compressors

Piston air compressors are often used with abrasive blast cabinets because they are efficient and cost effective. Available for purchase at many “Big Box” stores, there are a few tips and tricks that you should know before purchasing any piston air compressor.

6 Facts About Piston Air Compressors

  1. Vertical air compressors must pass a safety vibration test so the tanks are normally larger for stability and the pumps smaller for safety. Horizontal air compressors normally pump the highest volume of compressed air but vertical tanks fit nicer is smaller shops.
  2. Two types of piston air compressors are common, single stage and two-stage. Two-stage compressors can store more air volume inside the tank than a single-stage compressor using the same tank size. Comparing 170-psi tank pressure vs. 125-psi tank pressure, you will get to use more air from the tank with the higher psi before the compressor turns on.
  3. Two-stage normally cost more than single-stage; you need to let your budget decide which compressor style you purchase.
  4. Cast iron pumps are normally longer lasting than aluminum pumps with cast iron piston sleeves because often cast iron will have a higher duty cycle and slower pump rpm.
  5. Air compressors are measured in duty cycle, the on time vs. the off time for cooling down. Duty cycle is measured in 10 minute time periods. 50% duty cycle means 5 minutes on and 5 minutes to cool. 100% duty cycle is best, because it can operate continuously without damage. Because manufactures often over rpm their pumps to show better and higher cfm volume numbers, anything less than 100% duty cycle must allow the pump cool to avoid damage. So if you plan on blasting for hours at a time with just enough compressed air to operate the gun size, buy only 100% duty cycle air compressor.
  6. Do your research and buy the most compressed air you can afford for the electrical power supply you have available. You can buy a cast iron single or two-stage vertical air compressor that supplies 16 cfm at 100 psi for around $600.00, or a smaller, single-stage aluminum air compressors that only supply 13 cfm at 90 psi for more than $600.00.

Pro Tip: Buying a smaller abrasive blasting cabinet for any home garage normally means you have a smaller dust collector or smaller dust collector design on the machine. Buying a gun size smaller than you can operate with the air compressor you have available can mean taking 3 times longer to abrasive blast the parts clean. Combining these two things can result in running a smaller less expensive abrasive blasting cabinet 3 times longer and exceeding the limits of the dust collector supplied with the blasting cabinet.  With 220-volt single-phase power you can buy a piston compressor that pumps 27 cfm @ 175 psi but it does cost more!

To Sum it Up

Compressed air can be confusing so this is what we suggest:

  1. Look for a vertical compressor but look for one that turns off at 150 and back on at 130 or close to those numbers. (Either single-stage or dual-stage pump.)
  2. Look at the cfm delivered at 90 to 100 psi never the displacement at zero psi – ideally you want to blast at 90 to 100 psi- next consider the cost of the unit. An expensive air compressor that doesn’t deliver enough compressed air is worth far less than an oversized compressor running on less than 100% duty cycle.
  3. Beware: tank size does not make up for volume required. Some people only want to operate an air impact tool for seconds and some people want to paint an entire car and some want to abrasive blast parts all day and some only a few minutes. All types of compressors have their place but undersize a sandblasting cabinet compressor and the compressor will wear out quickly if not within the month.

Pro Tip: One air compressor is not right for everyone but you can buy a good 16 cfm air compressor for $600 with a cast iron pump or one that is less desirable for $1000 depending on how much homework you do ahead of time.

Media Blast manufactures 170 different blasting cabinets models, Wet, Dry, Siphon, Gravity Feed and Direct Pressure, Light Duty, R&D and Production with special blasting cabinets for Steel Shot, Plastic and Soda. We have a complete line of smaller micro units for special low frictional heat. We want to help you buy the right machine the first time!