One of the questions that repeatedly comes up in sandcarving is, “How much compressed air do I need to run a sandcarver?” The following information from Robert Robinson at MediaBlast & Abrasive, Inc. addresses this common question.
This information is based on operating a 3/32″ nozzle machine at normal pressures for sandcarving. Operation using a 120 volt single phase air compressor is not realistic, because holding the 90 to 100 psi pressure for machine controls is not possible.
Choosing An Air Compressor
These two photos show important pieces of the puzzle so you can answer the question of how much compressed air is needed with accurate, easy-to-understand specifications, as well as a cost for the compressor. Below are some features to look for in an air compressor:
- Vertical Tank: Takes up less space
- Tank Capacity: 60-gallon capacity
- ASME Coded Tank: This means you can now have employees working in the area; non-ASME Coded Tanks are fine for your garage but are not allowed for shops that have paid employees and Workman’s Comp. Insurance
- Pressure: This tank has a maximum pressure of 135 psi; you want your Sandcarving machine controls always operating with a minimum of 90 psi, so 135 psi allows you a 45 psi cushion; some models go to 150 psi, but they normally have a duty cycle less than 100%
- Cast Iron Pump: Durable; industrial grade quality
- 100% Duty Cycle: Continuous duty rating; extended operating cycles
- 14 CFM @ 90 PSI: Never be confused by simple displacement with 0-pressure in the tank (hard to pump up a tire with no pressure inside the tank); uses less than six CFM during sandcarving with 6 CFM leaving the tank and the ability to place 14 CFM back inside the tank; this means the air compressor gets to cycle on and off allowing it to cool, which always makes them last longer
- Double the CFM: Over double the CFM required to operate a 3/32″ standard nozzle size; allows you to wear the nozzle and continue to operate; the larger the nozzle the more volume it requires to maintain sandcarving pressure; because 1/8″ nozzle uses 10 cfm at sandcarving pressure you can also occasionally use the larger size (NOTE: if you are always going to use the 1/8″ nozzle then we advise a larger capacity air compressor and possibly more dust collector or semi-automatic cleaning cycle)
- Oil Gauge: Oil gauge with visible sight glass
- Switch: Electrical switch supplied
Robert Robinson draws from four decades of experience in the sandblast machinery manufacturing industry. In 1977, Robinson founded Media Blast & Abrasive, Inc., manufacturer of the CrystalBlast line of sandcarving and etching machinery. Media Blast & Abrasive partners with IKONICS Imaging to offer the sandcarving industry a complete line of machinery, photoresist, and expertise. For more tips on buying the right air compressor for sandcarving, check out this article that Robinson wrote.