It occurred to me that not a lot of folks have an air compressor and since I can't live without mine now, I put together this little guide for picking out one.
The first rule of thumb is it's all about the CFM. Ignore the horsepower listed on the motor. Many of the vendors that sell to a big box store use a peak HP number to print on the side of the tank because it's a bigger number. Either go by the continous HP or go by the CFM. But when comparing make sure that they are showing you the CFM at the same pressure. 120 CFM at 100 PSI is actually more capacity that 120 CFM at 90 PSI. Bottom line is look at the tools you have or want to buy and size the equipment appropriatly.
Ignore the size of the tank. A bigger tank won't give you more CFM, only the pump can do that. In fact on very small pumps a large tank will actually force the pump to run harder to recharge the big tank. As the pump is running it's heating the air and suspending moisture in it.
Here is a list of me of the typically tools and their requirements
I used Ingersol Rand for a baseline. Some cheaper tools do not have efficient air motors and will use more
All of these are rated at 90 PSI
3/8" Air Ratchet 5 CFM
1/4" Air Ratchet 3.5 CFM
1/4" Die Grinder 3 CFM
1/2" Impact Gun 4.4 CFM
HVLP Spray Gun 9-15 CFM @ 30 PSI.
Sand Blast Cabinet, Medium Nozzle 10CFM@ 90 PSI
Pressure blaster (depends on nozzle size) 25 CFM @ 60 PSI with 5mm nozzle
Keep in Mind the duty cycle of the tool. While a 3/8" air ratchet uses 5 CFM it doesn't run continously and could probably be supplied from a 3-4 CFM compressor. Air Grinders, sandblasters are the worst they run almost continously and don't give the compressor a break. An HVLP spray gun needs a lot of CFM but notice that it's typically at a lower PSI that what the compressors are rated at. A 7-10CFM compressor could supply a 15 CFM Air gun.
Types of compressors:
If you can afford an oiled piston compressor by all means get one. Your ears and neighbors will thank you. I went from a 2.5 HP Craftsman oilless to a 7.5HP Puma Oiled and my shop got much quieter. The oilless compressors just won't last as long if you work them hard. If you overrun them with something like a sandblaster you'll go through rings and headgaskets faster than an newby with his first TR. (Ask me how I know this).
The first rule of thumb is it's all about the CFM. Ignore the horsepower listed on the motor. Many of the vendors that sell to a big box store use a peak HP number to print on the side of the tank because it's a bigger number. Either go by the continous HP or go by the CFM. But when comparing make sure that they are showing you the CFM at the same pressure. 120 CFM at 100 PSI is actually more capacity that 120 CFM at 90 PSI. Bottom line is look at the tools you have or want to buy and size the equipment appropriatly.
Ignore the size of the tank. A bigger tank won't give you more CFM, only the pump can do that. In fact on very small pumps a large tank will actually force the pump to run harder to recharge the big tank. As the pump is running it's heating the air and suspending moisture in it.
Here is a list of me of the typically tools and their requirements
I used Ingersol Rand for a baseline. Some cheaper tools do not have efficient air motors and will use more
All of these are rated at 90 PSI
3/8" Air Ratchet 5 CFM
1/4" Air Ratchet 3.5 CFM
1/4" Die Grinder 3 CFM
1/2" Impact Gun 4.4 CFM
HVLP Spray Gun 9-15 CFM @ 30 PSI.
Sand Blast Cabinet, Medium Nozzle 10CFM@ 90 PSI
Pressure blaster (depends on nozzle size) 25 CFM @ 60 PSI with 5mm nozzle
Keep in Mind the duty cycle of the tool. While a 3/8" air ratchet uses 5 CFM it doesn't run continously and could probably be supplied from a 3-4 CFM compressor. Air Grinders, sandblasters are the worst they run almost continously and don't give the compressor a break. An HVLP spray gun needs a lot of CFM but notice that it's typically at a lower PSI that what the compressors are rated at. A 7-10CFM compressor could supply a 15 CFM Air gun.
Types of compressors:
If you can afford an oiled piston compressor by all means get one. Your ears and neighbors will thank you. I went from a 2.5 HP Craftsman oilless to a 7.5HP Puma Oiled and my shop got much quieter. The oilless compressors just won't last as long if you work them hard. If you overrun them with something like a sandblaster you'll go through rings and headgaskets faster than an newby with his first TR. (Ask me how I know this).
