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brightspark
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it means it can move 8 .5 cubic feet per minute of free air I believe 
size of pump
size of pumpThanks. How reliable are the ratings? I've heard they're usually optimistic...
This is the one btw:
https://www.wecs-ltd.co.uk/product/sip-tn350-srb-air-compressor-06258/
I'm looking to spray a transit so I'm hoping it will be enough.
This is the one btw:
https://www.wecs-ltd.co.uk/product/sip-tn350-srb-air-compressor-06258/
I'm looking to spray a transit so I'm hoping it will be enough.
rtbcomp
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Trouble is specifying delivery volume/time is meaningless for comparing compressors unless you say at what pressure. 16 cfm at 20 psi is less air mass than 16cfm at 100 psi.
A better measure would be swept volume x rpm x no of cylinders, or free air displacement (FAD) which AFAIK is the delivery from the cylinders to atmosphere.
A better measure would be swept volume x rpm x no of cylinders, or free air displacement (FAD) which AFAIK is the delivery from the cylinders to atmosphere.
There are 2 different measurements that tend to be quoted
Displacement, this is essentially how much (uncompressed) air it sucks in and assuming it’s a piston compressor is basically the cylinder capacity x RPM
Free Air Displacement, this is the output of (compressed) air and is measured at a specific pressure, though a manufacturer may quote 2 different outputs at 2 different pressures.
In the case of your compressor, (according to the link) Displacemt is 13 CFM but FAD IS 8.5CFM @ 145 PSI
Where it gets confusing is that people tend to look at the displacement of a compressor in this case 13.0 CFM, they then buy an air tool that requires a similar output but the air tool requires “compressed” air so the FAD figure is more relevant, assuming it operates at or around that pressure. Even mor confusing is that a spray gun will use 40 PSI, or even less if it’s HVLP or LVLP, so your compressor will deliver something between 13 CFM and 8.5CFM @ 40 PSI
To answer your original question, output is dictated by the capacity of the pump and speed of motor, generally you’re stuck with what you have. If it were possible to use a higher speed motor it would likely overheat the pump, and if you fitted a bigger pump it would likely overload the motor.
The air fitting on the outlet does not dictate the output, but it can reduce flow to bigger air hungry tools, the ones supplied by compressor manufacturers do tend to be restrictive, but even if it’s 6mm diameter outlet it should easy feed a spray gun using a nozzle of 2 mm or less
So to sum up, my best guess is that it should be ok, but it is just a best guess
Hope this helps
Displacement, this is essentially how much (uncompressed) air it sucks in and assuming it’s a piston compressor is basically the cylinder capacity x RPM
Free Air Displacement, this is the output of (compressed) air and is measured at a specific pressure, though a manufacturer may quote 2 different outputs at 2 different pressures.
In the case of your compressor, (according to the link) Displacemt is 13 CFM but FAD IS 8.5CFM @ 145 PSI
Where it gets confusing is that people tend to look at the displacement of a compressor in this case 13.0 CFM, they then buy an air tool that requires a similar output but the air tool requires “compressed” air so the FAD figure is more relevant, assuming it operates at or around that pressure. Even mor confusing is that a spray gun will use 40 PSI, or even less if it’s HVLP or LVLP, so your compressor will deliver something between 13 CFM and 8.5CFM @ 40 PSI
To answer your original question, output is dictated by the capacity of the pump and speed of motor, generally you’re stuck with what you have. If it were possible to use a higher speed motor it would likely overheat the pump, and if you fitted a bigger pump it would likely overload the motor.
The air fitting on the outlet does not dictate the output, but it can reduce flow to bigger air hungry tools, the ones supplied by compressor manufacturers do tend to be restrictive, but even if it’s 6mm diameter outlet it should easy feed a spray gun using a nozzle of 2 mm or less
So to sum up, my best guess is that it should be ok, but it is just a best guess
Hope this helps
Nick67GT
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FAD is directly linked to the inlet conditions.
Therefore, atmospheric pressure (altitude) , temperature and humidity have a cumulative effect on the performance of the machine.
Remember that all of the ratings are in standard conditions. If you're high altitude, high humidity or high temperature, you need to correct for that. What that means is that those factors, especially altitude, can greatly change the delivery of an air compressor. Manufacturers can't list every possible condition on earth in their literature, so they came up with what's called standard conditions. Standard conditions are: 68F ambient temperature, sea level, and 0% humidity.
When you see a chart or rating with free air delivery (FAD) it should be associated with a pressure. That is the amount of flow (CFM, l/s, m3/hr, m3/min or whatever unit of measure they might use) that you get from that compressor at that pressure in standard conditions.
Therefore, atmospheric pressure (altitude) , temperature and humidity have a cumulative effect on the performance of the machine.
Remember that all of the ratings are in standard conditions. If you're high altitude, high humidity or high temperature, you need to correct for that. What that means is that those factors, especially altitude, can greatly change the delivery of an air compressor. Manufacturers can't list every possible condition on earth in their literature, so they came up with what's called standard conditions. Standard conditions are: 68F ambient temperature, sea level, and 0% humidity.
When you see a chart or rating with free air delivery (FAD) it should be associated with a pressure. That is the amount of flow (CFM, l/s, m3/hr, m3/min or whatever unit of measure they might use) that you get from that compressor at that pressure in standard conditions.
daedalusminos
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I'd say that compressor is more than capable, but what gun and nozzle are you intending to use? Lesser compressors will put paint on the panel but maybe not with the finish you require.
Thanks.
So from this, we can assume that FAD is 8.5CFM @ 145 PSI. The compressor kicks off at 110psi or thereabouts, what would the FAD be then?
I use PCL fittings, and a 10mm PCL air line. I've also put a fitting into the tank inspection port so I can have an unregulated supply.
Haven't decided on a gun and nozzle yet. I'm only doing a quick blowover so finish isn't the most important factor. I'll probably buy a decent gun in the future, but for now I have a gravity fed gun that I picked up from lidl a few years ago.
So from this, we can assume that FAD is 8.5CFM @ 145 PSI. The compressor kicks off at 110psi or thereabouts, what would the FAD be then?
I use PCL fittings, and a 10mm PCL air line. I've also put a fitting into the tank inspection port so I can have an unregulated supply.
Haven't decided on a gun and nozzle yet. I'm only doing a quick blowover so finish isn't the most important factor. I'll probably buy a decent gun in the future, but for now I have a gravity fed gun that I picked up from lidl a few years ago.
FAD @ 110PSI will be greater than 8.5 CFM but less than 13 CFM, I personally couldn’t say what it might be I would merely be guessing, someone more knowledgable may know better.
Your spray gun will only require 40 or so PSI and FAD for this, pressure will be even more, gravity fed guns require less air than suction fed, and also bear in mind that you are not constantly using the gun as you’re pausing whilst moving from panel to panel, refilling, flashing off etc.
Bear in mind Lidl usually sell that spray gun to be compatible with their 2.5 HP compressor soit should be ok.
Edit to add.
I’ve just re-read the link you posted to your compressor specs, and it doesn’t actually say that FAD is 8.5 CFM @ 145PSI, there is no @ in their description, so the FAD figure is pretty meaningless
Even so I think it will be sufficient for your spray gun
Sorry for any confusion
Your spray gun will only require 40 or so PSI and FAD for this, pressure will be even more, gravity fed guns require less air than suction fed, and also bear in mind that you are not constantly using the gun as you’re pausing whilst moving from panel to panel, refilling, flashing off etc.
Bear in mind Lidl usually sell that spray gun to be compatible with their 2.5 HP compressor soit should be ok.
Edit to add.
I’ve just re-read the link you posted to your compressor specs, and it doesn’t actually say that FAD is 8.5 CFM @ 145PSI, there is no @ in their description, so the FAD figure is pretty meaningless
Even so I think it will be sufficient for your spray gun
Sorry for any confusion
