Understanding Air compressor cfm vs psi vs nozzle size

I have a 450P Viair and I'm trying to figure out if I'll be able to use it for sand blasting, and what it's actually capable of.

What I've gotten from Viair's website is the 450P has 100% duty cycle @ 100psi @ 1.6 cfm

But it doesn't tell me the nozzle size they used for this. So I'm trying to figure out what size nozzle these numbers were determined with so I can use the below chart to determine what CFMs I can actually achieve when fitting an HVLP paint sprayer, sand blaster, etc.

http://azglassclasses.com/Reference/CFM-PSI.htm

Anyone know?

 

Yes. The compressor air flow at 100 psi is 1.6 cfm. This means when the compressor is running at 100 psi, it will deliver 1.6 cfm. Whatever is on the end of the hose doesn't matter.

You really need to look at the parameters of your sandblast equipment. The HVLP will likely require less air pressure and flow than the sandblaster. Then you will be able to select a compressor with adequate air delivery based on the greatest requirment. Always size the compressor air delivery above the actual needs. It is not advisable to run the compressor at 100% duty cycle.

The nozzle chart is the performance parameters for specific nozzles at different pressure. Meaning a 1/16" nozzle with 100 psi will consume 6.4 cfm.

So, in this hypothetical situation with the compressor and 1/16" nozzle. The set up will work. But there are downfalls. The nozzle will consume more air than the compressor can deliver. This will place the compressor into a 100% duty cycle. While working, once the tank is depleted, you will need to stop work to allow the compressor to catch up.

Using this compressor, only the 1/64" nozzle is suitable for continuous work at 100 psi. The 1/32" nozzle will have a tendency to run the compressor short on air. Meaning occasional work stoppage.

Select the air compressor based on the equipment on the end of the hose. Back to the example of the 1/16" nozzle at 100 psi needing 6.4 cfm. The compressor to feed this nozzle should be in the 10 cfm or greater range when operating at 100 psi.

So, at what pressure and air delivery does your sandblast equipment need?
Same question for your HVLP equipment?
This information will be in the paperwork for the equipment.

 

These are what I'm looking at getting. I may also need a slightly larger hlvp nozzle for a bed liner project in the future that needs 1.6mm nozzle minimum...if I can make it work anyway. I'm not set on either of these if you have better recommendations. Please send them my way.

I'm thinking I won't be able to sand blast with a portable compressor...the reqs may be too big, or the nozzle too small to blast something large like a front bumper. But might be able to get away with the spray gun.

HLVP spray gun kit

YaeTek HVLP 2-Spray Guns Kit Paint Base Primer, Air Gravity Spray Gun Set 0.8mm & 1.4mm Nozzle with Gauge, Auto Gravity Feed Painting 2-Sprayer Paint Gun

https://www.amazon.com/dp/B0756CZMP9/ref=cm_sw_r_cp_apa_fabt1_orXQFbJ1DDXAM?_encoding=UTF8&psc=1

2 spray guns require 2.1 SCFM and 0.7 SCFM at 40 PSI respectively.


Sand blaster

$55 LE LEMATEC AS118 Sand Blaster Gun Kit for Air Compressor, Paint/Rust Remover for Metal, Wood & Glass Etching, Up to 150 PSI Blasting Media for Aluminum, Sand, Walnut Shells & Soda Blaster Jobs, Blue

https://www.amazon.com/dp/B01M0CRUUM/ref=cm_sw_r_cp_apa_fabt1_ipXQFb5SMTE0M?_encoding=UTF8&psc=1

It recommends an air compressor that can maintain over 90-150 PSI with a minum cfm of 4.0 for optimum results. An air compressor inline air filter is needed and not included. But doesn't say the nozzle size.

The twin ARB has a much higher CFM as I recall. Perhaps I should have gone that route...

 

Great explanation.
Only thing I will add is power requirements.
Rules of thumb...
You can usually get high pressures but low volume.
You can also get low pressure and high volume.

When you want both, you need more power.

 

Good point. I'm trying to stick to an onboard air setup as I'm always moving around and never have a garage for projects/storage. So power limitations would be what the truck can provide. I have a 27f northstar battery.

 

I think you're going to want to use a larger compressor with a storage tank. That portable may be able to do it, but won't last long doing it,,,,, it's a tire filler, not a shop compressor.

 

Gah, I know a shop compressor would be ideal, but between my pressure washer, tool box, and detailing equipment my bed is already practically full...mounting a small tank is probably doable though. I'm trying to stick the compressor in the bedside cubby to keep it out of the way.

 

Yeah I think I have my answer. Even with the ARB I'd be struggling to fill the reqs for a sand blaster, and with the Viair there's just no way. Maybe a very small sq ft paint job, that'd be about all I could manage I think though.

Thanks for the info guys.

 

I'd suggest you will need a 2 cylinder single stage, max pressure 125 psi, unit in the 5-7.5 Hp range driven by a gas engine with a 10-20 gallon air tank. If you need pressure higher than 125 psi, suggest go to a 2 stage unit.

Electric power from you truck is not enough. If you want a unit powered by your truck, look to a unit that would use a belt drive from the engine.

Whatever path you choose.....the Big Box stores likely won't have a compressor that size. You will need to hit the bigger equipment places like Farm Stores or a local air compressor distributor. The compressor distributor will have people on hand that can size the unit for your needs.

One marketing point that sucks many people into the rabbit hole. Higher pressure does not mean more air delivery from the compressor.

 

Another point when selecting a compressor.

Most units will have 2 performance/delivery ratings. 40 psi/X.X scfm and 100 psi/x.x scfm. These will be set based on the maximum compressor power requirements.

 

Gotcha. I think I've heard of someone on here using an air conditioner compressor and adding it to the serpentine belt. I think that was on a 2nd gen. Pretty hefty mod, but very cool. Don't think my skills are up to that yet.