cfm and compressor questions

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teamdooracer
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Re: cfm and compressor questions

Post by teamdooracer » Tue Jun 10, 2014 11:42 am

Are you guys buying direct from Eaton? I will be ordering a compressor shortly and am going to price an Eaton and castair.

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Re: cfm and compressor questions

Post by Detective Coating » Tue Jun 10, 2014 11:45 am

teamdooracer wrote:Are you guys buying direct from Eaton? I will be ordering a compressor shortly and am going to price an Eaton and castair.
My friend that bought one, got it directly through Eaton. I haven't ordered one yet.
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teamdooracer
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Re: cfm and compressor questions

Post by teamdooracer » Tue Jun 10, 2014 1:32 pm

Are you guys going with the industrial or the premium compressors? Curious what the difference is. Specs and price are indentical.

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Re: cfm and compressor questions

Post by bigpimpdx » Tue Jun 10, 2014 11:47 pm

teamdooracer wrote:Are you guys going with the industrial or the premium compressors? Curious what the difference is. Specs and price are indentical.
Mine is coming straight from Eaton, only difference between the industrial and premium units is the color of the tank and in some models, such as the 10hp version, the tank size is only 80 gal whereas the premium is a 120 gal.

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Re: cfm and compressor questions

Post by 9guy9 » Tue Jul 08, 2014 9:02 pm

I may be a little late on this one but anyways. When I was compressor shopping I was looking at these same units. All the $2kish 4cyl compressors use a asian clone of the saylor beal 707 pump. It is actually designed to be used with a 15-20hp motor and spun around 1500rpms to make lots of air. What companies are doing is slowing it down with smaller motors, which is good in every way, except air output. With a 7.5hp motor they spin around 600rpms which keeps them nice and quiet and running cooler. Compare that to units with smaller prizes mps that have to spin much faster to make the same air. For example the 7.5hp IR that lots of guys have spins at 1200rpms.

I ended up buying a used 3phase castair and putting a single phase motor on it. I was planning on a 10hp motor, but was told by several motor sellers and repair shops to stay away from 10hp single phase motors. They all said something allong the lines of they require way too much current to last long. One guy said if I wanted to burn my garage down he would recomend saving the money and just use matches :lol: so I ended up
getting a 7.5hp motor. Im still using the pulley castair had on the 10hp 3 phase and its been fine for over a year. Should be making around 30scfm.
Last edited by 9guy9 on Wed Jul 09, 2014 4:48 pm, edited 1 time in total.
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Re: cfm and compressor questions

Post by hjeades » Wed Jul 09, 2014 3:40 pm

Good info thanks for sharin.
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Re: cfm and compressor questions

Post by Maglin » Mon Sep 01, 2014 10:00 pm

Wow 2x 10HP compressors. I don't know the amps required for a 10HP single phase motor but I know a 7.5 uses 30amps and requires around 35 on start-up. A Mag starter is required on any compressor that is over 5 HP for that vary reason. Just looked and a 10HP motor requires 43 amps of power. That is crazy expensive to run two of them. I would probably put another 220 gallons worth of reserve tanks on it to kept it from cycling often to cut down on power costs and also to use as an expansion chamber/drier.

1/8" nozzle is at the max of your current compressors cfm output. What media are you using that you need to go to 100psi for? I blast with a 50/50 mix of AO and carbide grit. Works well with minimal dust and I usually blast at 30-40 PSI. Only when I'm blasting something that is powder coated do I even go near 60 PSI. I'm using a Sandblast 40lb presser pot on the cabinet. And I'm blasting with a 1/8" nozzle. Well it started life out as a 3/16" nozzle but it's been around for a while.

Also at those pressers you are breaking down your media a lot faster than at a lower pressure. I don't really see that much more speed going with more pressure but I do see a lot more dust and grit breakdown. These is just IMHO. I would get another 5HP compressor unless you really want to spend the coin to get a 500 lb pressure pot. My buddy just recently got rid of his 500 lb Clemco. That thing is massive and a PITA to load unless you put a conveyor feeder on it.

You can always turn a VW engine into a 200 cfm gas compressor. They work great and don't actually cost that much to run if all you want to run is a sandblaster. Just need to get a really good drier. I find building a phase change cooler the best option as you can run it's compressor off the VW engine and have it all contained in a small mobile unit.

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Re: cfm and compressor questions

Post by chromiumsteel » Tue Mar 13, 2018 5:28 pm

This chart will give you a good idea of how much CFM you will need for your particular setup.
https://www.raptorblaster.com/technical ... onsumption

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