What size air compressor has worked for you??

brum1

brum1

Well-known member
Gentlemen,

Looking to move from spray bombs to spray equipment. Have much opportunity to spray components, fenders, etc. What type of air compressor has worked for you?? (HP/cfm at required pressure to spray cars) I am not a professional so painting will be occasional,

You feedback is appreciated,
 
I can tell you that a Craftsman 25 gallon / 5 h.p. compressor is utterly inadequate. You'll be standing around as it puffs away trying to keep up with sandblasting, running most air tools, and presumably paint guns as well. It does a swell job at filling tires, but that's where it ends.
 
I have a 7 hp 2 stage compressor with 80 gallon tank. It will run my blast cabinet or 2 spray guns at once and still unload.
It will also run my 1/2 inch die grinder and unload.
For painting be sure you have a good water/moisture trap.
I used to paint with a 5 hp 2 stage compressor with 60 gallon tank and never ran out of air. I set my tank cutoff at 125 psi.
 
Greg is right. May as well buy a good compressor that will last. That means do not buy a 110 volt compressor, nor a dual voltage compressor. A true 5 H.P. compressor will be 220 volt, and buy a dual stage oil type compressor. Don't buy an oilless compressor.
 
IMHO a serious car hobbyist needs a compressor that will deliver at least 14-15cfm at 90psi, with at least a 60 gallon tank. Such a compressor will require 30 amps at 220 volts, delivered through 10 gauge wire at minimum if close to the breaker panel, preferably 8 gauge.

It will probably be a two-stage unit. One with a 1725 rpm motor is preferable to one with a 3450 rpm motor, as it will be quieter and last longer.

Joe
 
TP Tools carries top of the line Quincy and Champion compressors for restorers:

http://www.tptools.com/dg/91_5-75-HP-Electric-Air-Compressors.html

Media blasting generally takes a large high cfm (10-15 cfm actual delivered air or greater) compressor depending on the nozzle orifice size which controls the cleaning rate per minute and 5 to 7.5 hp models do well for the serious restorer and this will generally cover painting needs also. Downside = $$$$$. Smaller cheaper 3 hp compressors (7-8 cfm actual delivered air) will work but are much slower. Make sure the cfm rating is actual delivered air and not the cylinder displacement volume which some some dealers use in their ratings and duty cycles are important too if you're going to be running it for a long time. Hope this helps a little.
 
It all depends on what you are going to buy and use.


If you plan on doing whole cars with a real HVLP gun you need a decent amount of air. You also need to be able to filter and flow the higher volume of air.
It helps to run through some metal pipe for a distance to help cool. I have two moisture separators. One at the tank and the other after 30' of copper 3/4" pipe. I do not have problems with water.
You will also want to get only 3/8 disconnect couplers. They have twice the area of the 1/4" connectors. The larger flow means the pressure stays constant. With the 1/4" connectors I got a slight drop in pressure once the flow started and the gun behaved different.

The are lots of types of compressors.
The cheap ones have small motors. Ya some say 5 HP, but they are toys. I think the 5 HP special rated motors are off the market today, but if you look at used units keep in mind a real 5 HP 220v motor takes 22 amps.

The cheap units make work fine for you. If you just do a little now and then. The bigger jobs you will have to wait for the compressor to catch up like when using a glass bead booth. At least the cheapo special 5 HP unit I had for a while did that. Plus they sound like they are beating themselves to death.

The 7 HP units are sometimes 5 HP compressors with 7 HP motors. They change the pulley's so the compressor is spinning faster to get the CFM. They self destruct in time if not maintained.

Some of the better 5 HP units will run forever with little or no maintenance.

In my area, I see 5 HP 220V units in the $300 to $500 range all the time on criagslist. I bought my real 5 HP unit for $300. It was built in 1946 with a 60's vintage motor. The tank developed a rust hole and it got relocated on a tank from a 7 HP unit that self destructed from lack of maintenance.
Keep mind that the 1946 pump on my compressor is still being sold new today with slight changes.

When buying an older unit please pressure test the tank first. Look up on the web how to pressure test. You basically fill with water and then add grease until you hit the target pressure. Also look up exploding air tanks to get an idea of the destructive forces in you air tank.
 
i use a 5 hp Quincy V4 very adequate for a small shop i use a blast cab and die grinders da,s you name it no complaints here
 
When you are choosing a breaker and wire think if you would also want a welder,it is easier to run wire 1 time, and the compressor can plug into the welder outlet.
 
Most will recommend a 5hp minimum and if your budget allows they are absolutely correct. However the 5 HP was just out of reach for me so I compromised on a 3HP 60 Gallon 11 CFM Ingersol Rand that runs off 220. The 5HP was about $300 more. It's a great unit and was just enough for the IWATA HVLP gun I chose to shoot with since it only requires 10 CFM. It was the lowest consumption high end gun I could find and worked wonders. The cheaper models seem to use way more air so keep that in mind. Also HP is not always apples to apples. I also have a 3HP Cambell Hausfield POS and it does not pump nearly half the air the rand does.

Moral of the story, 5 hp is the way to go and if you are gonna try anything less make sure you pay attention to your gun selection. If I was gonna paint more cars I would have sprung for the bigger unit but just couldn't do it at the time.

Bob, NJ
 
I run a glass bead cabinate for blasting carbs etc. Gave up on the oiless type and invested in an Ingersall-rand 5 hp 60 gal tank works fine for me, Was $1000 new and delivered to my shop free. There deadicated 220 V.ken ct.
 
I have a 2-stage 220-volt compressor and a proper piping setup, and like everybody else in this thread, I'm glad I got it. Here is one other recommendation: Get one of those spring-loaded reels with 50 feet of hose, and mount it in a convenient location. Then you will never be tripping over tangled piles of hose.

Doug
 
I use a 220 volt, 5 hp, 80 gallon tank. It works great for HVLP paint guns and my barrel blaster. It cost $1000.00 at a local tool store.
 
I see lots of emphasis on horsepower. Manufacturers of budget-priced compressors and other electrical equipment are notorious for making inflated--sometimes wildly inflated--claims about the hp of their motors. Sears and others base their hp ratings on locked-rotor current draw--the current drawn for a very brief time when power is first applied to a motor with the rotor locked in place. They often call it "Rated HP" or "Peak HP." This allows them to claim as much as 7 hp for a motor plugged into a standard 110 volt outlet. The fact is, even a 20 amp 110 volt circuit will not deliver 3 hp worth of watts, and the more common 15 amp circuit will just barely deliver 2 hp.

Manufacturers which are rating their products honestly, and including allowances for losses in wiring and in motor efficiency, will instruct the installer to run a dedicated 30 amp 220 volt circuit for a compressor in the 5-7 hp range. This requires 10 gauge wire for short runs and 8 gauge wire for longer ones.

It's much better to compare cubic feet per minute--usually at 90psi--than horsepower, when evaluating air compressors.

Joe
 
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