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Increasing CFM in air compressor

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Forum topic by shelly_b posted 550 days ago 9383 views 0 times favorited 28 replies Add to Favorites Watch
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shelly_b

841 posts in 742 days


550 days ago

I have a 6 gal PC air compressor. I would like to be able to use it with a spray gun for finishing, but I’m pretty sure the CFM is to low (2.6 @90PSI). I really don’t want to have to wait on it to fill back up, or listen to it run all the time. I saw in a magazine where someone made a really neat air tool station that included a portable air tank(not compressor) that was used as a resevior. Has anyone done this? If so, would a 10gal reserve tank be sufficient enough to run a spray gun that requires around 4.5CFM at 40PSI? Or do I just need to get a bigger compressor, or spray station?


28 replies so far

View Stephenw's profile

Stephenw

273 posts in 1009 days


#1 posted 550 days ago

The output of the compressor must exceed the demand of the air tool.

You can get bye with a smaller compressor with tools that are used in short cycles such as impact guns, nail guns, and air ratchets. Continuous demand air tools such as air sanders and paint guns require a compressor that is sized for the tool.

You need a larger compressor.

You could also buy an airless spray gun or a spray gun system that includes it’s own air source.

-- http://www.garagebulletin.com/

View DIYaholic's profile

DIYaholic

13243 posts in 1299 days


#2 posted 550 days ago

I have a 30 gallon oilless compressor, however I have not used it for spraying, so take this with a grain of sand. The manual (& chart on compressor) states that intermittent spray gun use is possible. So, I would say a ten gallon reserve would not be sufficient.
I’m sure others with actual experience will chime in shortly.

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

View Jerry's profile

Jerry

2179 posts in 2171 days


#3 posted 550 days ago

I don’t think the extra tank will be the best answer. The pump on your compressor is not adequate. For 200.00 or a little more an adequate compressor is available.

-- Jerry Nettrour, San Antonio, www.topqualitycabinets.net

View JesseTutt's profile

JesseTutt

802 posts in 734 days


#4 posted 550 days ago

I saw that article; I think it was in Shop Notes. Yes I have a 5 gallon tank that started its life as a portable tank for inflating tires. I converted it so I can connect it as a reserve (additional) tank for the air compressor or I can take it with me to inflate tires or drive a few nails.

Using it as an additional tank reduces how often the air compressor runs. But, it runs longer when it does run. This might give you another minute or two of spraying at full pressure. I agree with StepheW that the best answer is to buy a “spray gun system that includes it’s own air source.” This is what I did with the Earlex 5000 HVLP system and it has never disappointed me.

-- Jesse, Saint Louis, Missouri

View waho6o9's profile

waho6o9

4821 posts in 1201 days


#5 posted 550 days ago

http://lumberjocks.com/reviews/3259

Here’s a review on the Earlex Spray Station 5500

HTH

View Moron's profile

Moron

4666 posts in 2517 days


#6 posted 550 days ago

I’ve seen done, what you ask, many times. You just use your little pancake compressor to fill a larger tank (the bigger the better) and away you go……….works like a charm

-- "Good artists borrow, great artists steal”…..Picasso

View johnstoneb's profile

johnstoneb

642 posts in 797 days


#7 posted 550 days ago

You need a larger compressor. A larger or more tanks will make it longer before the compressor turns on, but it will not increase the capacity of the compressor to produce air under pressure.

-- Bruce, Boise, ID

View David's profile

David

196 posts in 1287 days


#8 posted 550 days ago

10 gallons is about 1.3 cubic feet, so it would only give you a few seconds of extra use on the spray gun before needing to refill. That said, if your compressor puts out 2.6cfm @ 90 psi 4.5cfm at 40psi might be possible. I would check the specs on the compressor output at lower pressures before buying anything else.

I’ve used a 60 year old 1cfm @ 90psi compressor for spraying before, and the spray gun worked fine. My spray gun may not require as much air as yours though.

-- Perilous to all of us are the devices of an art deeper than we ourselves possess. --Gandalf the Grey http://davidwahl.org/category/woodworking/

View shelly_b's profile

shelly_b

841 posts in 742 days


#9 posted 550 days ago

Thanks guys. I haven’t bought a gun yet, but found one on amazon for under $20 with great reviews. If it doesn’t work, it’s only 20 bucks…

View Stephenw's profile

Stephenw

273 posts in 1009 days


#10 posted 550 days ago


David said “That said, if your compressor puts out 2.6cfm @ 90 psi 4.5cfm at 40psi might be possible. I would check the specs on the compressor output at lower pressures before buying anything else.”

I think her compressor puts out 3.5 cfm at 40 psi. It is my experience that the cfm numbers on compressor spec sheets are a little higher than what the compressors can actually produce. The air tools also seem to use more air than the spec sheets claim.

-- http://www.garagebulletin.com/

View CharlieM1958's profile

CharlieM1958

15683 posts in 2842 days


#11 posted 550 days ago

I have to agree with those who are saying the extra tank is not going to help much.

The key is what you plan on spraying. For small projects like a box, or an end table, or a single cabinet, your compressor will work just fine. But if you plan on spraying an entire set of kitchen cabinets at one time, you need a bigger compressor or a self-contained HVLP unit.

-- Charlie M. "Woodworking - patience = firewood"

View Shawn Masterson's profile

Shawn Masterson

1253 posts in 572 days


#12 posted 550 days ago

what you are referring to is called a “PIG” these are use in industrial settings. it is a 30 gallon tank with a supply line in and feeds out the sides. usually red in color and looks like a momma pig with babies on the side. they are set up when the compressor is to far away.
I have a 30 gallon set up in the front of my shop to run my heavy demand tools, grinders and 3/4” impact, but it is fed by a 60 gal two stage compressor with a 3/4”line. In your situation a 30 would work for spraying but only in short burst. also it would take forever to fill up, and this will severely shorten the life of your compressor because they are designed to cycle, limiting the heat build up on the head. an oil type my last longer, but still wear faster.
your best bet is to go bigger. something like this would serve you just fine
http://www.ruralking.com/industrial-air-60-gallon-oil-lube-stationary-air-compressor-135-psi-c3706056.html

also the HF spray guns work great and can usually be had for $9.99 on sale good luck

View JoeinGa's profile

JoeinGa

3157 posts in 631 days


#13 posted 550 days ago

I did exactly what you’re asking … BUT… I had a small (2hp, 30gal) compressor to start with and I had a chance to get a bigger motor and pump (which I jumped on as it was free). Then I needed more VOLUME so I could paint bigger things (like my truck) so I got (again free) another 30gal tank and daisey-chained it to my existing unit.

The thing is, my 5hp motor/pump unit WILL supply the added capacity to my system. Your small pump/motor wont do what you want it to do. Here’s mine before,


.

And after ..
.

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View cosmicturner's profile

cosmicturner

403 posts in 2019 days


#14 posted 549 days ago

I am by no means an expert but dot you just match your spray gun to the output of your compressor? You just can’t spray the same volume…
Nice set up Joe hope that bad boy accumulator is attached real good.

-- Cosmicturner

View Ken90712's profile

Ken90712

14878 posts in 1813 days


#15 posted 549 days ago

Funny thing about air compressors, I have a good sized on in my shop as I plumed it for both the garage and woodshop with copper piping. I have a buddy with a machine shop who seems to never run out of air. When I looked at his comp, his tank was smaller than mine which surprised me. When I looked at the motor is was a 5hp much stronger than mine so when it kicked on it filled up the tank quickly & recovered quicker with no noticeable lag. Just food for thought. Good luck.

I have the Earlex 5500 and love that as well.

-- Ken, "Everyday above ground is a good day!"

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