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Forum topic by kyngfish posted 03-14-2019 01:54 PM 328 views 0 times favorited 15 replies Add to Favorites Watch
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kyngfish

33 posts in 387 days


03-14-2019 01:54 PM

Hey guys,

I’m shopping around for an upgraded compressor. I have a 20 gallon – 120 PSI 7 CFM compressor that works fine, but as I get into painting different things, furniture, car panels, etc. I find that I need a little more CFM.

Here’s my question. Most CFM is rated at 90 PSI, but most guns need a measure of CFM 40-ish PSI. Usually, if a compressor has 7 90, CFM @ 40 is a bit higher, but in a lot of cases, the specs don’t show that rating.

What I’m trying to figure out, is what is the most cost-effective compressor I can get away with for hobby painting and the occasional large project, that gives me around 12-14 CFM @ 40. Leaning toward this one here:

https://www.globalindustrial.com/p/pneumatics/air-compressors/two-stage-air-compressors/two-stage-belt-drive-air-compressor-40-gallon-5-hp-vertical

I like it because I don’t really want to take up the space a 60 gal does, but I don’t want to pay the several grand the small, powerful ones do. But really, that one has way more CFM than I need, and if there’s something I can get in the 30 gal range, with the CFM I need @ 40 PSI for around 600, that’s where I’d like to be.

Sub-question: has anyone shopped at global industries? Their price on that compressor is $150 below anyone else.


15 replies so far

View wingless's profile

wingless

26 posts in 40 days


#1 posted 03-14-2019 03:19 PM

Compressor looks nice.

When I setup my compressor, I installed an automatic tank water drain, that opens the bottom drain for a minute, once per week. This was a great feature to keep the tank bottom dry.

A refrigerated condensing cooler was added onto the air output. That changed the air from spraying water droplets to not ever spraying water droplets.

There are rubber bushing feet mounts that work to isolate mechanical vibrations from the floor. I used those and I built an open topped “room” surrounding the compressor w/ a door to decrease the audible noise.

View bigblockyeti's profile

bigblockyeti

5491 posts in 2018 days


#2 posted 03-14-2019 03:32 PM

That compressor looks ok. The floor space consumed by that vs. a 60 gallon compressor should be zero, I suspect the 60 gallon would only be taller. The “5hp” motor is an SPL rating meaning in short it’s complete B.S. & likely closer to an actual 2.4hp. In the specs it doesn’t identify at what pressure the 14CFM volume is measured. One of the more concerning things in the specs was that it stated “Pump configurations available are either 2 cylinder V Type or 3 cylinder radial” I read this as it might come equipped with whatever they have laying around and not leaving it up to the person ordering the compressor to spec what they want. I think if you wait for a sale, you’ll likely find a 60 gallon rebranded compressor from Devilbiss or Campbell Hausfeld brand new in the $500-$700 range that should have all the air you should need based on what you’re planning on doing.

-- "Lack of effort will result in failure with amazing predictability" - Me

View GoingUp's profile

GoingUp

32 posts in 545 days


#3 posted 03-14-2019 04:07 PM

https://www.homedepot.com/p/Ingersoll-Rand-Reciprocating-60-Gal-5-HP-Electric-230-Volt-with-Single-Phase-Air-Compressor-SS5L5/202889756

Ingersoll Rand always compares well if you’re looking to spend. Over 18 CFM at both 90 and 40 psi.

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kyngfish

33 posts in 387 days


#4 posted 03-14-2019 04:27 PM


That compressor looks ok. The floor space consumed by that vs. a 60 gallon compressor should be zero, I suspect the 60 gallon would only be taller. .. I think if you wait for a sale, you ll likely find a 60 gallon rebranded compressor from Devilbiss or Campbell Hausfeld brand new in the $500-$700 range that should have all the air you should need based on what you re planning on doing.

Thanks – so that height actually matters due to my cabinetry. And I think the pump configuration is because there are two versions of that compressor, one with 14 CFM at 90 and another with 10 CFM at 90. I can’t get an answer from the company on what the CFM @ 40 is, probably doesn’t bode well.

RE: Devilbiss or CH rebranded compressors, who sells those rebranded, and when/where are the sales?

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Robert

3315 posts in 1778 days


#5 posted 03-14-2019 04:31 PM


https://www.homedepot.com/p/Ingersoll-Rand-Reciprocating-60-Gal-5-HP-Electric-230-Volt-with-Single-Phase-Air-Compressor-SS5L5/202889756

Ingersoll Rand always compares well if you re looking to spend. Over 18 CFM at both 90 and 40 psi.

- GoingUp

This is what I have. I thought it was way too much but they were on sale.

Its not. Wait till you start using air sanders….I’d be a bit concerned about the tank capacity.

-- Everything is a prototype thats why its one of a kind!!

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kyngfish

33 posts in 387 days


#6 posted 03-14-2019 04:36 PM



This is what I have. I thought it was way too much but they were on sale.

Depends on how much it goes on sale – I was mentioning that my price range is really ideally in the 600-700. Does it go on sale often?

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WhyMe

1129 posts in 1859 days


#7 posted 03-14-2019 07:25 PM

I don’t believe that Puma compressor has a SPL listed motor, amps are to high at 230V to be only 2.4HP. The CFM is 14 at 90psi and 12.8 at 175psi.
http://www.pumaairusa.com/products-06.html

View WoodenDreams's profile

WoodenDreams

505 posts in 208 days


#8 posted 03-14-2019 08:42 PM

Stay away from any air compressor that’s rated for less than 150psi., even if you only have a 3 gallon air tank. The outfeed regulator will govern your air pressure to your needs. With 150psi tanks, the air lasts longer before it needs to kick-in to recharge the air pressure. Hence, the compressor doesn’t start back up as much, So you don’t have to listen to the compressors noise as much. Also if you run air tools such as air guns, you’ll have more initial torque till the air compressor kicks back on. OTHERWORDS YOUR ONLY UPGRADE NEEDED, IS CHANGE TO A 150psi COMPRESSOR. Set the regulator to cut off the compressor at 150psi and restart at 120psi, and set your outfeed regulator line to your your air tool spec. I mark with permanent marker on the air tank the operating air specs (min and max) of each of my air tools. This way you can change the outfeed regulator to the tools being used. Having any air compressor with less then 150psi rating is a big mistake.

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ArtMann

1319 posts in 1114 days


#9 posted 03-14-2019 11:13 PM

Puma is not an off brand. I would rather have it than either Devibiss or Campbell Hausfeld.

View OSU55's profile

OSU55

2152 posts in 2287 days


#10 posted 03-15-2019 11:58 AM

I use a CA Technologies CPR-G (stainless-gravity fed) HVLP gun rated to use 11 cfm at 29 psi gun inlet, and run it off a Lowes Kobalt 2 cyl oiled compressor rated 5.3 cfm at 90 psig, 6.2 cfm at 40 psig, 155 psig shut off (30 gal res). When doing a large surface like a dining table I do have to let the compressor catch up a little. I let the compressor shut off before starting the large surface, then take an extra few seconds between gun passes once the compressor starts running. I’m able to get a large surface, say 3’ x 6’, finished no issue. I usually dont need to run the gun above about 22 psig at the gun with thicker waterbased finishes, it atomizes very well. Lesser guns need more pressure to atomize properly and overspray more.

One thing to consider is to slave 2 compressors together. One will run at a lower on/off pressure. Connect the outlet of the lower pressure compressor to the tank of the higher pressure one. Pressure drops enough the lp compr turns on. The tank on my lp compr is rated to 200 psi. I only slave them for big stuff that I rarely do, since the main compressor can almost keep up.

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kyngfish

33 posts in 387 days


#11 posted 03-15-2019 12:18 PM



I use a CA Technologies CPR-G (stainless-gravity fed) HVLP gun rated to use 11 cfm at 29 psi gun inlet…

This is great insight. The devilbiss gun I’m looking at is rated at 9.9 cfm at 23 psi or 14 cfm at 23 psi depending on the air cap. My compressor actually gets up slightly over 7 cfm at 40. My concern isn’t whether the compressor can keep up – there’s enough capacity there for large panels. Just not a whole car. My fear is what happens if I don’t get the right cfm? Does the paint fail to atomize well? Does the paint just need to be thinner?

View OSU55's profile

OSU55

2152 posts in 2287 days


#12 posted 03-15-2019 04:27 PM

You should use a regulator and pressure gauge at the gun. Everything is fine as long as the pressure gauge, downstream of the regulator, says 23 psi with trigger pulled. When it falls below that, you need to stop to let the compressor catch up. To spray with lower gun pressure, thin paint more. Lower gun pressure will use fewer cfm so the compressor is more able to keep up. Each situation is different – sounds like you may be fine. Worst case is you have to wait 10 seconds or some amount of time between passes with the gun. This can potentially affect flow out of the paint – an experienced car painting person could give info on that. I dont think it would be an issue but actual experience is better than my opinion.

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kyngfish

33 posts in 387 days


#13 posted 03-15-2019 07:54 PM


You should use a regulator and pressure gauge at the gun. Everything is fine as long as the pressure gauge, downstream of the regulator, says 23 psi with trigger pulled. When it falls below that, you need to stop to let the compressor catch up.

So my understanding is that PSI is going to be a function of aperture plus the pressure in the tank – and greater CFM means that it’s a wider aperture – and using more air to get the same PSI. But this also requires a better pump and more pressure in the tank. So, you can get 100 PSI out of a pinhole, but it won’t do you any good. So, I’m just wondering what the impacts of having 20% CFM at the PSI that I need to use the gun is….

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TungOil

1143 posts in 793 days


#14 posted 03-16-2019 12:33 AM

The impact is that you can’t spray continuously. You need to pause occasionally to let the compressor catch up. Another option is to add a receiver, which is just an auxiliary air tank. The compressor will run longer to fill both tanks, but you can spray longer before you need to pause. Devilbis also sells a lower CFM hvlp gun that you might consider.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View Kelly's profile

Kelly

2236 posts in 3242 days


#15 posted 03-16-2019 06:48 AM

I just bought a Husky sixty gallon 3 hp from the big box. It pumps out 13 CFM, so I can paint or blast with it. I’m still running the iron pipe, valves, drains and filters and have to add a 240 30 amp circuit for it. It ran $500.00, minus my VA discount, I got it for $450.00, with tax on that.

The Makita it will be replacing pumps out about 7CFM, which is pretty good for a small unit, but the small tanks would require piping in another tank and for blasting (glass etch and wood), more is better, soooo.

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