Multiple air compressors

[Orange65]

I currently have a small noisy oil less compressor that is borderline for my needs. I am considering getting a bigger compressor but was also thinking of just buying a second smaller compressor to parallel with the one I have. I have a "3HP" 30 gallon take sears unit- if I keep it it will go in a room by itself for noise reduction.

What are the pros and cons of a single large versus two smaller compressors? The big advantage to me is that the second small compressor would save me a couple of hundred dollars. Thoughts?

 

[Brad J.]

Those small compressors make a lot of heat and moisture. Plus they are noisy.

Buy a good used 5hp unit from craiglist. Prices are usually good and they are plentiful. Better yet, pick up an old Quincy/Kellogg/Curtis (any name brand) and overhaul it if needed and you have a lifetime compressor.

 

[matt_i]

Stationary and portable would define the needs for me.

If I was running a trim nailer in the house I don't want to drag out 200 feet of air hose to go to the stationary compressor.

 

[NUTTSGT]

have you looked on CL for a decent used larger compressor ? Buy one that fits your needs and don't look back. Sell the smaller one you have now and put those funds towards the "new" one.

This is why guys on here are always giving the advice of buying bigger than what you need right now.

 

[CNGsaves]

OP . . . you're at classic "crossroad" of deciding what to do when you bought a noisy screaming OIL-LESS compressor that was a bad decision. Instead, in the long-term you WILL end up with 2 or more air compressors for particular task.

Your current "compressor" is mobile . . . .which is it's only benefit. However, it's so noisy, it's undesirable > > > > > > SOLUTION > > > > > Sell it !!!

Shop CL for an OIL splash air compressor that will still be mobile. Perfect low cost compressor is 20 gal horizontal compressor from SpeedAire, Craftsman, Campbell Hausfeld, etc. Some older ones are 120v/240v capable and up to 4 HP. You would be well served by compressor like this and likely $100 to $200 on CL. The SpeedAire "paint sprayer" model is very robust compressor and may be all you ever need.

However, if you use air quite often, then you'll progress to NEEDING 2 compressors . . . . . yep, 2 compressors. The 20 gal horizontal will be your mobile compressor, and you'll want STATIONARY 5 HP 60 gal compressor for your large air needs. Again, look on CL for a bargain as there really is no need to buy a brand new compressor. Belt-driven OIL lubricated compressor will last lifetime for normal homeowner use.

 

[sberry]

Get 1 good one.

 

[Norcal]

Best use of a oil less compressor is to set it up in a cemetery to raise the dead.


Buy a good compressor, a saying comes to mind: "Buy Well Buy Once".

 

[Falcon67]

The best portable I've had - still have - was a 25 gallon Porter-Cable unit, compressor/motor separate. Not very loud, plenty of air, easy to move. I replaced it with a 60 gallon fixed and lines but I keep it in the shed for portable work around the house. I painted two cars with that portable and built the current shop using it. I've had it about 15 years.

 

[turbowoodworker]

I have a plumbed stationary 60 gal for the shop. Powers everything I need.
But I just bought a HF cheapo portable for my trim nailer for a single project in the house. I look at it as being disposable. However, while building my shed, I used the cheapo to power my framing nailer. It was slow to refill but worked ok for my speed. The other alternative was to run a hose out my shops back window.
To answer the OP question, get a real shop compressor if you use the compressor for anything more than blowing off dirt. Save the little one for portability.

 

[Falcon67]

The pancake compressor I bought from HF to do the final remodel on the old house lasted exactly 30 days. The Porter was out on loan. Waste of $$. And, that pancake was so loud you had to wear muffs.

 

[theoldwizard1]

I have a "3HP" 30 gallon take sears unit- if I keep it it will go in a room by itself for noise reduction.

What are the pros and cons of a single large versus two smaller compressors? The big advantage to me is that the second small compressor would save me a couple of hundred dollars. Thoughts?

If that is an "oil-less" compressor, it probably won't have a long life. (My oil-lubed 2 HP Craftsman is over 30 years old.)

When it dies, replace it with a California Air motor/pump. Quiet and their 2 HP will likely put ot more air that your current 3 HP (6.40 CFM at 40 PSI & 5.30 CFM at 90 PSI)..

 

[sberry]

Real stationaries are so cheap anymore and last so long and work so well they are a great investment. This is a do it once kind of thing and not be underpowered forever. I get a hose if I can, portables have their place but not so good for garage and cobbling them together.
Not that it cant be done, it just loses some edge in simplicity and practicality.

 

[theoldwizard1]

However, if you use air quite often, then you'll progress to NEEDING 2 compressors . . . . . yep, 2 compressors. The 20 gal horizontal will be your mobile compressor, and you'll want STATIONARY 5 HP 60 gal compressor for your large air needs.

AGREE !

I bought a 2 HP California Air portable. I have not used it a lot, but boy is it quiet. It should have enough power for most impact wrenches. (5.3 SCFM @ 90 PSI, 125 PSI max)

My "big" compressor is an old oil-lubed 2 HP Craftsman. No, it is NOT big enough for sand blasting or grinding. It will run my cheap cut off wheel for about 60 seconds before it runs out of air. Good enough for what I do, but yes, I would love a 5 HP 60 gallon upright !

 

[BOOT]

I have used the same 60 gal 11cfm craftsmen for almost 20yrs until it broke this fall, then I got a home depot 33 gal 5cfm husky to get me by until I fix it or buy another larger compressor. I was planning on buying a portable for odd jobs that a few hoses couldn't reach or to take places anyway. I think it works almost as good as my craftsmen, but who knows if the craftsmen had declined some over the years cfm wise. idk what stores you got around you but a decent 60 gal at a local farm supply store was better priced than a lot of other big name places, bout $450-500 for a 60 gal 13cfm at a few places round here. I am sure my craftsmen cost more, but I won't buy anything but hand tools from them these days.

 

[Kaizen]

If I'm reading the question right one thing to consider is how to successfully combine two small compressors. You'll need connectors and back flow valves and even then I'm not sure it will work well. I made an attempt at this to connect my ten gallon to my 60 gal stationary as my big one doesn't keep up with a da sander so I wanted to give it some more oomph. the prices on the backflow preventer for air stopped that idea. that might guide you to getting a big one. remember to add a couple hundred bucks to whatever you are looking at for air filter/drier/shut off and maybe pressure dial. oh and a 240 connection.

 

[Orange65]

The compressors would be hooked together to effectively make one larger compressor. They would be fixed in the garage- I have no need for a mobile version. I have owned this one for around 16 years and it still works ok. I don't use an air compressor very often- maybe 10 times a year, but right now I am restoring an old truck so I am going to need air for a sand blaster- maybe 11 SCFM at 40 psi is what I am thinking. I have painted with this compressor and it worked ok, so no problem there.

Looking on Craigslist locally I found one decent priced one- they are all pancake versions or industrial versions.

 

[KDXSR5]

If I'm reading the question right one thing to consider is how to successfully combine two small compressors. You'll need connectors and back flow valves and even then I'm not sure it will work well. I made an attempt at this to connect my ten gallon to my 60 gal stationary as my big one doesn't keep up with a da sander so I wanted to give it some more oomph. the prices on the backflow preventer for air stopped that idea. that might guide you to getting a big one. remember to add a couple hundred bucks to whatever you are looking at for air filter/drier/shut off and maybe pressure dial. oh and a 240 connection.

Why is the back flow preventer needed? If a tank is at, let's say, 120 psi, then the compressor head has 120 psi pushing back on it when not running. This doesn't change no matter how many heads you have. I could plumb 50 heads to one tank, and they would all have the same 120 psi pushing back. What am I missing here?

I was thinking about plumbing two compressors together in the near future to a single tank. If I do, I will wire them so that they come on and shut off at the same time based on the larger compressor's controls using a contactor or relay of some sort to control the smaller compressor's power. Will this not work?

 

[Kaizen]

Why is the back flow preventer needed? If a tank is at, let's say, 120 psi, then the compressor head has 120 psi pushing back on it when not running. This doesn't change no matter how many heads you have. I could plumb 50 heads to one tank, and they would all have the same 120 psi pushing back. What am I missing here?

I was thinking about plumbing two compressors together in the near future to a single tank. If I do, I will wire them so that they come on and shut off at the same time based on the larger compressor's controls using a contactor or relay of some sort to control the smaller compressor's power. Will this not work?

if you wire it to light up off the one then maybe. my 10 gallon had an auto shut off like 15 above what I set it at and my 60 was like 20. so the 60 would keep going and the small tank would over pressurize. as I had them individually running the little one would shut off when I really wanted them both going to the same point. so I had figured if I had a backflow preventer on them then they would run on their own program and not affect each other. you'll probably have better luck with the wiring. I wanted to keep my portable still portable

 

[Kaizen]

The compressors would be hooked together to effectively make one larger compressor. They would be fixed in the garage- I have no need for a mobile version. I have owned this one for around 16 years and it still works ok. I don't use an air compressor very often- maybe 10 times a year, but right now I am restoring an old truck so I am going to need air for a sand blaster- maybe 11 SCFM at 40 psi is what I am thinking. I have painted with this compressor and it worked ok, so no problem there.

Looking on Craigslist locally I found one decent priced one- they are all pancake versions or industrial versions.

if you're hoping to use a pressure pot this won't be enough. I have one and my 60 gallon at 90psi running like 12cfm only keeps up for ten minutes. I only used it for frame blasting. also there will be way too much water in the lines so you'll have to get a drier set up. others I'm sure will concur. I learned this lesson the hard way.

 

[Denwood]

I've been doing this for the last five years or so with a 20 and 60 gallon..both 110V. There is no back flow device in place...nor would I want one for this setup.

When the compressors were in the shop, this was the setup:

Now they live outside in a shed, so all you see is this:

I spent a few minutes adjusting the controls on both compressors so they kick in at more or less the same pressure. During moderate to heavy use, both will cycle, and under light use, typically one only.

I wanted one decent compressor as a roll-away when needed, hence the two.

 

[kv501]

The pancake compressor I bought from HF to do the final remodel on the old house lasted exactly 30 days. The Porter was out on loan. Waste of $$. And, that pancake was so loud you had to wear muffs.

I'd be lost without my pancake. It's a Bostitch, but I've done 7 roofs with it that I can remember, framed and sheeted 3 garages (one was 18 x 52), and driven thousands and thousands of finish nails with it. Never had a hiccup and it's still going like crazy.

I do have a bigger stand up for air tools, etc. but I use my pancake 90% of the time.

And you are right. It's LOUD.

 

[KDXSR5]

if you wire it to light up off the one then maybe. my 10 gallon had an auto shut off like 15 above what I set it at and my 60 was like 20. so the 60 would keep going and the small tank would over pressurize. as I had them individually running the little one would shut off when I really wanted them both going to the same point. so I had figured if I had a backflow preventer on them then they would run on their own program and not affect each other. you'll probably have better luck with the wiring. I wanted to keep my portable still portable

Another option I thought of is setting one compressor to kick on at 140 psi and the other to kick on at 120 psi. This way the only time the second compressor would kick on is if I was using some serious air. This would require some trial and error, but I think it would be doable and could easily be made to run each compressor standalone if desired. Once you know what parts and settings you need to operate the system the way you want when in dual mode, it would be easy to swap from dual setup to single setups.

 

[Kaizen]

Another option I thought of is setting one compressor to kick on at 140 psi and the other to kick on at 120 psi. This way the only time the second compressor would kick on is if I was using some serious air. This would require some trial and error, but I think it would be doable and could easily be made to run each compressor standalone if desired. Once you know what parts and settings you need to operate the system the way you want when in dual mode, it would be easy to swap from dual setup to single setups.

this is what I tried. the big one to kick on and then the little one. couldn't get the little one to kick on as my big one would always be above the minimum of the little one. its a sound theory I just didn't have any luck. Dent has it working above. i'll have to look at my set up again. it was last year. it might have been I couldn't adjust the high shut off so the little one was always just being filled not turning on. hmmm

 

[Denwood]

This will depend on your compressor pressure switch. I was able to set mine up no problem. If I recall correctly, my pressure switch had only cut-in pressure, no differential adjustment. You can set this with the compressors unplugged..drain each until you hear the relay click. This link is a good start in terms of setting them up. http://www.air-compressor-guide.com...switch/air-compressor-pressure-switch-setting

this is what I tried. the big one to kick on and then the little one. couldn't get the little one to kick on as my big one would always be above the minimum of the little one. its a sound theory I just didn't have any luck. Dent has it working above. i'll have to look at my set up again. it was last year. it might have been I couldn't adjust the high shut off so the little one was always just being filled not turning on. hmmm

 

[KDXSR5]

One can always buy different pressure switches to meet their needs as well. We are not necessarily stuck with what the factory supplied when making these custom setups.

 

[sberry]

Now we are buying extra parts and engineering again. The man said he doesnt have use of a portable, this screams trade up for a single piece, single circuit, one machine to maintain with a simple hook up.
I do use 2 but rely on one, one is a back up and could b turned on to meet hi demand. All this is easy and practical for me, second unit was given to me. In a common home garage wouldn't do it.

 

[Kaizen]

Now we are buying extra parts and engineering again. The man said he doesnt have use of a portable, this screams trade up for a single piece, single circuit, one machine to maintain with a simple hook up.
I do use 2 but rely on one, one is a back up and could b turned on to meet hi demand. All this is easy and practical for me, second unit was given to me. In a common home garage wouldn't do it.

sorry my fault...but I learned today too. tomorrow i'll be in the paper after my compressor blows up. lol. either way I'm waiting for more info from the op on sand blasting because that takes tons of air

 

[sberry]

this is what I tried. the big one to kick on and then the little one. couldn't get the little one to kick on as my big one would always be above the minimum of the little one. its a sound theory I just didn't have any luck. Dent has it working above. i'll have to look at my set up again. it was last year. it might have been I couldn't adjust the high shut off so the little one was always just being filled not turning on. hmmm

I have the slave pressure cut in just below the primary. It never runs unless the demand is hi,,,, (and I turn the breaker on) but it does use its tank, yes it fills from the main comp. Main behind sound blanket.

 

[CompressorPros.com]

If you are limited to 115 volts, then maybe two portable air compressors makes sense to get a little more air. If you can hook up to 230Volt, then you can get something more substantial that should last. BelAire makes a unique 2HP 60gallon air compressor that can either be 115 or 230 Volt. It makes really good air for a 115 volt machine (7.1 @ 100 psi). I'll link to a few machines that may be a good option for you.

http://www.compressorpros.com/air-compressor/60-gallon/single-stage/belaire-2061v/

http://www.compressorpros.com/air-compressor/single-stage/60-gallon/belaire-6061v/

http://www.compressorpros.com/air-compressor/two-stage/60-gallon/belaire-216v/

 

[sberry]

This is a good place to invest up in the world of tools. As we know I don't think most would realize the difference between HF and the best in some cases but size matters and with welders and compressors one hits a ceiling pretty fast.
There is just only so much going to come out of that circuit. easy to make it 2x as good or better by using a special circuit and like the 211 welder, gives it enough punch to do chores.
No pain in *** breaker trips, worlds simplest and best circuit, lasts a long time cause you aint running the **** out of it. Hooking up more complicated systems is fine for some guys but I favor one decent size unit. Buy a breaker, buy a wire, leave the existing general circuits for general stuff.

 

[aka Larry]

Another GJ member said it best in another post, something to the effect of "Take your 110V oil-less compressor to your neighbors back yard, dig a 6 foot deep hole, cover it up, and you'll still the damn thing running back at your house".

If there is ANY WAY POSSIBLE, get a 60 gallon 220V unit and never look back. I bought mine from HD and caught it on sale for $399. It's been worth every penny!

 

[sberry]

Whats the fascination with all the sandblasting anyway? Everyone rebuilding old junk or want to? I just removed a small cab from my shop yesterday, havnt used it but once since I put it in 20 yrs ago.
I see a couple Tv shows where they blast everything in sight but you got to have a passion, it gets old fast.
Horse trading being what it is would definitely try to shop, buy sell for stuff in decent shape.
While Jack Olsons garage is not for me where I live for him its about perfect, lets him do the service and hobby things he wants without clogging it up with stuff he really doesn't need. I think the realistic outcome is a long way off if a guy uses 120 comp in the same sentence as sandblasting.

 

[Denwood]

The extra compressor makes a difference more for air sanding with a DA, wet sanding (doing color sanding) with a palm orbital...and sand blasting. Any rust work, I sandblast outside my shop in our back lane as it's the most effective. My two compressor setup pulls about 30 amps at 110V, and delivers ~12cfm@90psi. My garage feed is max'd at 40 amps. It's still not enough for continuous sandblasting, but usable. The 20 gallon takes 20 seconds to disengage from the setup when I need it to. When doing automotive painting, the extra compressor gives some peace of mind not only with respect to the nozzle pressure, but also for redundancy if in the midst of a job.

So if you're starting from zero, an 80 gallon at 220V@15 amps makes sense. If you already have a decent 110V unit, adding another to your system might make sense.

If you're just looking to do occasional blasting then just being patient and waiting for the air is very affordable

 

[LS6 Tommy]

I have a Creaftsman "5" hp 30 gallon horizontal tank I got for free 12 years ago. I've been telling myself I'll get a nice little Quincy when the teflon piston rings finally vaporize. Damn thing runs flawlessly...

Buy once. Buy a nice belt drive pressure lubed unit.

Tommy

 

[LifeLongWNYer]

My Home Depot is great for quick, easy jobs, like airing a flat tire on a vehicle that I don't have enough hose to reach, or for blowing out that hose bid that won't drain by itself, but I realize that it is a short lived machine and worth what I pad for it....not much.

I'm just trying to figure out what to use the tank for when the compressor tosses its' cookies.



JBP


.

 

[sberry]

I agree some wait is affordable. With most of these setups there would be some wait for hard work. I am kind of a fan of some of these air comps, they are not for me but for many they are ideal and affordable.

 

[sberry]

I have done a lot of jobs with 3 hp and one gets used to it. I eluded to some of the sizing in the other thread with the calculators. Knowing if is 7.1 or 7.3 is rather irrelevant in the user world. The whole process is inefficient and the demand margins are much more broad.
Tanks help some, 2 stage really gives the headroom but 2 hp is too small, 3 is marginal and 4 adequate. This is for 1 man doing body and paint. I am sure we can find someone who dunnit with less but these are simple guides that fall in a general ballpark. These are real, somewhat conservative giving the edge to some losses.

 

[sberry]

Buy a nice belt drive pressure lubed unit.

The economy air comps are not pressure lubed.

 

[LS6 Tommy]

The economy air comps are not pressure lubed.

I didn't say economy. I said nice.

Tommy

 

[Richard D]

Step 1: Get a used Quincy and rebuild it if you have to.
Step 2: Never need another compressor again.