Adding a tank to my compressor

by William
(El Paso, Texas, USA)

I have a 2.5hp/ 8 gallon tank, 125 max psi. I think the delivery is about 5 CFM. I want to use it for painting but it seems the motor is always running. Adding an extra tank seems like a good idea, but will it help? Is my compressor good enough to use paint guns with?

William, see the section on the site map page under TANKS for all the info you need about adding a tank.

With an extra tank, your compressor will have more pre-compressed air for your paint gun to use when you start spraying, but, if it is as I suspect, your paint gun pulls more air than your compressor can pump, then you'll wait twice as long for the tanks to recharge.

You also have to be concerned about duty cycle on your compressor.

What is the flow demand of your paint gun, and, at what pressure?



Comments for Adding a tank to my compressor

Click here to add your own comments

Mar 01, 2012
The paint gun
by: William

These are the specifications of my paint gun as written:

Operating and max PSI: 50 Psi/ 80 Psi
Air Consumption: 4 CFPM @ 30 Psi
Air inlet: 1/4' - 18 NPS

I do not know the reasoning behind stating the consumption at 30 psi when it can only work above 50 psi.

Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Air Tank Information.

Add an air tank

I read the article on adding an air tank. I am new to this and little scared which may be a good thing.

Where you thread a tee into the new/spare air tank is that where the copper line comes out of the compressor and runs down to tank (vertical setup).

What prevents the pop off valve from popping off. Won't the tank get too much pressure.

Are you running your hose to the tool your using off the spare/new tank? Is there anyway you could draw me an illustration or send me a picture? Thank you for your time and the awesome web site.

Thanks again. Pat

Bill says...

First of all Pat, if you wish to commission me to do work for you, please contact me via the contact page, and I'll be happy to respond giving you details.

Second, when you add your second tank, you simply plumb it from the discharge port of your existing compressor. You don't need to touch the copper feed line from the piston head to the tank.

When your compressor runs, air flows past a check valve into the primary air tank. If you have another tank connected to the discharge port of the compressor, air will continue to be compressed into the first tank, and then out the discharge port to the second tank, until it fills both to the cut out pressure.

Your pressure switch controls the pressure at which the compressor shuts off, and until that tank pressure is reached, the compressor will continue to run and fill both tanks.

You might have an issue with Duty Cycle.

Hope this helps.



Comments for Add an air tank

Click here to add your own comments

May 01, 2011
Add an air tank
by: Anonymous

I'm new to this as well.

It would be helpful to place some pictures or drawings for the connections. It seems to me that your hooking the tank up as serial and not parallel (electronics term).

Is this true, I'm not sure I understand.


Added tanks can be serial or parallel. Good idea about the schematics. Will try to get to that soon.


Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Air Tank Information.

Plumb a storage tank at the start?

Is it acceptible to tee off the beginning of the air supply to machinery and plumb a storage tank ?

We want to install a remote air storage tank at our factory.

The compressed air will go through a dryer before it goes into the tank.

My question is can we just tee off the main air feed into the top of the storage tank?


You want to add a tank. You want to feed the line from the dryer to a tee on top of the tank. You have an "in" to the tee from the dryer, the drop line from the tee goes into the tank, and the other "out" line from the tee goes into the main line to the shop?

Sounds like a perfect solution to adding additional compressed air storage to me.

Make sure you drain that new tank daily, or put an auto drain on it, to be sure any condensation is bled out regularly.

Shouldn't be too much, as the line is coming in from the dryer, but the air will likely still be warm, and as it cools, water will still condense out.



Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Air Tank Information.

Reusing the tank of an old compressor for extra storage

by Hubregt Hogerheijde

The motor of my old Metabo compressor gave up, recently. I'm planning to buy a replacement and want to use the tank of the Metabo for extra storage.
How should I make the correct connections? The Metabo is just the usual hobby-type compressor: one outlet controlled by a manometer, one outlet giving the full pressure. Of course I should fill the tank elsewhere, but where?
I will welcome any advice!

Thanking you in advance,

Huib Hogerheijde

Bill says...

Huib, adding a tank to increase the available pre-pressurized air from an air compressor makes good sense.

When you add a tank, the compressor run time between shut-off will increase, as it is now filling two tanks to cut out pressure each time the compressor cycles, so watch out for the compressor duty cycle. See the duty cycle link under General Information on the site map page for more details, if that will help.

In any case, adding an air tank is generally a good idea, and plumbing it is fairly easy, as well. See the link to Add A Tank under Tanks on the site map page.

Cheers and good luck.


Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Air Tank Information.