This question from Ken is a great example of the sort of query that speaks to the working principles of an air compressor – and one that may seem a little obvious to long time users of air compressors. I love these sorts of questions – they bring out the pure basics of how air compressors work!

by Ken
(Westchester County, NY)

Can I fill a tank style compressor at home, transport it to my garage, which has no electricity, and then release the air without a power source? I can’t use a gas powered compressor.

Portable compressor air tank

Portable compressor air tank
Photo: princessauto.com

I want to use my compressor in my garage which is a distance from my house. The garage has no electricity,

So, can I fill the tank at home, transport it to my garage and use it without any power source? I can’t use a gas powered compressor. I plan to use the compressor to clean tools and parts of my workshop that I can’t get to with a battery operated dustbuster.
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Ken, you sure can.

Once the air compressor fills with air and shuts off on cut out, if you unplug it, all it is now is a tank of compressed air. Move the compressor to where you want air, plug in your blow gun or brad nailer, and away you go.

Depending on the tank size and the tool being used, you might get a good long flow of air, or it may not last long.

One thing you can do to make the air in the tank to last longer is to dial down the regulator setting to 25 PSI or so, just enough pressure to get good blow off. Then your tank will last quite a bit longer.

One other thing you might consider. Acquire a portable tank like the one shown in the photo, and fill it with your compressor. Now moving your air to the point of use will be a lot easier. If the tank hasn’t got a regulator, and most do not, consider adding a small general purpose air regulator onto a nipple from the tank outlet. Then put a coupler on the other side of the regulator, and you can no dial down the air to suit the tool and extend the tank air life.


Add a tank and which compressor is better?

by Ronald Norris
(Altoona, Pa., USA)

DIFFERENCE BETWEEN THE 2 ALSO ADDING TANK

I have a 2.5 hp. 10 gal. compressor. I want to add another tank to it for more air capacity. Is this hard to do also would my motor work with this without any problems, this motor is not cast or at least there is nothing saying that it is (Harbor Freight)

Now my next question, my compressor is 2.5 hp. 10 gal. induction motor. Air delivery is 5.3 scfm @ 90 psi, 6.2 scfm @ 40 psi. working pressure is 125 psi. 3400 rpm horizontal tank. I was looking at one (Harbor Freight) which is 2.5 hp. 21 gal. air delivery is 5.8 scfm @ 40 psi, 4.7 scfm at 90 psi. single capacitor motor, working pressure 1s 125 psi also it is a vertical compressor.

Is there really that much difference in the 2? I can get the vertical compressor at a really good price but I read some 85 reviews on this and it’s about 50/50 % on what people thought and the way it does and doesn’t hold up. It weighs around 100 lbs. and I would have to lug it up 2 flights of stairs, a lot of reviewers said that it work not work after setting it up.

This is why I’m asking about adding another tank to my 10 gal. and asking about the motor being able to work since it doesn’t state cast iron anywhere on it.

thanks
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Hi Ron:

Adding a second tank to an existing compressor to increase the precompressed supply of air for an air tool makes perfect sense.

It is relatively simple to do. Information on that is found linked from the tank section on the sitemap page.

With reference to “would my motor work with this without any problems” it is difficult to give you a specific answer.

Lower cost compressors are not build to last as an industrial type compressor will. So, will you wear out a low cost compressor sooner if you add another tank? Perhaps!

If you are running the pump far longer than it is supposed to be run at one time, the answer is absolutely yes. If you are running it to fill the two tanks incrementally, and the compressor does not overheat in the process, the life expectancy would not change all that much, I would imagine.

See the page on duty cycle for more details on this.

Is there much difference between the two compressors? On what are you basing the answer? If it is capacity, no, not much. If it is the life expectancy of one air compressor over the other, see the paragraph on duty cycle.

In my opinion, all DIY (that means cheap) air compressors are designed to run fairly short periods of time, and not very often. The type of use a typical DIY hobbyist might, running an air tool for 10-15 minutes, or blowing off a work bench and such. If you want a compressor for regulator, daily use, and the compressor is being used to earn money, either buy a better compressor or be prepared to replace the cheap one more often.

Ultimately, the choice is yours.

In my case, looking at the two air compressors you refer to, lugging 100 lbs. up a flight of stairs would make me decide for the lighter compressor right quick.


Getting air into a portable tank?

by jim
(long grove,IL)

I have a Napa 10 gallon portable air compressor tank. The old valve (MVP #4706076) is shot. I bought a Husky SKU#631-048. I have it set up to fit on the tank.

NAPA 10 gallon compressed air tank

NAPA 10 gallon compressed air tank. Photo: napaonline.com

BUT, I need to get air INTO the tank. I need some type of tire valve stem to allow air to be put into the tank at the gas station. Any idea on how I can find a part (valve stem) so I can put air in the tank?
Thanks for the help.
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Well Jim, I would think that an auto parts store would have the valve you need.

I did a search for threaded tire valves, and found some, so you can do the the same. You would thread the tire valve onto a bushing on your tank, and when you connected the garage fill hose, air would flow into the tank. You could monitor the fill pressure on the tank gauge.

If you were filling the air tank with an air compressor, you would simply nipple a ball valve onto the tank, and install a connector onto which you would attach a coupler from an air hose when you wanted to fill the tank. You would open the valve after you connected the hose, watch the gauge to see when the pressure got where you wanted it to be, and then close the valve. Then you would disconnect the coupler, and your tank is full.

You might want to have a look at this, as Jim G. has done essentially what you want.