Compressed Air in the Shop

[Dwain Lambrigger]

OK,

I have written recently about building Norm's mitre bench and storage bench on one wall of my one car garage "shop." I figured that before I started that job, I should run electric and air. My FIL is an electrician, so I have most of that covered.

This call is about the compressed air. I have 3HP 15 gallon compressor that is about three years old, and I want to run three or four outlets along the bench, then have two hanging reels from the ceiling. I don't think I will need anything more than that.

Here is the rub. I have never done anything like this before. I was planning on useing copper, as I don't have a lot to run, but I don't know anything else.

Where do I start?
Is there a good reference out there?
Do I have a good enough compressor to make this happen?
What size pipe to I use?
What about an outlet to take care of condensation?

Any and all advise is greatly appreciated.

Thanks for your time.

[Dwain Lambrigger]

All,

I am going to install a new workbench along a wall in my shop, but figured before that, I should run some air, as it will never be easier. I have never done anything like that before, so I was going to send out a note asking for advice. I don't even know what to ask, so here are some questions for starters:

1) I am going to use copper, should I consider anything else?
2) Are they any plans out there to start?
3) I am using a 3HP, 15 gallon AC, but I am only working in a one car garage. Is this big enough?
4) I was looking to run four or five outlets, and two from the ceiling with hose reels for the larger equipment. Should I consider any more?
5) What about the condensation? What do I add to take care of that.
6) Is the compressor always running? I was looking to put it into a cabinet, with the door almost always closed.

Any help would be greatly appreciated. Thanks!

Dwain

[Larry Browning]

Dwain,
There are several very good existing threads about this subject which will answer all of your questions and many more that you have not even thought about. Do a search on "air lines" or "compressed in the shop". Try several variations of that and I know you will find all sorts of info. That's what I did.

[Chuck Saunders]

Here are the basics
Connect the compressor to the copper with a section of hose

3/4" copper will work very well.

Condensation is best dealt with by sloping the piping back to the compressor

Provide a stub trap with a valve at the bottom of all vertical runs

Have some ball valve shut offs to isolate the lines (for when the fitting tears off and you have a whipping snake of an air hose)

Bigger piping is better but cost is higher

If you are going to paint, do not install an inline oiler

A regulator at each station is a worthwhile addition as are water separators

[Julian Wong]

Reply in blue

All,

1) I am going to use copper, should I consider anything else?
Like others have mentioned, you should have the main line slope back to the compressor. What I did is to have it sloping back and have a drop stub with a relief valve right after the compressor so that all that moisture does not have to drain back into the tank.

2) Are they any plans out there to start?

3) I am using a 3HP, 15 gallon AC, but I am only working in a one car garage. Is this big enough?
Yes definitely big enough to power all nailers, some air tools like impact werenches, and no tools like air sanders.

4) I was looking to run four or five outlets, and two from the ceiling with hose reels for the larger equipment. Should I consider any more?
2 reels from the ceiling of a 1 car garage is plenty. Plus your outlets from the bench, it's more than enough.

5) What about the condensation? What do I add to take care of that.
What I did is to have it sloping back and have a drop stub with a relief valve right after the compressor so that all that moisture does not have to drain back into the tank.

6) Is the compressor always running? I was looking to put it into a cabinet, with the door almost always closed.
Depends on how much air your tools need, it may need to cycle more. If you're spraying, it will cycle on more often.You can put it in a cabinet, but make sure it has enough cool air ciculating to keep the pistons from overheating.

Any help would be greatly appreciated. Thanks!

Dwain

[Jeff Duncan]

Do your homework and install a decent quality piping system. The air compressor size is really not a concern as it's simple to swap out. Of course that's assuming you locate your current compressor in a location big enough to handle a bigger machine. I have a 5hp 60 gal, I hooked it up to a steel pipe system with a short length of hose. The hose keeps vibrations of the compressor from the piping and allows me a very quick way to swap in a new unit should this one become too small.
As far as number of connectors usually one or two is more than adequate for a location. In normal use you have a single hose with a disconnect and swap tools out. Having four at your bench is probably excessive unless you have a specific reason for it. The most connectors I have in one place in my system is 3, and 2 are dedicated to machines.
Lastly as far as putting the compressor in a cabinet it can certainly be done. Things to keep in mind, it is an air compressor, and to compress air it needs access to an awful lot of it. In short you have to have a fairly large opening somewhere in the cabinet so the compressor has uninterrupted airflow. As previously said you also need enough ventilation to keep it from overheating. I suggest a closet over a cabinet. Then you can cut a hole and mount a furnace filter in the wall or on the door. This will allow plenty of air flow and ventilation while keeping most of the dust out.
good luck,
JeffD

[Larry Fox]

This link was provided to me by Jeff Jewitt when I was discussing piping mine in as I wanted to make sure whatever setup I went with would be able to spray effectively.

http://www.tptools.com/StaticText/airline-piping-diagram.pdf

I went with 3/4" pipe and fittings and MAN was it expensive. With the benefit of hindsight I think that I could ahve gotten away with 1/2". I have a lot of slope to mine - probably about 1/2" per foot and I installed 3 outlets. I don't have a staightforward way to get the water back to the compressor so I put drip-legs at each outlet. Works great so-far.

[Wayne Cannon]

Ok. I understand the article's recommendation against PVC, as it can explode with plastic shrapnel. Why, however, the recommendation against copper in favor of black iron pipe?

[Randal Stevenson]

Ok. I understand the article's recommendation against PVC, as it can explode with plastic shrapnel. Why, however, the recommendation against copper in favor of black iron pipe?

You can google the copper handbook. It says that copper for air, must be brazed, as compared to solder. However there are newer, higher pressure solders available now that people use.
I still prefer black iron for a couple of reasons: 1. Costs less (if a lot) 2. can be fairly easily adapted, as compared to the copper.

[Rich Engelhardt]

Hello,
Copper can also be damaged a lot easier than black pipe.

Anyhow - as far as the 4 outlets - Harbor Freight has an inexpensive two outlet Aluminum manifold. I picked one up and it works very well - which is more than I can say for their quick connects (don't waste time/money on them - they leak - same goes for the borg ones (@ least the ones Lowes has).

[Peter Quinn]

Not an expert but most shops I've seen use copper with out issue. A well soldered copper system can handle hundreds of pounds of pressure and it allows the air to cool faster and lose condensation more rapidly in a small shop environment. Copper transfers heat much faster than iron. Copper fittings also create a little less turbulence at intersections than steel, which may not be of any concern in a small system any way.

Also, pipe should slope AWAY from the compressor, in the direction of the air flow, not back towards it for efficient elimination of water. I was told to use 1/2" minimum up to 75" total run, 3/4" beyond that. Keep in mind that your compressor will run a while to fill the system with air, but once full the pipe will act as additional storage, not additional demand, so a 75' loop of 3/4" pipe will actually increase your systems storage capacity beyond the 30 gallons of the tank itself. Bigger may be better and allows room to grow in the future.

Here's another link with a fairly good explanation of the facts as one expert sees them. I have found companies that do this professionally piping systems in iron (which rusts by the way), copper, stainless, and special aluminum tubes all at costs which exceed my personal budget.

http://www.oldsmobility.com/air-compressor-piping.htm

[Faust M. Ruggiero]

Dwain,
1/2" copper pipe is a good choice. You must use the rigid pipe not the flexible type. Copper pipe is sold with a letter value rating the pressure it can take. It is always best to run a loop from and back to the compressor. If you pitch back to the compressor, the most common method, you can even install a bleeder that will open a drain on the bottom of your tank on a timed cycle and drain the water. Pipe the drain outside. At each location of a 'drop" aim your tee or elbow up, not down. Attach a short piece of tubing then elbow over and finally down. Install a 1/2" ball valve at each drop then your quick disconnect. I never shut down my compressor I merely close the valves since quick disconnects and hose reels leak. I usually tee out to the connection point then continue down to another valve and blow off drain.
Faust Ruggiero

[Jack Vines]

In deciding where to locate the compressor, look long and hard to find a place OUTSIDE your work area. For a small compressor, buy a pre-cast concrete slab, some post footings, build a shed over it which matches your garage and you'll be much happier. Having a compressor cycling right under your workbench is a distraction and is fatiguing. Putting it outside, it runs cooler, the shop is quieter and you haven't used up floor space you need for a tool or lumber which has to be inside.

thnx, jack vines

[Bruce Wrenn]

Slope the lines away from the compressor, with a drain at the far end. When they are sloped towards the compressor, every time you use air, you pull the same moisture up the pipes. Do take offs from the top of the pipe, as to prevent moisture from entering drops. Use LA-CO brand solder flux. It is self cleaning, so you can forget the emery cloth. As soon as the heat hits joints, they become bright. Plumbing supply houses will have the LA-CO Flux. A Bernz-O-Matic trigger start torch provides just the right amount of flame. If you buy Ace Hardware's version, they have a lifetime satisfaction warranty. (I'm on my fourth one, but I have had a plumbers licensee for twenty years.) Propane will do everything you need, so don't buy the MAPP gas torch. Assemblies can be made up on the bench, and then installed. I usually make up my drop, and a couple feet of pipe on each side. This way, up on the wall, I only have to solder two straight couplings. Keep a spray bottle handy. Any where you are going to make a joint, wet down the adjoining surfaces before and after sweating the joint. The lightest weight 1/2" copper will do everything you need. Buy and use one of those heat resistant blankets. Practice sweating a few joints before doing the "real thing."