Need advice on running an air line.

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Ridgerunner
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Need advice on running an air line.

Post by Ridgerunner » Fri Feb 27, 2009 8:30 pm

I've read the above sticky about using PVC in the shop. I have this in place and used it without incident for the last 4 years. I guess I will replace it just to be safe. My question is what is the most economical, yet effective supply line for my application.

Supply: Craftsman 1.5hp compressor generating a maximum of 125 p.s.i.
Line: Pressure regulator and moisture trap between the supply and the line
Usage: Airbrush 15-20 p.s.i., filling tires and blowing away dust from woodworking jobs.

I could use 1/2" I.D. in either black pipe, copper type "L", or copper type "M". I am ignorant as to the differences between the two types of copper pipe and any bearing each might have on my application. The flexibility of copper pipe is desirable considering where I have to run the supply line around existing water and drain lines and floor joists.

Given my above information, what would you recommend?

Appreciate your replies,
Gary Frost

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Bill Shields
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Pipe

Post by Bill Shields » Fri Feb 27, 2009 8:58 pm

Black iron, screwed together is tough to beat cost-wise.

Copper has come down a lot, so you might want to look there.

Any will work and be safe, just go with your heart and your wallet (and available tools to do the job.

Do you have a pipe threader? or a soldering torch?

Ridgerunner
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Post by Ridgerunner » Fri Feb 27, 2009 9:44 pm

Yeah Bill, I have a soldering torch. My local hardware store will cut and thread, without cost, any length of black pipe I need. I was prepared to use black pipe until this evening when I went by Home Depot and found the copper pipe to be considerably cheaper (which really surprised me). Is there any difference between the two copper pipes to justify a higher price for the "L" variety?
Gary

Jose Rivera
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Air lines

Post by Jose Rivera » Fri Feb 27, 2009 10:58 pm

Some time ago there was a thread about plastic lines and the dangers that go with it.

After that I changed to 3/4 copper, best thing!
Not only safe but very nice looking and light.

I could not find that thread.
If someone can find it please post the link, thanks.
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Harold_V
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Post by Harold_V » Fri Feb 27, 2009 11:25 pm

Given a choice, go with the copper. Especially if it's cheaper than iron. Iron pipe has a nasty habit of rusting inside. Once it does, getting clean air is next to impossible. Unless you have some extremely long runs, or a huge air demand, you can get by very niceley with ½" pipe, which is less expensive and nicer to work with.

Copper pipe, L vs M----wall thickness is the only difference. L is heavier, but not needed. The bursting strength of the M is more than adequate for 125 psi, assuming you choose to use it that high.

Be certain to brush the fittings and clean the pipe ends before fluxing and soldering. Get a stainless brush and some abrasive cloth for the purpose.

You can get by with lead free solder quite nicely, but if you'd like a recommendation, Harris's Bridgit is really nice to work with. Some of the lead free solders don't run well. Bridgit does. Use a water soluble flux for easy cleanup after soldering.

Harold

Mike of the North
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Post by Mike of the North » Fri Feb 27, 2009 11:34 pm

Post no. 3 in this thread has pdf of a copper tubing hand book that might help answer your questions.
http://www.garagejournal.com/forum/show ... ght=copper
Mike
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Jose Rivera
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PDF

Post by Jose Rivera » Sat Feb 28, 2009 12:50 am

Mike, thanks for posting that link.

Wonderful stuff !! :D
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Metalman
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Post by Metalman » Sat Feb 28, 2009 6:20 am

I used 1/2" copper, set it up 18 years ago so I don't remember for sure but I'd guess it was the L (heavier wall). Absolutely no problems with the air system. After a quick look at Mike's link it appears the p.s.i. burst limit is plenty high enough with either L or M.
I used a loop about 15" in diameter of the soft bendable type of copper tube from the compressor outlet to the wall where the run started to allow some give from the compressor vibration. From there it goes up to about 8' high and horizontal with a slight pitch downward to two different drops with trap/regulators. That allows the condensation to drain into the traps. IIRC you want at least 10' or so between the compressor and the first drop to a trap/regulator to give the moisture a chance to condense and be caught in the trap. Something like that. There is no doubt a lot of information on the internet about the subject.
Last edited by Metalman on Sat Feb 28, 2009 8:26 am, edited 1 time in total.
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Post by Jay, Idaho » Sat Feb 28, 2009 8:19 am

Got this after a google search on copper pipe:

K, having the heaviest walls, typically used for underground burial.
L, used for most purposes.
M, with the lightest walls, used for drainage and other low-pressure applications. (Some plumbing codes do not permit M.)
Wall thickness varies with nominal size. The resulting inside diameter is always within a few hundredths of an inch of the nominal size.
Temper
Types K and L are available in two tempers:
“drawn temper,” sometimes called “hard” or “rigid,”
“annealed temper,” often called “soft.” Soft pipe is sometimes called “flexible,” but should not be confused with the corrugated pipes for making connections to water heaters.

Ridgerunner
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Post by Ridgerunner » Sat Feb 28, 2009 2:16 pm

Thanks for the information, gentlemen. A great source of help and information as usual. I'm going with the copper - time to go looking for that propane torch.......

Gary
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Frank Ford
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Post by Frank Ford » Sat Feb 28, 2009 2:21 pm

Years ago an old pal showed me how to replumb the air for an entire shop in an afternoon. He simply used regular rubber air hose and barb fittings.

I did mine that way and it's GREAT. Never a leak, and super easy to modify:

Image
Cheers,

Frank Ford

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Steve_in_Mich
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Post by Steve_in_Mich » Sat Feb 28, 2009 2:56 pm

Gary, I ran copper air lines in my shop mostly within the walls, perhaps there would be a helpfull tip in the description of my air system in my shop tour.

My shop tour; http://www.chaski.org/homemachinist/vie ... php?t=2090
Just because you don’t believe it - doesn’t mean it’s not so.

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