copper vs pvc compressor lines?

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From your compressor you should have metal pipe( I prefer copper) sloped upwards to a filter and primary regulator. 20 feet is optimum, you can zig zag it if necessary.
This allows moisture from the compressed air to condense and run back to the compressor tank where it can be drained. I have used this setup in several auto paint shops and have never had to install a receiver drier to eliminate moisture at my sprayguns
 
Black iron pipe over copper definitely. PVC No Way! In some areas copper pipe is not allowed for compressed air due to codes. The copper pipe joints are sweated together & therfore the pressure rating cannot be guaranteed. Yes copper pipe is rated at a few hundred psi, but the solder joints are the weakest link. Black pipe isn't that hard to work with & can be cut & rethreaded to make any length you need. It's also cheaper than copper too.
Good luck with your project.
 
I have had 3/4" PVC in my shop for ten years with zero problems running 175 PSI.
 
Lonewolf3165 said:
Black iron pipe over copper definitely. In some areas copper pipe is not allowed for compressed air due to codes. The copper pipe joints are sweated together & therfore the pressure rating cannot be guaranteed. Yes copper pipe is rated at a few hundred psi, but the solder joints are the weakest link. .
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If you are concerned about copper, look to AC units. What do the "modern" refrigerants run for head pressure? Way over 200 psi, that's what.

If you are concerned about sweated joints, braze them like we do in the HVAC industry...........a product commonly called silfos

I'm not necessarily promoting copper over black
 
I worked in a machine shop that used PVC. Every once in a while you would hear a pop and an air leak. I glued many a joint back together when I was there. I never saw shards just chunks that fell on the floor. Maybe it was because we were in an air conditioned shop? If I remember correctly the pressure was maintained at 80 psi in the shop.
 
I havent got mine setup the way I would really like, but right after compressor I ran a plastic coiled air line before my regulator. It straightens to approx 20-25 feet and like above said gives air a chance to cool down and condense before hitting seperators. I would NOT be using PVC.
 
I always used galvanized pipe to prevent any rust from occurring inside the lines. That is what Mercruiser (Mercury Marine) used when I worked there and it never caused an issue even on the paint lines. Is there an advantage using black iron especially in a high humidity area of the country?
 
67Dart273 said:
If you are concerned about copper, look to AC units. What do the "modern" refrigerants run for head pressure? Way over 200 psi, that's what.

If you are concerned about sweated joints, braze them like we do in the HVAC industry...........a product commonly called silfos

I'm not necessarily promoting copper over black
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They silver solder the joints in ac apps.
 
I actually use Teflon lines in my profession (Air poluttion monitoring) 1/4, 3/8 and 1/2 inch. That's what I plan on using, very tough stuff and it's free because I have it on hand.
 
Oklacarcollecto said:
Never PVC... I had a friend that had a line blow up and drove a piece of it through his eye and in to his head. He lost the eye and spent a long time in the hospital. The 600psi is a water pressure rating and water just shoots a stream instead of shrapnel going everywhere.

I run 3/4 galvanized iron pipe.
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Since water is basically non-compressible, a high pressure water line will bleed to zero pressure with a very small amount of fluid release. Compressed air, on the other hand, has a tremendous amount of stored energy, and will take a long time to go to zero pressure if a leak/hole develops.

That is why water is used to test piping systems to ensure the integrity of the system instead of air.
 
I would say PVC is capable of the pressure, but is not a good choice due to the weakness of the material to external forces such as someone leaning on it or hitting it with something.

Just to easy to break it.
 
daredevil said:
They silver solder the joints in ac apps.
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"Silfos" is not exactly "silver solder," and the use of the term is somewhat mis--used over the years because of the fairly recent introduction of LOW temp silver BEARING solder being used in plumbing.

"Silver solder" in the case of AC/ refrigeration should probably be called "silver braze"

"Silver solder" in present form is usually low temp, IE water lines, not what we want here

"Silfos" is a brand name but is DIFFERENT than hi- temp silver braze / solder

"Silfos" or similar material is a very interesting silver bearing rod which can braze copper to copper with no flux. You just clean the copper, heat with oxy/ acet to temp, and flow the rod. It is truely marvelous stuff.

I used to work in this field and am well acquainted with it.

Only time I used actual hi temp silver solder / braze was to connect copper to steel, IE replacing compressors.

There were SOME PEOPLE that used low temp (back then lead) solder to connect AC piping, and in one case I had to go clear through several systems that had been done that way and rework all the joints because they were starting to corrode and leak. These were odd--ball Trane computer room systems which had the compressors in the ID units with only the condenser coil and fans sitting OD. This means that one line going out is not only high pressure, but it's also very hot, as it's the "hot gas" line. I would guess these are more subject to failure due to temperature changes.
 
Researched this subject quite a bit due to building a new shop and needing to plumb in a compressed air system. Don't use pvc, period. Many people do and some get away with it, for a while. I have used it in the past but wont do it again. Besides all the previously mentioned reasons, utraviolet light will also break down pvc over time. Sun shining on it continuously through a window, next to a welding area, ect. Never got a good answer to the effects of compressor and tool oils on it over time but it is designed for water not petroleum products. For me copper was best but most expensive, followed by black pipe (corrodes internally), galvi pipe, and pex. All work. Good system design and a quality air/oil separator, especially for paint work, are essential. YMMV.
 
I'm in charge of maintenance for an textile company & have 2 factories in my care. When PVC lets go it explodes with such force that once I found pieces imbedded in drywall 10 feet away. Fortunately noone was around at the time. All PVC pipe was removed.
When residential copper pipe is used, the only issues are accidentially crushing the pipe & joints letting go. No big deal, just make sure there are wall clamps on the secondary side of all joints.
Personally I prefer Sched 40 blk pipe. Like others have said, it can be cut & threaded to any length you want, it's strong [in 33 years I've never seen a pipe burst] & it's cheaper than copper. Just make sure to use teflon tape on the threads.
BTW, if you use filter/regulator/lubricator assemblies with polycarbonate bowls, make sure to have metal cages on them.
 
If you are going 25' or more I would go larger than 1/2" We ran 5/8 plastic air brake line in our shop and runs my 1" impact fine and we use 1/2" air hose.
 
My phone is acting up so I can't qoute it but whoever said that they solder ac lines is going to run into some serious trouble when we switch to 4-10a. Have fun this summer :)
 
Did not read the entire thread so if this has been mentioned sorry for bringing it up again.....what about using PEX tubing? Have it in our "house", had a pipe freeze a few years ago and it did not crack, it apparently just stretched and when it thawed all was fine. So I don't think it would shatter like PVC would.
 
inkjunkie said:
Did not read the entire thread so if this has been mentioned sorry for bringing it up again.....what about using PEX tubing? Have it in our "house", had a pipe freeze a few years ago and it did not crack, it apparently just stretched and when it thawed all was fine. So I don't think it would shatter like PVC would.
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It was mentioned a few times ink, I personally have 0 experience with it but have heard good things from guys running it.

As some have continued to suggest PVC piping I can only again urge against it. Black iron or copper, perhaps the PEX also but not PVC. It can get wacked with something in the shop, it shatters as it gets older it gets more brittle, it's susceptible to heat and cold, searching the web you find guys that say it's just fine... it just hasn't happened yet. Why risk it, yourself or others? If your system is aired up odds are you are working there. Is the literally few bucks savings worth having that thought lingering in you mind?
 
What would be the equivalent to 3/4" PVC in blackiron or galvanized water pipe?
 
You mean size? All same "nominally." that is 3/4 PVC is "same" as 3/4 black. Black / galvanized varies a little in size, and sked 40 vs of course sked 80 is thicker wall, so smaller ID with sked 80

Sked 40 PVC is fairly close to sked 40 black/ galvanized. The "200" stuff is quite a bit thinner.
 
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