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PEX-AL-PEX airline piping

tonycastec

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I need to plumb airline throughout a garage that is 60x30. I have read some of the comments about black iron (rust flakes clog filters/heavy/lots of connectors,difficult to change), copper(expensive ,should be silver soldered?),Sch 80 pvc/ cpvc(shattering/shrapnel problem?)
It seems PEX-AL-PEX a.k.a. PAP is an alternative that is gaining popularity. How does the modern spec. 3/4" PEX-AL-PEX hold up over time? Let's assume no u.v. issues inside the garage. My new compressor is 7.5hp/2 stage//175psi/80gallon, but I shall restrict the pressure in the hardlines after the compressor to no more than 120 p.s.i.I'll be sand blasting.
What is the verdict on PEX-AL-PEX ? Are there alternatives?
Who makes the best tools and brass fittings?
Wrisbo/Upnor , Everhot(decrimper)
Thanks for any constructive ,technically verifiable comments.
 
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CaseyJoes.

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If your serious, black iron is the way to go. It has been the standard for years and once installed (and I mean installed properly) it should last next to forever and not have any problems at all. There is a proper way to install the lines and I would probably buy some sort of book covering all of that if I was planning on installing a setup from scratch in a garage that size.
 

Ajwelds

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Copper, steel pipe(black or galvanized) or Transair. PEX might have the same problem as PVC. It's designed to carry water, not compressed air with oil vapor in it. It's the oil from the compressor that causes pvc pipe to shatter. Their is a PVC that is oil safe but has to be made to resist the type of oil in your application. It's not cheap so it leaves you the other choices.
 

79firebird

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Victoria bc
Use the infloor pex type. it is plastic metal then plastic works fine. ive put it in 15 local shope heere in town and have passed code. I tested it to 200psi to see if there where any leaks for 24 hours. Sp far no probs since if done any. Longest one was done 13 years ago
 

c39er

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I have always heard not to use galvanized because inside the pipe the galvanizing will eventually flake off and cause problems.

Gee, My galvanized water pipe hasn't flaked off in my drinking water on me. I'm still alive after 40 years of drinking the water out of it's galvi coated pipes!
My Shop has 16 year old Galvanized 1" air lines.
I did notice galvanized metal flake occasionally in my paint jobs!:bounce:
 

Bill Crowell

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IMHO, PEX wasn't really such a bad product except that rodents would chew through it during the summer heat in order to get water. That's why most people who had PEX water lines replaced them with copper. If you were to get significant condensation in your air lines, this might be a problem.
 

darkk

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I'm using Pex for my air lines. My whole house is plumbed with it. I had to pressure test the plumbing for inspection. I pumped 135lb air in it and kept it there for 2 weeks until the inspector came by. No problems there. Pex will not fragment like pvc.poly whatever etc. If pex fails, it will only open a split which can be cut out and repaired. They even use a plastic line for air brakes in big trucks. I got no problem using plastic. Look on you tube for some demonstrations with pex tubing. They run it between two gears and really chow it up, heat it almost to melting and it goes right back into shape. And it's cheap and easy to use. I'm not a fan of the shark bite fittings, I use SS crimp fittings.
 

ActAppalled

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I have always heard not to use galvanized because inside the pipe the galvanizing will eventually flake off and cause problems.

This is more of an issue on hydraulic systems. For air use it would be fine. My vote, however, is for black sch 40 pipe. This will last a lifetime, especially with a proper air drier and oiling system.
 

BMEP

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Pex-AL-Pex looks like great stuff but it sure isn't cheap. The site I found has 100' of 3/4" at $241. A 3/4" tee is $46.
 

Falcon67

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Ya - he's talking pex-al-pex, which IIRC is aluminum tube. Great I think for air - not so cheap maybe - 100 meters of 1/2" at Amazon is $100.

What is PEX-AL-PEX:
Tubing consists 1 layer of overlap-welded aluminum core aluminum sandwiched in between of 2 layers of PEX, resulting in a 100% oxygen barrier.

The pipe thing is LOL - one person says black iron rusts and flakes, another says galvanized chips and flakes. I used iron - never any issues. Put in drop legs, drip loops and purge water regularly. And as much as possible capture the water at the compressor. I haven't noted any problems with my iron stuff.
 
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nehog

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Gee, My galvanized water pipe hasn't flaked off in my drinking water on me. I'm still alive after 40 years of drinking the water out of it's galvi coated pipes!

Bet you are not all rusted up either! :lol_hitti

I'm not sure galvanized would offer much of an advantage, but I don't think it will be an issue, either.
 
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tonycastec

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Sadly some of the above posters clearly do not know what PEX-AL-PEX is ,yet adamantly promote traditional airline pipe and (rightly) condemn pvc .I think they mean Sch 40 pvc . Sch 80 may be O.K.(?) but why risk it?

Here is some additional info on sources that I found:

EBay sells 100' of Pex-al-Pex for $75.

You need fewer fittings than if using iron or copper.

Pex supply have fittings at reasonable prices:
http://www.pexsupply.com/Viega-46540-Zero-Lead-Brass-3-4-PEX-Crimp-x-3-4-PEX-Crimp-x-3-4-PEX-Crimp
http://www.pexsupply.com/Mr-Pex-MP857-3-4-PEX-AL-PEX-Compression-Fitting

A good point was made about condensation accumulating in sags on the horizontal lines of pex-al-pex.It might 'burp' out when a tool was in use. In my case it will be laid in the eaves on the edge of the plywood attic floor so there will be no sags between the drop-legs. Without a method of keeping the airline sag-free ,this water problem could be a serious negative.
I hope this is of interest and use to fellow listers.
 

Gregory M

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i had some red and blue pex tubing left over from my house remolding job so i used it in my garage. i hooked it up to my air compressor with a max pressure of 125 lbs and have used it for over a year now with no problems.
 

Suprafied

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A major reason to use aluminum lines over the black iron standard is the less drag that is created by the difference in surface tension. The reduction in surface tension can generate more output at the exit with the same input from your compressor (Ie. maintain higher exit pressure than of the steel equivalent that results in more output in your compressed air tools)

This is reason is more prominent as distance increases from your compressor to the normal work area.

Also, the pex/aluminum setup will install quicker than black iron. Depending on who is doing the install this may result in more labor charges due to the added time.

DP
 
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trboxman

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A major reason to use aluminum lines over the black iron standard is the less drag that is created by the difference in surface tension. The reduction in surface tension can generate more output at the exit with the same input from your compressor (Ie. maintain higher exit pressure than of the steel equivalent that results in more output in your compressed air tools)

This is reason is more prominent as distance increases from your compressor to the normal work area.

Also, the pex/aluminum setup will install quicker than black iron. Depending on who is doing the install this may result in more labor charges due to the added time.

DP

How many CFM are lost due to friction within the iron pipe? Realistically speaking, of course....
 
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tonycastec

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In related posts some contributors mentioned the high cost of "Rapidair" which is a proprietary brand of pex,nylon, pex-al-pex and other airline systems.This was cited as the reason for not liking pex-al-pex. Generic pex-al-pex is significantly cheaper than copper and although more expensive than black iron -don't forget the ease of installation. There is also the issue(reported elsewhere in several GJ posts) of thread leakage from sub-standard chinese black iron and flaking from galvanized pipe.
The solution seems to be to buy the generic pex-al-pex from the suppliers mentioned in posts above in this thread.
Two points of interest from the Rapidair site :
1. Maxair is a cheaper alternative- just pex,but rated for compressed air?
2. Pex-al-Pex does not sag with the recommended clip spacing because of the aluminum core.This eliminates the condensation water-burp concern?
 

Lazerus

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Every industrial building in North America and I'm sure elsewhere uses sched 40 black iron pipe. Installed with pipe sealant (I prefer Teflon tape but others prefer the goo) there is no leaks. Pipe threads are tapered and need more torque than some realize. Unpainted with wet air they last for decades in west coast sawmills. In a home shop I expect they won't have even reached their half life by the time your grand kids sell the place.

Install is more work and takes some time to get it right but produces professional looking results easily. Pex and its variants take a bit of skill to produce trouble free joints and lots of skill to get even close to professional looking results.

There is lots of details to properly set up a shop air system that as a newb to the board I'm not going to spout off on till I lurk way more. But I do want to add a simple solution to the line pressure drop at the end of a long run. A small 1-5 gal tank with a male and female quick connect fitting on it will solve the problem. Run your supply from the compressor (shop air) to the male and a short whip line (5-10 feet depending on what you're doing) to your tool. If you regulate your tool pressures, running high to the pony tank and regulate from that will give you a very capable system with 400' of 1/2" hose running back to the shop. Nice for end of driveway work.
At work we have a 20lb propane tank, valve replaced with a T fitting and couplings. Nice for repairs out in the yard without getting the welding truck and it's gas powered portable compressor. Fixed mounted tanks are stationed at a few of the machine centers that need high volumes of air instantly. in a shop that can be done by up-sizing the pipe at that drop. Run 2" or larger down from your halo to your frl.
 
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tonycastec

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Trying to focus like a laser on the PEX-Al-PEX aspect, the only negatives seem to be:

1. a vague suggestion it isn't neat(?)-yet another confusion of plain old water pipe PEX and Pex-al-Pex?
2. it is more expensive than black iron -but no mention of the time saving installation or the threaded joint leaks with the ubiquitous chinese pipe and fittings.
3. it may dissipate heat at an insufficient rate -so fit an after-cooler?It certainly does not conduct heat at anything like the rate of aluminum pipe because of the pex sandwich layers around the aluminum.This is covered in threads elsewhere on GJ http://garagejournal.com/forum/showthread.php?t=50946&highlight=magnetic+starter&page=2.
 

ishiboo

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How many CFM are lost due to friction within the iron pipe? Realistically speaking, of course....

Agreed. It's irrelevant.

The advantage to using PEX over threaded pipe is by using fewer fittings (especially the short right angles), you will have less pressure drop with high CFM tools, depending on the configuration of the run it could be quite noticeable.

Is PEX-AL-PEX rated for higher pressures than plain PEX? Can you not find plain PEX that meets the pressure requirements? Both split like copper if damaged/burst and do not shatter like PVC, and plain PEX is much cheaper. I know that much of it is not rated for over 125psi though.
 
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tonycastec

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quick/partial burst pressure data for PEX & Pex-AL-Pex:
Generic 3/4"(size is important!) PEX has a burst pressure of about 475 psi but a working pressure rating of about 150psi.
Pex-AL-Pex is 580/362 -so it is a huge and perhaps needless safety margin. I say needless because if your compressor managed to produce enough(over 500psi?) the generic pex just splits open. It does not shatter producing shrapnel like old,brittle,u.v. exposed Sch.40 pvc. rated for irrigation/potable water .
Frankly, U.S. made Sch.80 (yes 80,not 40)cpvc would be fine in the 'right' situation but there is so much paranoia & ignorance there is no point discussing it. For those who want to 'murder' Sch.80 cpvc ,please start your own thread.It is a dead issue.
 

Lazerus

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LOL, no, not even close. Lots of industrial places use copper, aluminum, PEX, and even PVC. :lol_hitti


We seem to have a difference of opinion as to the definition of industrial.

All of the mines, mills, gas plants etc I've ever been in had main supply lines far larger than the "others" allow for. For a 6"+ main it's not only the best choice it's likely the only choice. Point is moot and was poor phrasing on my part. While it may only be in 99% of heavy industrial it's also widely used by most medium to light industrial. Food plants predominantly use SS pipe for obvious reasons.

The point I was making is that all of it's in use down sides (corrosion etc) have proven over time to be minimal for high demand users. And in my opinion non existent for a light duty or home shop. IF the system has been designed correctly in the first place. To that point, the design is fairly easy and should be the same for all material choices.

Instillation; pipe requires 2 specialized tools ( hand threader and pipe cutter). PEX and PAP only require the one? (crimper?) Copper (not legal for air in a work place here) requires 3? (torch, tubing cutter, crocus cloth?). I do very little pvc and as it ranks below rubber air line hanging from nails due to safety I'm not going to look it up.

After that it comes down to skill. If your joints leak even with C.H.Ina corp. products then you didn't use enough sealant or torque. Even dry fit at 150psi tapered pipe tightened properly will not leak. Sched 40 with taped joints and china fittings will hold 2500 psi hydraulics just fine.

PAP is flexable and according to google is often sold in a roll. Thus it requires a good eye and lots of hangers to keep it looking good. And I assume like pex there is no adjustment for fitting angles once it's crimped.

Pipe takes some time to learn how long to make the threads, and what your cut lengths will be to allow for the thread that goes into a fitting. Some prefer their pipe to be set dead level I prefer 1% grade to my low points. I also up and over for the drops off the halo to reduce the water at my frl's. The structural strength of pipe also reduces clamps needed at your drops,

In the past I haven't bothered with a heat exchanger/dryer between compressor and tank or tank to system but my tank has a remote drain (I never have any luck with auto's) and nothing I do currently would care if I had a little moisture in my air. There are several low$$$ options if you do need really dry air.

Either way you need to rent or buy some new hand tools and learn some new skills. A quick look for PEX-Al-PEX crimps are $30-40, a hand threader for pipe is $60+ and a cutter probably $10-20. If you don't have one your going to also need a good tape measure and torpedo level. But that goes for all systems.

People gravitate towards the non threaded options because they seem to be afraid of the threading process. With all the C.H.ina brand tools pushing the price of a hand threaded down to handyman levels there is no good reason not to use it except cost of the pipe. From my limited searching pipe was cheaper than PEX-Al-PEX, and the fittings were way cheaper. That could just be a canadian tax thing tho.
 
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tonycastec

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Thanks for your interesting contribution.
The problem with black iron is that most of the anecdotes relate to USA made pipe and fittings. Those are now difficult to find for a retail buyer. The problems with Chinese pipe and fittings leaking are well documented here on GJ. So even if it WAS an option in the past, it is a risky choice now.You can't tell if the threads on a chinese fitting or pipe will leak by looking at them. Because of this issue ,you'd have to use lots of unions in case of leaks. If you use just fittings in the normal way, you could waste much more time trying to fix leaks. I agree that IF you can get USA made pipe and fittings it is an attractive option if fitting time is not important.
I have all the threading tools for iron pipe so that is not an issue.But threading lots of 3/4" pipe is a significant task.Crimping and decrimping(LOL)is easy and fast.Changes/additions are also easy.
The trick with PEx-al-Pex would be to find the best sourcs for material and tools -any experiences offered?
 

Torque1st

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Thanks for your interesting contribution.
The problem with black iron is that most of the anecdotes relate to USA made pipe and fittings. Those are now difficult to find for a retail buyer. The problems with Chinese pipe and fittings leaking are well documented here on GJ. So even if it WAS an option in the past, it is a risky choice now.You can't tell if the threads on a chinese fitting or pipe will leak by looking at them. Because of this issue ,you'd have to use lots of unions in case of leaks. If you use just fittings in the normal way, you could waste much more time trying to fix leaks. I agree that IF you can get USA made pipe and fittings it is an attractive option if fitting time is not important.
I have all the threading tools for iron pipe so that is not an issue.But threading lots of 3/4" pipe is a significant task.Crimping and decrimping(LOL)is easy and fast.Changes/additions are also easy.
The trick with PEx-al-Pex would be to find the best sourcs for material and tools -any experiences offered?

The Asian pipe and fittings have improved dramatically over the years. I really don't see much of a problem with it anymore. The use of a good pipe dope like Rectorseal#5 removes any remaining leak problems. For most home shop installations threading pipe is not required. Threading is only required when tight locational tolerances must be maintained. With a selection of pre-made ******* at hand threaded pipe installation is fast and easy.

Pex-Al-Pex like any product that uses plastic either alone or in layers does not conduct heat well to cool the air. This is not a problem in small seldom used installations, in dry climates, or in large industrial applications with moisture removal equipment in use. Unfortunately it can be a problem with some medium or heavy use home shop applications in humid environments.
 

Ajwelds

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Lazerus, I'm curios why Canada doesn't allow copper for air. What do plants do for breathing air, control air or instrument air? SS tube & Swagelok fittings?
 

cwlo

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The Viega Fostapex is the preferred choice for PexAlPex. However, you need a reamer as well as the crimper. Basically, the reamer takes off the outer layer of pex+alum for the fitting, so that there is just the layer of pex. You can then use a regular pex fitting, as the OD is now the same as regular pex. They even sell it in straight lengths, although its hard to find.

Chris
 

Falcon67

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I asked a local plumber about sealing Chino pipe since he does it for a living. He said it was a problem but was what it was. He said to wrap the pipe with teflon the number of warps you think is normal, then go 2-3 more. Use a good dope on that and torque it up. Cross fingers, check for leaks. That helped in my install. "2500 PSI" dope only didn't seem to work near as well. As usual with Chino stuff, about 80%+ of the fittings were OK as is. The worst problem was Ts - I had two that were threaded such that the pipe coming out one end had about a 3 degree angle.

In my install, the smaller fittings and ******* are so cheap I used JB weld to set up some complicated taps, like the double T tap I built for splicing in my 10CFM air dryer. No leaks and cheap enough to toss later.

I used unions to break up long runs for service and positioning, also on the up leg of the "up and over" drops. Hard to get 20' of line an 2-3 Ts to all line up pretty.
 
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Torque1st

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Lazerus, I'm curios why Canada doesn't allow copper for air. What do plants do for breathing air, control air or instrument air? SS tube & Swagelok fittings?
I really don't know about Canada.

From my research Copper is not allowed in some places because of fire codes. Probably due to the low melting point of soft solder and the inability of inspectors to tell the difference between that and brazing with a glance.

Breathing air, control air, and instrument air come under different codes because of volume and pressure.

If you start looking into building, safety, and fire codes you will come across sections incorporating 'mechanical' and other codes by reference. Those codes get very specific about materials and processes used. Most people just skip over those references while reading the 'code' and few have actual access to those codes called out by 'reference'. You can buy copies for :shocking:$$$$$ or some technical libraries keep copies.

BTW, I have used a lot of SS tube and swagelock fittings. :beer:
 

Lazerus

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Lazerus, I'm curios why Canada doesn't allow copper for air. What do plants do for breathing air, control air or instrument air? SS tube & Swagelok fittings?

Control and instrument air is predominantly SS, There is a magic pressure under which you could use copper but I'm not sure what it is. 30-50psi would be my guess.
The issue as I understand it is one of quality control and the compress-ability of gasses. Fluids have incredible inertia, so if you do have a worst case failure the shrapnel area is very small. But even at that pressures are limited, usually far under the safety factor of the pipe/tube. There is no reliable way to confirm the strength of a soldered copper joint, add to that the fairly fragile thin wall and you have too many opportunities for someone to get hurt. We don't even allow people to take risks on there own time let alone at work. safety factors of 5x are normal. So a 130psi air system must use 650psi rated components. I know for sure that anything over 100psi is considered high pressure but I'm not sure how far under 100 is still high pressure. The plastic on PEX and PEX-AL-PEX would probably make it safe as all connections have to be mechanical.
There is a goofy plastic line that food plants are in love with but it's only used in small diameters. Same **** that they use on air brakes. On the face of it it's a good product. And if you install it, strap it down, and never mess with it again it's not bad. Look at it sideways and it leaks. That's mostly my opinion tho... Hissing air leaks are my pet peeve. Any time I'm in a new plant with "look busy" time I make it my mission to seek out and fix any air leak I can hear. The sawmill I'm at currently has a bad one right over the work bench in the Millwright shop. The 4" header has a 2" T coming off of it. My 24" pipe wrench isn't enough to tweek the 4". The design was bad, after the T the 4" runs for a full 20' stick and then turns 90* 6' into a remote reservoir strapped to a vibrating deck. The vibrations move the leg off the 90* like a wrench loosening the threads at the T. You should never move from a fixed support to a vibrating support without something to soak up the vibrations.
 

Redtruck42

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The plumbing layout for my shop (which has the compressor in one corner has a pony tank near the ceiling about 2/3 of the way down the run to help keep the pressure up at the end of the run. It will tee into the line.

If this doesn't work out as well as my experience says it will it has a fitting which would also allow a direct connection to the compressor
 

maitman99

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Colleyville TX
Installed Rapid Air in a 1200sq ft shop. 6 outlets, ran the pipe a foot from the ceiling and put tees in for the drops.

Could not be happier, no leaks, easy to modify and much easier to install and in the end less expensive than pipe.
 
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