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PEX and Shark BIte fittings for LP air?

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PHPaul

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#1
I want to run an air line in my basement, but I don't want the (noisy) compressor down there. The idea is to run a line to an external chuck and charge the system from the compressor in my garage.

I know PEX tubing is rated for air, and I'd really love to use shark bite fittings for the ends. They are not specifically rated for air or gases, but this would be regulated to a max of 50 psig, more likely 25. It's for airbrushing and a mist-coolant system for my lathe and mill.

Anybody tried this?
 

FOMOGO

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#2
I think at that pressure you would be fine. Just size your line for the distance you will be covering. Mike
 

RandyM

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#3
I realize that you are planning on running at lower than rated pressure. But even that is has potential for catastrophe when someone other than you decides to take control of the system. I am sorry, I am not a fan of pressurized plastic pipe. Plastic gets brittle over time and when it lets loose, it blast shrapnel everywhere. Just a warning, you do what you have to do.
 

P. Waller

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#4
Nylon tubing is used in the air break systems of over the road trucks, a majority of industrial machinery incorporating pneumatic control systems use plastic tubing as do machine tools.

It is a well proven technology.
 

markba633csi

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#5
Yep if it's indoors and not blasted by the sun's uv it should be fine
 

tq60

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#6
Have seen pex in commercial shops for air.
Last was service shop for fire fleet.

They make pex for air service so use it.

Never a fan of the slide on fittings as we prefer the crimp type.



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keebie1984

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#7
Yep if it's indoors and not blasted by the sun's uv it should be fine
If exposed to uv....always choose black.

I work in industrial oil and gas And we use “polyflow tubing” for pressures up to 150 all day long air or gas or liquid it doesn’t matter.

Oh and it doesn’t shrapnel it’s much more flexible than hard pex...it is nylon based.

Buy you a short roll of 3/8” polyflow from a supply company and get a handful of swedgelock fittings (the ones you need) they last longer than diamonds on land.

-greyghost


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juiceclone

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#8
been running 3/8 "equivalent" pex air line at 125 psi for 7-8 years now w gator-bite type fittings. ... keep all pex out of sunlight
 

derf

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#9
My whole shop has been re-plumbed with pex and all shark bite fittings. It runs 175 psi line pressure and I have had zero problems for the last 10 years.
 

jdedmon91

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#10
I like PEX for air lines. However I’d use crimp connections just to be safe. Perhaps you could either rent or borrow a tool.


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killswitch505

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#11
My whole shop has been re-plumbed with pex and all shark bite fittings. It runs 175 psi line pressure and I have had zero problems for the last 10 years.
Same
 

FanMan

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#12
PEX is fine and so are shark bites, but shark bites are expensive. When I plumbed my shop for air I used high pressure (rated 150 psi) polyethylene tubing and plastic compression fittings (220 psi) from McMaster. The tubing is about 1/3 the cost of PEX and the fittings are a lot cheaper than shark bites. 5 years later it's still holding up fine.
 

RJSakowski

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#13
One concern in using plastic for compressed air is what happens if the system ruptures. Unlike water under pressure, compressed gas expands as it depressurizes. Loose lines can whip around with possible serious consequences.
 

keebie1984

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#14
One concern in using plastic for compressed air is what happens if the system ruptures. Unlike water under pressure, compressed gas expands as it depressurizes. Loose lines can whip around with possible serious consequences.
That’s why you strap/clip the supply line down every so often, every couple feet would be or should be sufficient in most applications.

That’s also why I’d prefer using a metal compression type fitting over a plastic sleeved one....even in the gulf on boat landing pull stations we install nylon ferrules in the compression fittings and one can pull the poly flow line out of the fitting when jerked hard to esd the facility.....matter fact BSEE the gov regulator and inspectors look for that they don’t have metal ferrules because it just won’t pull through....

Plastic will compress then up n greater forces slide against plastic but will be bitten into by a metal ferrule until enough if possible force applied to actually stretch the tubing

I’m a Sr. Pneumatic Instrumentation And slow speed motor controls specialist in oil and gas facilities in the g.o.m.


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PHPaul

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#15




After considering pressures and volumes required and pricing everything out, I decided to go with 3/8 polyethylene tubing and plastic PEX fittings.

100 feet of tubing, all the fittings, clamps to tack the tubing to the beams, and two water separators - enough to do two drops in the basement, one by the machines, one in the hobby room for the airbrush - came to just under $100.

I did decide to add an additional regulator to the drop in the hobby room as I may need to adjust pressures for the airbrush and it'll save running up to the mudroom every time. Need to get some pieces-parts for that.
 

derf

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#16
You'll soon find out that 3/8" tubing is not big enough for any volume, and the plastic fittings are the weak link.
 

FanMan

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#17
I agree that 3/8 is on the small side. My (1/2 ID) plastic tubing and fittings have held up for 5 years of frequent pressurization and depressurization (I don't leave the compressor on all the time).

My plastic line never gets touched, though, it's up in the rafters and connects to 6" steel nipples everywhere there's a quick disconnect for tool hoses.
 

PHPaul

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#18
You'll soon find out that 3/8" tubing is not big enough for any volume, and the plastic fittings are the weak link.
For general use, I'd certainly agree with you. However, this line will only run a mister nozzle and perhaps an airbrush, so volume really isn't an issue. Also I plan to regulate the line to 50 psi max and more likely run it at 25 psi.
 
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