News:

Check out the newsletters posted at our main club site:  http://57fordsforever.com

Main Menu

Using pic water pipe for airlines?

Started by Zapato, 2016-11-16 23:32

Previous topic - Next topic

Zapato

Anyone use plastic water lines for air lines.

Zap -  :unitedstates:
Zapato

Cruise low and slow.......Nam class of '72

lalessi1

DON'T. A common misconception is that 150 psi is the same for water and air. Air is a compressible fluid, water is not. The amount of energy that can be stored in compressed air is huge, the amount of energy in compressed water is neglible. A failure in a PVC plastic air line can cause an small explosion. The strength of PVC exposed to light and temperature cycles will change with time. It may work and I have seen it used but it is aimply not safe. PVC is not even rated for compressed air use.
Lynn

gasman826

I live on the edge.  I've had two shops with the air plumbed all with PVC.  There are different pressure ratings on the PVC label some as much as 600 psi.  I used larger diameter PVC to increase the volume, ease installation, and aid in cooling.  A pound of pressure is a pound of pressure.  Air compresses more than liquids so a failure under pressurized air will be more explosive.  We've all seen a tire failure or an air hose burst.  The danger of using PVC is not so much the failure of the PVC from age or wear-and-tear.  The danger of failure is from the outside.  An example would be if something fell over or into the PVC and crushing it.  As the air escapes, it could carry pieces of PVC (shrapnel) with it.  To avoid outside damage, some recommend using steel piping in the danger zone.  I ran 2" PVC around the ceiling and smaller diameter drops.  All PVC terminates five feet above the floor.  All water traps and quick couplers are above the typical area where something would fall or somehow damage the air lines.  PVC has huge advantages like ease of installation, no special tools, light weight, cleaner (no rust or oil), cools better (less moisture in the lines), readily available and cheap.

I even built a custom, PVC air tank for the air ride system in the '57.  It is shaped to tuck up under the rear bumper.  Same advantages like light, no rust...just don't run into my rear bumper, it might explode.

Ford Blue blood

Certfied Ford nut, Bill
2016 F150 XLT Sport
2016 Focus (wife's car)
2008 Shelby GT500
57 Ranchero
36 Chevy 351C/FMX/8"/M II

Zapato

Gasman can you elaborate on your water traps. Homebuilt? Pictures would be great.

Zap -  :unitedstates:
Zapato

Cruise low and slow.......Nam class of '72

gasman826

Where ever there is a low spot in the plumbing, I install a 'T' pointing down, add a little pipe and terminate with a valve.  All the drop down pipes have a T with the air fittings (coupler) pointing off to the side.  The down side of the T continues to a valve.  From time to time, I go around the shop and crack the valve.  I also use down pipes after the valve so I don't get wet.  The PVC is really good about not condensing moisture.  Most of my systems moisture will be in the tank which I bleed 2-3 times a year.  I don't use a water separator to paint.  I only use a disposable filter at the gun.  I don't paint enough to have a whole system separator.

lalessi1

Guys, I stand by my earlier post, I have designed hi-pressure compressed fluid distribution systems in the past as part of my career. PVC is not a good material for this application. There are plastics that can safely be used for compressed air, PVC is not one!

Moisture is an issue in an air system the "tee trap" is a must as a first pass, a mechanical separator is a the next thing that should be used prior to a filter separator.
Lynn

RICH MUISE

Years ago in a California machine shop I was managing, we had pvc pipe for an extension into a back room. I remember well driving the kid to the hospital that had a pointy piece of pvc shrapnel imbedded in his cheek just an inch below his eye when he hit the pipe with something and it exploded. Not worth the few $ in savings.
I can do this, I can do this, I, well, maybe

gasman826

Of the many shops I worked in, all air lines were plumbed with schedule 40 black pipe.  Schedule 40 black pipe was rated at 220 psi.  Typical operating pressure ran at 175-185 psi.  After years of corrosion, those pipes got to be scary too.  I think hitting anything under pressure is a bad idea.  If I was plumbing air in a shop that the public frequented, had employees, had visits for my insurance company, a timely OSHA inspection, I think I'd use the plastic air line material that is used in heavy equipment.  That semi rolling up on your back bump has brakes feed with plastic air lines.

Ford Blue blood

For home shop use hot water PVC should last a life time.  The prospect of hitting it (if correctly installed) is very low.  My current shop has schedule 40 because I had it.  All the previous places I have set up used PVC.  Never had an issue.

All my down pipes are off a T.  The bottom of the T has a three foot 1/2" pipe into a 4" cap with a 6" section of 4" capped again with a 4" cap with a ball valve to drain.  The horizontal runs drop 1"/12' away from the compressor with a 90* down to another trap.

My shop air and paint air are two separate systems.  The paint air runs up from a T with a trap to a small separator.  The paint air and air lines are used for only paint, not even inflating tires, just painting.  Keeps the moisture and contamination to a minimum so the filter on the gun has almost nothing to do.

I bleed my system once a week.  Here in AL we make a butt load of water with the compressor!
Certfied Ford nut, Bill
2016 F150 XLT Sport
2016 Focus (wife's car)
2008 Shelby GT500
57 Ranchero
36 Chevy 351C/FMX/8"/M II


Frankenstein57

My compressor is plumbed with black steel pipe, mostly due to short distances and I'm a plumber. My buddies shop is all pvc, and he uses his shop a lot, with no issues.   Mark

Mark

I'm a plumber and would never use PVC for air lines, or want to be any where near one some "farmer" put together. A cinder block will hold your car up too, but I wouldn't get under it. A pressure test for inspection on waste and vent is done at 5 psi and I have seen what it can do. PVC is NOT made to do air lines.

57chero

Lot of plumbers on here, I'm a plumber also and did mine with 1/2" copper.

suede57ford

If you plumb with steel pipe it allows the air to cool some before traveling to the water trap.  Air has to cool for the moisture to drop out.   In order for a water trap to work properly it needs have air run through a length of metal pipe with some ball valve dumps below the air fittings or water trap.

A water trap mounted on/by the compressor will not work efficiently, as the air does not get a chance to cool down.

You notice you get water drops from an air hose, tool, or paint gun, because when the air goes through a "Nozzle" which is your paint gun, air blower, or tool, then the pressure drops and then the moisture falls out of it.   

It's thermodynamics.  the air will hold moisture when hot and under pressure and drop the moisture when either the temp air temp drops or the pressure drops(nozzle or tool).

Long runs of steel pipe up and down with drops will give you the driest air.  Plastic or PVC insulates the air so you don't get a cooling of the air before it flows over a drop, beside the danger factor with plastic.
57 2dr Sedan, Black,VR57 Supercharged Y-block
57 T-bird, 460 C6
57 Ranchwagon, 5.0 AOD
57 Ranchero, VR57 Supercharged
57 Courier Delivery, 460 C6
57 2dr Sedan, Red/White
69 Mach1 428 R-Code
69 Talladega 428
69 Bronco 5.0
70 Torino Cobra SCJ 4spd,4:30 Drag Pak
34 Ford P.U. 427 Ford, 2-4s
69 Boss 429