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Honored Advisor
handy-dan
Posts: 5,377
Registered: ‎03-07-2010
0

Re: Plumbing for air

Flared tubing is used with the more expensive fittings.  Soldered mine years ago and haven't had a problem.  3 /4 inch and bigger good for use in high volume application such as 3/4  or one inch impact wrenches.  Not likely needed in a woodworking enviroment.

 

Dan

Dan
Youngstown, Oh
Apprentice Contributor
Cheapside Mike
Posts: 11
Registered: ‎11-16-2009
0

Re: Plumbing for air

1/2 inch schedule 40 PVC Used it 10 years ago and it had worked perfect...simple just cut & glue

Veteran Advisor
joebtool
Posts: 1,223
Registered: ‎02-23-2010
0

Re: Plumbing for air

I worked for a large millwork shop in the 70's and everything was 1/2" copper w/ soldered fittings. There was an outlet at almost every machine and assembly bench plus two spray booths and we never had a problem.

 

Joe B.

Joe B.

"Better to wear it out than to let it rust."
Senior Contributor
hatuffej
Posts: 466
Registered: ‎10-23-2009
0

Re: Plumbing for air

Stick

A larger pipe volume facilitates a higher air flow velocity and thus a lower drop in pressure at the delivery end. For a small shop, the difference in cost would be minimal. 

Jeff

Frequent Contributor
wericha
Posts: 70
Registered: ‎08-14-2011
0

Re: Plumbing for air

I would highly recommend AGAINST using PVC.  The chances of it shattering are too high and not worth the risk, IMHO.  The higher the pressure generated by your compressor, the greater chance of failure.  Today's compressors are capable of pressures exceeding 150psi, and that is too high for for even thin walled copper.

 

I bought the rapidair basic kit from Rockler for $79 and really like the system. 

Apprentice Contributor
Cheapside Mike
Posts: 11
Registered: ‎11-16-2009
0

Re: Plumbing for air

1/2" Schedule 40 PVC Has a max PSI of 600psi  http://www.harvel.com/pipepvc-sch40-80-dim.asp

Regulate your system to run at 100psi perfect for most tools.

all fittings and adapters needed ar available at the local hardware store

less condensation and no rust

after 10 years of hard use mine has never leaked or failed in any way

Honored Advisor
stick48668
Posts: 11,837
Registered: ‎01-15-2010
0

Re: Plumbing for air


wericha wrote:

I would highly recommend AGAINST using PVC.  The chances of it shattering are too high and not worth the risk, IMHO.  The higher the pressure generated by your compressor, the greater chance of failure.  Today's compressors are capable of pressures exceeding 150psi, and that is too high for for even thin walled copper.

 

I bought the rapidair basic kit from Rockler for $79 and really like the system. 


2nd the motion...

 

Have repaired these lines for others...

 

It's only a matter of time before the shrapnel produced by a break enters the equation..

and it it will have no conscience...



this would have been the week that I'd have finished chewing thru the restraints...
if only new layers hadn't been added....

Stick....
Contributor
DaveS2
Posts: 12
Registered: ‎11-13-2009
0

Re: Plumbing for air

This webpage http://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-d_796.html has a nice graph of Max. Working -vs- Min. Burst pressures based on ASTM standards for PVC pipe.  A 5X safety factor is used.  Considering that pancake compressors top out at about 150 psig, that would be a 10X safety factor for actual working pressure for 1/2" sch.40 pvc.  These pressures are for  73F.  The page notes that at 140F "the strength is derated to approximately 20% of the strength at 73F the burst pressure."  

 

CPVC (chlorinated PVC) is made by a different process and can handle higher temperature conditions with respect to pressure.  This is why it is sometimes used in domestic water supply lines although it is considered more problematic than copper or polyethylene.  Many plumbing sites reccomend AGAINST using air to pressure test PVC/CPVC water lines to system pressures since, if there is a problem/failure, things get instantly exciting!

 

Rigid copper would be a much better choice since the material has a much higher tensile strength.  Max. working pressures can be found here http://www.copper.org/applications/plumbing/techref/cth/cth_3design_burst.html - pop-up table 3c is for thin wall type M tubing, table 3b for medium wall tubing (MUCH stronger).  Use "drawn" side of table for soldered or flared fittings, "annealed" side for welded or brazed fittings (both weaken tubing at joints).  Flare fittings will allow for more convenient replumbing and reduced fire risk in your wood shop.

 

PEX could also be a reasonable choice if you have access to a crimping tool and crimp gauge. According to here http://www.pexuniverse.com/pex-tubing-technical-specs , temp/pressure ratings are 100psi at 180F  and  160psi at 74F. 

Dave
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There is no such thing as safety - there is only risk management...

 

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