Copper Air Lines?

[frank_f15]

standard plumbing solder i.e 95/5, silva-brite, bridgit, etc. will take well over a 100 psi. BUT psi is not the only factor, vibration, shock and temp could all play a majior factor. as franz said we use lots of copper in ac&r , running pressures in the 300# pound area and more when a condenser is not up to specs.but the defining factor is the joint medium used and the expertise of the guy doing the soldering.even a water line at min. pressure can make quite a mess when it lets go, so a n air line or refer. line letting go in your face is really not fun.

 

[Anonymous Poster]

A 100" line of 1/2" copper probably won't bother you blowing up a tire, or even painting with a spray gun, but it's gonna murder your performence with a decent 1/2" impact gun.
The cost consideration between 1/2 and 3/4 copper ain't enough to not use the larger line. If you must use 1/2" for 100 feet, stick a small tank on the end of the line to compensate for air line resistance.
My shop is plumbed with 3'4 black iron, with a second air tank at the far end of the line. I can run a 1" tire gun any place along the line with no loss of performance.
I also have a couple 3/8 copper drop lines running to regulators for painting, soldered with 50/50 solder, and have not had a problem with them. They were installed to insure water could not accumulate in the lines.
I also have 2 water seperators between the compressor and the air system. When I paint something I run a water cooled water seperator ahead of the regulator and gun line.
I akso have a 3/4" black Poly line that runs to the house from the shop system, underground. I keep that line regulated down to 90#, and have never had a problem with it.
Drainage of water trapped in the compressed air is the biggest thing to be considered when Installing a system. If you don't drain an air system you will replace it.

 

[Boner]

Thanks for the good info, Franz. Will come in handy when I plumb air in my shop.
I was going to use SCH40 PVC since it's good to 450psi, and my compressor shuts off @ 140, but I am now thinking about copper. The only problem would be soldering the joints. (I ran into this plumbing my bathroom & heat pump water) The heat from the torch was melting my insulation. This would only be worse with silver solder since more heat would be needed. I suppose I could make some sheilds...

-Ben

 

[Anonymous Poster]

Only problem I see is way too much unused floor, but don't worry, I can fill it up for you real fast.
The amount of heat required for refridgeration silver solder isn't much more than is required for 50/50 solder. The big tricks are cleaning and the flux. 1/2" drywall with a piece of flashing in front of it will work great for a heat shield, and with a bit of planning you can minimize the joynts you actually have to solder in place. Actually, at 140# of air, 50/50 solder would be more than sufficient for compressed air.
The nice part about a soft solder joynt is that it will seperate itself when water freezes in the line, and mimize the damage.

 

[looch]

Nice freakin' shop! Only one problem - getting enough toys to fill it /w3tcompact/icons/wink.gif!

I am jealous.

By the way, thanks to everyone for the great advice.