Copper for compressed air lines??

Looks like too much moisture in the lines- better drier needed?
M
 
Are you near a factory or power station or some source or sulfurous emission to the air?
it takes very little polluted air to cause the sulfate/sulfide deposit on copper
 
If there is electrical connection between your stainless steel and your copper, you will get a lot of galvanic corrosion. particularly if there is any trace of moisture in the lines. If possible, separate stainless and copper with a short (1 foot) length of high pressure hose - I use hydralic, but any pvc air hose will work.

Solved my own corrosion problem like that using the above (about 10 years ago).

Good luck!
 
I have copper air lines. And all my connections are hard soldered. I do not have any corrosion problems. Using an acid base flux is great to get the solder to flow but has terrible long term corrosion effects. Even if you try to neutralize the acid flux it could still case corrosion later on. I do not use any kind of acid flux for that reason…Dave.
 
Ive had hard 1/2 copper pipe for more than 25 years never noticed a corrosion problem or any build up of any kind. All my joints were soldered with silver solder, to meet insurance specs, I put a new line in a year ago to my mill for a power draw bar, I opted for PEX piping and shark bite fittings.
so far everything is working fine, and no corrosion. I wouldn't worry about some discoloration as longs as theres no big pieces. I would be a little concerned about an aluminum regulator, change it out to a brass unit much more compatible with moisture and more inert
 
That sounds like an unusually aggressive inspection operation. I worked in a plant that had some copper air lines and we had no problems with it. I always put in black or galvanized steel, though. But, I don't know of any categorical prohibition of copper in compressed air service in the usual plumbing/mechanical codes. PVC is not allowed. Probably CPVC also. PEX? I have no idea. The main thing is proper slope, dirt pockets, drains. For instrument air I would consider copper.
 
Mikelkie said:
Are you near a factory or power station or some source or sulfurous emission to the air?
it takes very little polluted air to cause the sulfate/sulfide deposit on copper
Click to expand...
No factories within 10 miles. Woods and farms.
 
At the old shop, we had run some 300' of copper for the air system, it worked well for many years. Then, when we had to bring the spray room up to code, the inspectors made us remove the copper and put in schedule 80, black "iron" pipe. The explanation was, in a fire the solder joints could separate and the jet of compressed air could intensify combustion. Luckily, they only made us redo the lines to the spray room and we were able to leave the rest of it. That's NYC for ya...
 
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