Copper for compressed air lines??

mhagadorn

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Ugh, I thought I was being wise by installing a bunch of copper air lines last year. I had PVC for about 20 years, pressurized 27/7/365, never had a problem. Now, I have a bunch of corrosion in the copper I installed. Is this normal?

Corrosion has developed in my new air filter / regulator as well. I'll try to get some pics in a followup post.
 
b8b9a93ea30b78e85487363f0975058a.jpg

This was after I cleaned the regulator as best I could without abrasives.

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I built a large copper air system that was in use for about 20 years, it didn't have any corrosion issues, so I don't think its inherent to the material. I wonder if you are having some sort of electrolytic or galvanic problem, especially in such a short time.
Yes pictures would be helpful.
 
Crossed posts,
That looks more like it was caused by the soldering flux. Excess flux will cause some surface oxidation if left on or in the pipe, in normal water supply service it is washed away when the pipes are filled and is (should be) wiped off the outside of the joints after sweating. It doesn't get washed away in an air system. Personally, I wouldn't worry about it, it probably won't progress much further. If you get corrosion at the threaded connections between the copper and the filter regulators, that would be a problem.
 
The pipe picture I posted above is after my drip loops, before the filter / regulator. I only took that apart to investigate because my filter / regulator was corroding and filling up with garbage. The copper after the filter regulator is also all flaky green inside.

Maybe electrolytic, or I am now wondering if flux from soldering the copper could do to this. I had some old school flux that I loved, but I ran out of it and threw away the container. Maybe it was acid. Not sure if I should try to clean the copper, or ditch it. I really want to know what is going on. I hate issues like this.

Other than my compressor tank, there is no steel in my system. When I bought the compressor, I fogged the inside of the tank with zinc primer and then Krown oil. After a year of heavy use, the inside of the tank looks like new (painted and oiled).

My system plumbing:
1. 60 gallon porter cable compressor
2. 304 stainless pipe elbow & nipples
3. 1/2" brass ball valve and brass hose swivel union
4. Air hose between the tank and the copper
5. Brass hose barb threaded into 3/4 copper
6. about 20 feet of 3/4 copper (2 drip loops with brass ball valves at the bottom of each loop)
7. 3/4 copper goes in and out of the aluminum regulator / filter
8. a few feet of 3/4 copper out of the regulator / filter (tees and ball valves)
9. 3/4" rapid air which goes to my machine shop and two garages.
 
LOL. Another cross post. Thanks. Yep, maybe flux. All my copper to remove water really didn't do much for me. I have now built a refrigerated dehumidification system. I may ditch most of the copper and thoroughly clean what I keep. I did (always do) clean flux off the outside. Maybe the inside will be better if I clean it too. I can't imagine many folks clean the inside of their copper air lines.
 
I spend a good deal of time and money, piping my compressed air system, in copper. About 6 months after I put it in, I had to take it out, my local residential plumbing code, does not allow the use of copper for compressed air. We were in the process of new meter water supply lines from the street and new water meters, which had to be inspected, the violation was noted then. They gave me 10 days to remove it, or fines, but the killer was they informed the insurance company, they gave me 30 days to remove it, or total loss of homeowner’s insurance coverage. So out it came, in went black iron.
 
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Probably true, but many people don't solder...they opt for compression or flare connections.
 
I spend a good deal of time and money, piping my compressed air system, in copper. About 6 months after I put it in, I had to take it out, my local residential plumbing code, does not allow the use of copper for compressed air. We were in the process of meter water supply lines from the street and new water meters, which had to be inspected, the violation was noted then. They gave me 10 days to remove it, or fines, but
the killer was they informed the insurance company, they gave me 30 days to remove it, or total loss of homeowner’s insurance coverage. So out it came, in went black iron.

Dang, that's unfortunate.
 
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