Copper for compressed air lines??

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By looking at the set up there's some corrosive being sucked into the air lines , like bleach or ammonia , or stored fertilizer . Chemical fumes do lots of this type damage. The shop next to mine we installed copper forty years ago and have never had a problem , the tank for years only got emptied about once a year. Mechanics don't do much painting so a little moisture didn't bother . Plus it was a three hundred gallon tank.