Thread: Air compressor CFM lost-lenghts of black pipe??.

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I've got a 2 stage with an 80 gal tank, then a 60 gallon tank plumbed to it. The compressor does run more to fill both tanks, but it doesn't run near as often. Had it this way for a couple years now and no problems at all. The rest of the system is 1" pipe plumbed to a dryer/separator then a couple of QD's for the air hoses. My garage is small, so the two 50' air hoses cover the whole place. I'm with Charlie and the rest, I don't use an oiler, just keep a bottle of air tool oil handy. The extra tank serves as a very good water trap and air cooler for the system, too! Very seldom that any moisture even makes it to the dryer.

Originally Posted by Dave Severson

I've got a 2 stage with an 80 gal tank, then a 60 gallon tank plumbed to it. The compressor does run more to fill both tanks, but it doesn't run near as often. Had it this way for a couple years now and no problems at all. The rest of the system is 1" pipe plumbed to a dryer/separator then a couple of QD's for the air hoses. My garage is small, so the two 50' air hoses cover the whole place. I'm with Charlie and the rest, I don't use an oiler, just keep a bottle of air tool oil handy. The extra tank serves as a very good water trap and air cooler for the system, too! Very seldom that any moisture even makes it to the dryer.

What Dave says is very true, but his system works because the compressor capacity is more than his use rate. If a guy tries to use a small compressor by adding tanks for added capacity the compressor is still going to run for extended periods once it starts, unless the air demand goes away. There are lots of ways to put a system together, but there's not much way to make a compressor that's too small work right.
On the pipe material, I considered black pipe and had concerns with rust, but by the time I considered the fittings, weight being hung, threading joints, etc to copper the choice for me was hard copper tubing with solder joints like Charlie & Robot mentioned. It's easy to work with, light to hang, and lasts forever.

I plumbed my shop with 1" galvanized pipe. Off of the compressor I have two 1"inline filters and at each drop I have a 1/2" regulator that is off of a tee with a blowdown valve at each also. You do not want to run black pipe as it will corrode inside. Either galvanized or copper or stainless is your best bet. Do not run your header in 1/2" run it in 3/4" or 1" and then do your drops in 1/2". Don't forget to remove that crappy draincock in the bottom of the tank and pipe it out with a proper valve so it is easy to drain your tank after use. This will definately extend the lfe of your system. This is exactly how we install instrument air systems in plants worlwide so I know it works. Oh and yes your CFM will be affected by that 1/2" pipe to some degree at the user.