Replacing the compressor drain

So my drain was clogged on my compressor. Fully open, nothing was coming out at all.

I pulled the drain itself out, turned it on for a few minutes and let it blow all the E36 M3 out.

Now what it's like to do is use black pipe to bring the drain out from under the compressor with a ball valve to drain. 

What should I use as sealant on the threads?

Looked like I broke red locktite getting the drain out, should I use that or something better?

I don’t have an answer, but am interested in the responses - my compressor has the opposite problem, I can’t get the drain to close completely so I lose a bit of air pressure constantly.

I did exactly what you're talking about, for the same reason. I used regular ptfe thread sealant and haven't had a problem. I specifically used Rectorseal Tplus2 but any thread sealant will work.

I put a nipple and 90-elbow on the bottom of the tank, then a short pipe out from the elbow, then a ball valve on the end. I later adapted the ball valve to some small tubing and ran the small tubing outside to stop blowing rusty water all over my work space.

In reply to dculberson :

Ok, I just wanted to double check. I've got some megalok, red loktite, and a few other thread sealants lying around, just didn't know if there was something special I should use for air.

Yeah... not the red loctite.  Teflon tape, pipe sealant, etc.

You don't actually have to drain them. Eventually, the tank will drain itself!

In reply to RevRico :

Sorry if I wasn't clear - thread sealant is different from thread locker. Red lock tite is to keep a fastener from rotating, thread sealant is to keep things from leaking past the threads. You shouldn't use red lock-tite on the threads, as you do want this to be servicable down the road.

dculberson said:

I put a nipple and 90-elbow on the bottom of the tank, then a short pipe out from the elbow, then a ball valve on the end. I later adapted the ball valve to some small tubing and ran the small tubing outside to stop blowing rusty water all over my work space.

This, sir, is a good idea.  I will be copying you this weekend!

In reply to dculberson :

No, I just don't think I was clear in what I was saying. 

I'm gonna use this stuff

 it specifically says black iron and compressed air on the side. It's cold so my hands were shaking too much for a picture of the fine print, but it's there. 

Says right on the label:  For use only with natural gas and LP gas.  Is that what you run in your compressor?

I put a ball valve and a 220v 1/8" NPT NC solenoid valve on mine, with some 1/4" poly tubing on the output side.  I wired the solenoid in parallel with the motor and just leave the ball valve cracked a bit so that every time the motor runs it blows down a bit.

In reply to Dr. Hess :

I think you're mis-reading that label. It says it can be used for natural gas and LP gas in vapor state only. It's good for other substances in gas or even liquid form, given the "12,000 psi hydraulic" resistance. It also lists compressed air specifically in the applications part of the label.

@RevRico: I think that would work fine!

I bought an eBay air-compressor-automatic-tank-blower-off-inator. It's awesome. Scares the neighbours when it blows off every 20 minutes, though.

dculberson said:

I did exactly what you're talking about, for the same reason. I used regular ptfe thread sealant and haven't had a problem. I specifically used Rectorseal Tplus2 but any thread sealant will work.

I put a nipple and 90-elbow on the bottom of the tank, then a short pipe out from the elbow, then a ball valve on the end. I later adapted the ball valve to some small tubing and ran the small tubing outside to stop blowing rusty water all over my work space.

Did exactly the same thing, well not the extra tubing thing as my compressor is close enough to the overhead door that I can direct the spray outside.

SkinnyG said:

I bought an eBay air-compressor-automatic-tank-blower-off-inator. It's awesome. Scares the neighbours when it blows off every 20 minutes, though.

Put a muffler on it.

Finally got to Rural King and got the drain put together. It's already installed. Sounds like it leaks a tiny bit, but it works. Blows out like a cannon too. I might have to do something with that down the line.