NOT happy--redoing my plumbed air system

[Jameel Abraham]

I plumbed my shop for air on Monday and Tuesday this week, and noticed yesterday while working in the shop that the compressor was kicking on every 20 minutes or so.

Turns out several of my joints (using 1/2" pipe) are leaking. Very slightly, but you can hear them if you get close.

So I repaired a couple of them, and just for fun (yeah right) sprayed the rest with soapy water. Leaks EVERYWHERE!!

I used teflon tape to seal the joints, but evidently didnt use enough. When I run gas lines I always use Harvey Seal (the yellow dope) and never had a problem. I figured since air isnt flammable I'd use tape since the yellow stuff is so messy. Big mistake.

So for all of you planning to plumb your shop with iron, make sure you use the goop for sealing, and NOT tape. I guess you can use tape, but it takes WAY MORE to seal black pipe than typical water line fittings.

So, I'm out to the shop to completely dismantle probably 50 or more joints and redo them.

Almost makes Black Friday shopping appealing.

[Carroll Courtney]

We all have left a leak or two i our quest for the perfect shop.I try to learn from my mistakes(I should be a genus by now)but I make to mant to keep up with.I use Rector Seal on pipe threads which you can pick up at anyplace in the plumbing dept.Let it set up for awhile and you should be good to go.

[Al Willits]

Dump the Teflon and go with pipe dope.
Rectorseal with Teflon is one that works well.
Also this isn't copper, you can reef on it fairly well, find at least a pair of 14" pipe wrenches and have at it.

If ya lived near me, ya could borrow mine.

Al

[Chris Rosenberger]

I have never had gooduck with Teflon tape. I started using Teflon pipe joint compound in a can. I coat the threads on the pipe & also put a small amount on the threads on the inside of the fittings. I have not had any leaks .

Do not use this process on gas lines.

[Curt Harms]

AFAIK, teflon tape is more an antiseize measure than a leak sealing measure. I use pipe dope with teflon in it, no problems with leaks. There IS one thing teflon tape works well for. If You use screw top jars for storing finishes, wrap a couple turns of teflon tape around the threads before screwing the top on, it certainly increases the likelihood of being able to get it back off again. Saw this in a publication a while ago.

HTH

Curt

[Jameel Abraham]

Whew! I just finished up re-doing all the joints. About 50 that I had to take apart, dope, and re-connect. Several hours later I'm done. I pressurized the system at about 40psi (I usually keep the regulator at 100), sprayed every joint with soapy water, listened carefully, and no bubbles and no leaks! Yeah!! Now I'm happy. Was going to spend the day building an outfeed table for the TS. Well, at least this job kept me away from Menards. Musta been a zoo there today.

So for anyone plumbing air with iron pipe--DON'T USE TEFLON TAPE!! USE DOPE!!

[Shawn Walker]

There is teflon tape made for gas pipe. It's $5.00 a roll at HD. It's thicker than regular plumbing teflon tape. It works well, your connections won't leak.
Cheers Shawn.

[Mike Marcade]

There is teflon tape made for gas pipe. It's $5.00 a roll at HD. It's thicker than regular plumbing teflon tape. It works well, your connections won't leak.
Cheers Shawn.

No matter what ... dope is better than teflon tape. In my humble opinion of course. :)

[Larry Nall]

Plumbing the shop for air is on my do list for the weekend.
Thanks loads for the heads up.
I would have screwed it up for sure.

[Bob Wingard]

I know it's overkill, but where I used to work, we were taught to use dope on both surfaces and tape in between. The dope acts more as a true sealant, and the tape acts as a lubricant, allowing the joint to be tightened a little more.

Overkill, maybe, but we NEVER had a leak !! !! !!

[Bob Feeser]

Just the food for thought, but using copper pipe soldered, especially the thicker grade of copper pipe is preferable to black pipe with a large thread surface that requires sealing. I had a shop that used PVC without any problems. The thicker grade of copper pipe is available at Home Depot, just look in the pipe rack, and you will see another letter designation, like M or L or something like that. It is a little more money.
I think for natural gas applications, where puncture injuries can have devastating consequences, the extra protection provided by black pipe is neccessary, but for compressed air for a shop it is overkill, with difficulties arising from leak problems at higher pressures. (At least more so than soldered copper tubing, or PVC) Just some food for thought for others who are planning on adding air to their shop.
PS: Glad to see you successfully sealed your black pipe system. I did black pipe for the house when converting to natural gas, it's a new medium to work in.

[David G Baker]

Teflon tape on galvanized or black pipe can cause the fitting to be over tightened and split the fittings. I have had this happen several times in the past with imported fittings. I use tape or paste Teflon on plastic or brass fittings and pipe dope on all other fittings

[Tim Wagner]

We used Copper pipe and sweated the joints. Leak proof.:cool:

[Trevor Hughes]

Sorry to hear about your leak problem. I just put up all my air lines about three weeks ago. I used 1/2 copper pipe and soldered all the joints. It was a little tricky at times (my wife was out in the shop 'again' helping hold up eloborate sections). Anyway, immediately fired up the compressor to 135 psi, works like a charm. No leaks.

[Steve Leverich]

I personally hate pipe dope just for the mess - I've been in industrial instrumentation for right at 30 years, have used nothing BUT teflon tape on all kinds of pipe from pvc to stainless, copper, brass, black iron, galvanized, and NEVER had a leak.

I don't use the thin, crappy cheap tape, usually Chesterton - and I never use less than 3 tight wraps CLOCKWISE so it self-tightens when you screw on the fitting - usually 3 wraps for copper/brass/stainless, and 4 wraps for black iron or galvanized or pvc threaded pipe. Doing pvc that way, I can hand tighten most fittings and not get leaks.

This includes pressures to 160 lbs as well as vacuum that's just a little better than a black hole... Steve

[Al Willits]

Use pipe dope, leave the tape for plumbers, they get paid by the hour.
Been in pipe fitting for over 30 years now and I don't know a pipe fitter that uses tape on pipe.

Probably a reason for that...imho

If ya got more mess than a easy swipe with a rag, your using to much, pretty common though and I suppose to much is better than not enough...:)

btw they do use copper for nat and propane lines, code here anyway says ya can, does state how and where its to be mounted though.

Another tip, brass flare fittings normally don't need anything on them, the flare is what seals the fitting, not the threads, key word here is "flare" fittings,in fact anything on the flare can cause problems.

Most of all, when it comes to pipe or copper, I'd go with whatever your comfortable with.

Al....who likes pipe because you can hang stuff off it....:)

[David G Baker]

I was an apprentice sheet metal/pipe fitter for the Southern Pacific Railroad in the Sacramento CA repair shops for a couple of years, the only thing we used was a gray pipe dope on all fittings except high pressure hydraulic lines and hand honed flanges. I think this was before Teflon tape was available and prior to import pipe fittings.

[Randal Stevenson]

I use teflon tape on the connectors that go on the gun. That is the only place, as several shops (some professional, we would loan each other specialized stuff), I have used, use different connectors.

Use a zero pressure coupler, then when not using the tool, I can release the pressure and have no leaks.