Darn it...!!! A leak in my compressed air sytem...

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8-Ball

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Bas

Recovering tool addict
Bas
Corporate Member
Sorry to hear about your problems, air leaks can be a pain. I don't think you can improve much on using Dawn or other dishwashing liquid. Just make sure you also grab a can of patience. BTW, how do you like the RapidAir system? I've been looking at both that one and the HF kit.
 

Charles Lent

Charley
Corporate Member
Before you decide that you have a compressor leak, unplug the air line from it and see if that reduces the compressor cycling. If it does, your most significant leak is in the hose and connections. A few drops of dish detergent (any brand) in about 6 oz of water is all you will need. Using a small brush, like a glue or acid brush, just paint the water/detergent mixture on all of the pipe connections slowly while watching for bubbles. If it's a significant leak, the bristles of the brush will foam up as you cross over the leak. A smaller leak will just blow a series of very small bubbles behind the brush. Patience is key here. If you find and fix all of the leaks your compressor should only run when you use some of the air. I leave my 18 cfm shop system with about 10 quick connect couplings and several lines powered ON most of the time, because it only runs when I use air from it.

Charley
 

Bill Clemmons

Bill
Corporate Member
Before you go to the bubble method, you might try turning everything off in your shop and then go to each fitting and just listen. Sometimes you can hear a very slight "hiss" and pinpoint a leak. Doesn't work every time, but maybe worth a try.

Also, I've switched to the pink teflon tape for all my air fittings. I was using the white (I think) tape, which is good for water fittings, but the pink seems to be better for high pressure air fittings.

HTH

Bill
 

bholcombe

New User
Ben
Just put your soap solution into a spray bottle and spray it on, shouldn't take much to find the source(s) that way.
 

Skymaster

Jack
Senior User
Teflon tape is pretty in pink :gar-Bi Seriously tho it is a heavier duty tape primarily for water piping.
White is just general purpose,pink water and yellow for gas piping :gar-Bi:gar-Bi
 

jerrye

Jerry
Corporate Member
"Always leave the first 1 to 1 1/2 threads without Teflon tape to keep it out of your system. If you tape all the way to the end of the fitting you can get tape in your system-something you DO NOT want."

From a former hydraulic & pneumatic engineer that I worked for...
 

Alan in Little Washington

Alan Schaffter
Corporate Member
Quick disconnects are notorious leakers and I don't know if there is anything you can do, except replace them and even that may not work 100%.

I have plenty of places for leaks- two regulators with oil/water separators, a hose reel and four quick disconnects in the shop, a regulator with oil/water separator, hose reel and one disconnect in the garage, and 12 pneumatically operated blast gates each with a pneumatic solenoid valve and actuating cylinder and tons of fittings. I have shut-off valves to isolate parts of my system but often forget to close them so my compressor cycles every few hours.

Since my compressor is at garage level, and not in the shop, it is inconvenient to close the tank valve so as soon as I find a 1/2" i.d. solenoid valve rated at 175 or higher, at the right price, I plan to install a master shut-off valve on my tank and have it triggered by the shop light circuit.
 

FredP

Fred
Corporate Member
I get leaks sometimes too but the best solution I have found is to turn the compressor off when I am not going to be in the shop for more than a hour. I cooked a real nice compressor a few years ago when one of my airlines burst in the middle of the night. My shop is detached from the house so I didn't hear it running. Most compressor motors are continuous duty but the pumps are not!:gar-Cr It was a hard lesson but one well learned. good pumps are not cheap. I always cut the breakers off for the compressor and the heater before leaving the shop.:wink_smil
 

TracyP

Administrator , Forum Moderator
Tracy
Don't Dilute The Dawn:no::nah::no::nah:. The More dawn viscosity, the better the leak detection!!
 

Woodman2k

Greg Bender
Corporate Member
Mike,
when we are testing the production compressors in work for leaks we use an amplified microphone and headphones and can hear air leaks 50 feet away.It looks like a microphone in an inverted funnel and it's very directional.If you use a soapy solution use a higher concentration of soap to water so it's clingy and it will bubble over the small leaks as well.Spray bottle is better than using a brush,the brush will have a tendency to make the soap foam as you apply it.Loctite just came out with a new thread sealant for fittings under 2 inch and it is the best we have used.It looks like a yellowish lacquer.I think it is the 545 Thread sealant.We build units that go up to 240 psi and we can't afford any leaks on the production line .Let me know if I can get you any more info.
Greg

PS always test for leaks at your max pressure.
 

ehpoole

Administrator
Ethan
For detecting leaks I usually use a ready-made solution sold for detecting leaks in HVAC and Gas lines -- mostly because it's just very convenient to have on hand and comes with an applicator swab built into the cap. When you apply it liberally to each joint (and if you have Tees, Elbows, couplings, etc., cover the *entire* fitting because sometimes they have casting or extrusion defects) you can expect to see either significant bubbles if it is a fast leak, or a slowly forming froth if it is a very slow leak. If it is an extremely slow forming froth, don't bother with the joint unless you are an utter perfectionist, such leaks can take weeks to months to leak just a few PSI off even a very small compressor tank (and will never be noticed with larger tanks). Don't forget that your quick disconnect fittings can also be a major source of leakage, especially as they become worn.

I usually use white teflon tape for my air fittings, but I will wrap the fitting 6 to 8 times to ensure a good seal with air lines. Air leaks so much more easily than water, so you need to use enough tape to ensure that there are no unfilled gaps. As mentioned in an earlier posting, you should be careful to keep tape and pipe dope away from the very first thread. The act of threading the joint together tends to shred the tape and you want to ensure that the tape is trapped between the threads and not lose in the pipe (even so it is a good idea to purge each leg under pressure for a few seconds after assembly and initial system charge.

If I disassemble a previously taped joint, I use a pick (similar to a dentist's pick) to clean off all the old tape from each fitting (both male and female halves) -- especially any bits that might come loose in the line when reassembled. You can also use a rag and pick to remove excess pipe dope from fittings as well.
 

petebucy4638

New User
Pete
Finished installing a RapidAir compressed air delivery system, cranked on the compressor, and it leaks. Takes about an hour and a half for the compressor to cycle. At that rate, it should be rather easy to find, but thought I'd post it up here before I start looking for the leak in earnest to make sure that I didn't miss some trick in installing the fittings or if someone has some surefire bubble concoction... I was thinking either using some Dawn diluted down or stop by the dollar store and pick up some blowing bubbles... I used Teflon impregnated pipe dope on all the manifold fittings instead of tape. I do have a mismatch of quick disconnects that I've picked up over the years... might be time to marry them all up (same manufacturer)... I HATE FINDING LEAKS...!!!

ggggrrrrrrrrr

I was taught by my father to use Palmolive dish washing detergent mixed with water. From the old days he said that it was totally non-corrosive. My guess is that there is not much of a difference. Garden variety teflon pipe dope is not always the best choice for high pressure air. I prefer the yellow gas tape. It is thicker and seals better, in my humble estimation. We test gas pipe at 120+PSI. I can't remember the last time that I had a leak using the yellow teflon tape.

Pete
 

Glennbear

Moderator
Glenn
I get leaks sometimes too but the best solution I have found is to turn the compressor off when I am not going to be in the shop for more than a hour. I cooked a real nice compressor a few years ago when one of my airlines burst in the middle of the night. My shop is detached from the house so I didn't hear it running. Most compressor motors are continuous duty but the pumps are not!:gar-Cr It was a hard lesson but one well learned. good pumps are not cheap. I always cut the breakers off for the compressor and the heater before leaving the shop.:wink_smil

#1 The other advantage to tripping the breaker when not in the shop is that it isolates the compressor motor from power line surges (lightening). I also close off the main line so that any leaks in the piping do not drain down the tank. :wsmile:
 
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