Kitchen tap tail size
- Thread starter DiyNutJob
- Start date
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Just to be fair - there's actually nothing wrong with compression, it has it's place, especially where pipework may need to be demounted to get access to things and then remade again.
I find the trick with compression is -
Reusing old fitting and olives - 2 wraps of gas PTFE tape around the olive , no where else - don't overtighten
Reusing old fittings with new olives - copper olive nothing, brass olive then a wrap of gas tape around the olive, nowhere else - don't overtighten
New compression fittings - doesn't need anything, just made tight enough to grab the olive - don't overtighten
If a compression fitting leaks for whatever reason - anywhere - back the nut off half a turn and re-tighten back up plus a 1/4 turn, if it doesn't stop weeping then remake the connection. Don't be tempted to keep tightening, it will only misshape the olive and neck the pipe.
Oh dear - redo them and get the PTFE tape off of the threads of the fittings - that's not where it supposed to be, the water tight seal isn't made at the threads - tape only goes around the olives and no where else as that's where the seal is made.
Yes I understand. There's no room to do anything except full disassembly. Sealing the threads will have to do.
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Fair enough and I do understand the thinking but honestly, it doesn't do anything. Compression fittings don't create the water seal at the threads, they create it at either end of the olive. Loosening and tightening the nut will have been what's eventually sat the olive down and sealed it up.
That being said if everything is dry now then let's not upset things.
Is vaseline an acceptable substitute as a temporary plumbing grease? I can see some of these problems are caused by wonky olives. The olives not freely sliding on the pipe during compression would cause that.
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The olives, once compressed, wont ever slide on the pipework. They are compressed between the fluted edge of the body of the coupler and the fluted edge on the inside top of the nut as you tighten it, being compressed and shaped between the 2 and the surface of the pipe. That's why the olive is the shape it is. It's those fluted edges and the ends of the olives that mesh and compress together onto the pipe that forms the water tight seal.
The trouble is they then take a certain shape and when disconnecting and then remaking the fitting they don't always go back in exactly the same place, hence the need to use a wrap or 2 of gas PTFE tape ( or 6 or 7 of water PTFE) around the old olive. The tape fills up those little inconsistencies and provides a surface to seal against and makes the join watertight again.
Lack of lubrication between new olive and pipe causes one side of the olive to bind with the pipe producing wonkiness. This makes the joint leaky prone. Greasing during the initial compression would prevent the binding and produce a square compression on the olive.
Nope - Misalignment of the fitting onto the pipe or pipe into the fitting prior to tightening will do that, there is enough play in a new fitting/olive to allow it to be slightly misaligned. But even then that doesn't really matter. The olives shape allows for the pipe and fitting to be a mm or 2 out and it'll still seal up ok.
I must have fitted hundreds of compression fittings over the time I've been doing this and have never ever used a lubricant, It's just not something that's ever needed.
I must have fitted hundreds of compression fittings over the time I've been doing this and have never ever used a lubricant, It's just not something that's ever needed.
OK. But I would use it. It would remove that horror movie door squeal noise that indicates olive binding.
The problems I faced on this occasion was a double whammy: wonky olives and and brass olives that constricted the pipe causing deformation. Both promotes leaking. But all that is water under the bridge now.
That's not the olive binding lol, that's the tightening squeak, that's when you know you've tightened the compression nut enough and all the surfaces are nicely mated. That's a tried and tested old school indicator that the compression fitting has been tightened properly and when to stop, it's certainly more noticeable when using brass olives than copper.
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