Sealing around a compression joint

[AdamW]

OK, so I now have all of my compression joints leak-free and working fine. However, as some of them will be in innaccessible places or places where leaks will not be noticed after I have finished the bathroom, I am hoping to somehow ensure their seal for the future.

Is there some kind of putty, clay or resin on the market that I could "encase" the fitting with? I know this would make removing the fitting impossible without cutting out the section of pipe, but I really want to make sure the bu**ers are watertight.

I am aware of plumber's mait and it's wonderful "never set" characteristics. This flexibility would be required seeing as something entirely solid might crack under pipe expansion/contraction cycling. However would plumber's mait do the job? It really does need to be watertight, and not allow drips past ever.

 

[AlanE]

I would have expected this question to have been asked last Thursday.

Plumbers mait would be 'washed away' by any leak.

Alan

 

[sterose]

Firstly, Plumber's mait will not be "washed away", it will just prove ineffective because it is not designed to be used against pressured.

Secondly, if the joints aren't leaking now, they never will. NEVER.
I had the same worries when I first started, but the worst you get from compression is a little drip, which, to ease your mind, gets less over a period of time. That is, small leaks seal themselves after a while due to minerals in the water.

If they are leaking now, tighen them up just a little bit, and it should stop.

 

[AdamW]

Is plumber's mait more for sealing around sink wastes and the like then?

 

[soubriquet]

plumbers mait is for bedding joins in cast iron soil pipe, for sitting sinks on pedestals etc.
There are many sealing products which are designed for threaded and compression joints. Some, such as Boss White, are fine for central heating but not suitable for potable water. If water is the thing to seal, Jet Blue, available at plumb center is a good one. There are various ptfe seals, in the form of pastes and tape. All of these are designed to be used in the joint, they fill any spaces between the threads or between the olive and the pipe or fitting. If you are using nice clean pipe and fittings you should get a perfect joint metal to metal, no pastes needed. On scratched, previously painted, or otherwise nasty pipe, theres no shame in using a joint paste. A very light smear is enough. Trying to encase joints externally is futile. if it leaks through a compression fitting it will not be stopped by a blob of filler. Check all your joints, wipe them dry with a bit of toilet paper, and fill the pipework to working pressur. If another touch with toilet paper comes away damp, then drain down and remake the joint. Overtightening causes more leaks than undertightening. Practice makes perfect.

 

[AlanE]

Sterose said "Firstly, Plumber's mait will not be "washed away", it will just prove ineffective because it is not designed to be used against pressured."

I used inverted commers around washed away because the comment aptly described the result not perhaps the literal action!

You agree that plumbers mait if stuck to the outside of a join that leaked would become unstuck from the pipe and the water would continue to leak. If this leak became of any consequence then I think you must agree the plumbers mait would become a sticky mess before becomming such that it fell away.

Try mixing said plumbers mait in hand and see the result!! This product is intended to be used for bedding in etc where the joint is effectivly in compression.

Alan

 

[AdamW]

You see, whilst the joints appear fine now, I fear I may have overtightened them. When I first did them up a bit more than finger tight they dripped. So I did them up a bit more, it got less. And by the time I had stopped the drip I was having to put quite a bit of force into a pair of 9" adjustable wrenches (one on the joint, one on the nut).

When doing up the last few I did try the 1 and a quarter turn rule. On some of them it was hard work to put this much torque in. On others they still seemed a bit too easy to turn to stop there. This was the case both with screwfix compression fittings and Wickes fittings.

Is this right?

 

[AdamW]

However (separate post because this is a second part of the same problem!) I am still having a problem with the sink and bath traps.

I bedded the wastes into the sink and bath with the supplied washers, with a big smear of silicone underneath first to fill in any gaps. Then did them up firmly and wiped away the excess that squeezed out. Now, THOSE don't leak. I have tried keeping a sink and a bath full of water with the plugs in and there is no problem.

However, the joint between the trap and the waste seems to leak in both cases.. I found this unusual seeing as I would think the plastic connector on the trap would self-seal the joint. AND I used PTFE tape too.

Seeing as wastes are not really under pressure, would plumbers mait or similar work in this case? I am loath to remove and redo the sink waste as it is a pedestal and the screws are VERY hard to get at (especially seeing as I used 3" number 12s to make sure the bu**er doesn't go anywhere!). And I can't fit my hand in between the trap and the pedestal to tighten it up anymore. But I could just about smear stuff around it.

 

[AlanE]

Are you refering to join at top of trap to sink waste fitting??

If so PTFE tape is NOT used. There is a rubber washer that provides a watertight join every time.

Alan

 

[billy bob]

plumbers mait is for bedding joins in cast iron soil pipe

I have been plumbing for 23 years and I have never used plumber mait for cast iron, you use molten lead and caulk the joint, Plumbers Mait is used for sealing the waste fitting for basins etc, some plumbers now use mastic, but I find plumbers mait cleaner to use

 

[AdamW]

Bah, I just did a bit of a test (i.e. shoved my hand up behind the sink pedestal) and the leak actually appears to be coming from where the waste goes through the sink. Which would suggest that I haven't got it sealed in properly.

I followed articles I had read on fitting wastes and used mastic (silicon) as well as the supplied washer. Without the silicon the waste didn't seem to sit entirely flush against the bottom of the sink.

I guess now I will have to remove the sink, then remove and rebed the waste. So, would you recommend plumbers mait instead of mastic, or should I just use a washer? Being a pop-up waste it isn't a simple matter to just give it an extra turn.

 

[AdamW]

Are you refering to join at top of trap to sink waste fitting??

If so PTFE tape is NOT used. There is a rubber washer that provides a watertight join every time.

Alan

Yes, I did use PTFE tape for that join. I did think that the washer should provide a seal but I thought PTFE couldn't hurt. As it turns out, that join is leak free. Seems to be my fitting of the waste to the sink that is to blame!

How much does a plumber charge to come and fix a 90% functional bathroom?

 

[erethryn]

Secondly, if the joints aren't leaking now, they never will. NEVER.
I had the same worries when I first started, but the worst you get from compression is a little drip, which, to ease your mind, gets less over a period of time. That is, small leaks seal themselves after a while due to minerals in the water.

If they are leaking now, tighen them up just a little bit, and it should stop.

Hi,

I've just plumbed a shower in using compression fittings, and out of the 9 connections, 4 are leaking very slightly. Can someone please confirm that they will stop leaking after a while (preferrably before my living room becomes a swimming pool ). I've tried loosening them off and retightening them, as I may have overdone it initially, but they're still leaking. Any comments/suggestions appreciated.

Thanks

 

[david and julie]

The best thing to do with compression fittings is leave them in your van!unless you have absolutely no choice. No1 fitting end feed no 2 are yorkshire type, especially for neatness. Invest in a cheap blowlamp and pratice on some scrap bits,once mastered the skill will last a lifetime! Fit and forget and cheap to!

Undoing an overtightened fitting will make matters even worse,try some of the products mentioned above to sort it out.

 

[ollski]

Secondly, if the joints aren't leaking now, they never will. NEVER.
I had the same worries when I first started, but the worst you get from compression is a little drip, which, to ease your mind, gets less over a period of time. That is, small leaks seal themselves after a while due to minerals in the water.

If they are leaking now, tighen them up just a little bit, and it should stop.

Hi,

I've just plumbed a shower in using compression fittings, and out of the 9 connections, 4 are leaking very slightly. Can someone please confirm that they will stop leaking after a while (preferrably before my living room becomes a swimming pool ). I've tried loosening them off and retightening them, as I may have overdone it initially, but they're still leaking. Any comments/suggestions appreciated.

Thanks

If you have overdone them and crimped the pipe then they are b*gg*r*d. A tiny drip in a hard water area will stop eventually as the hole gets clogged up but not advisable to use this as a method of fitting.