Leaking Isolator + Solder vs. Compression?

[SproutsDad]

Hope you can help with my latest nightmare! Advice please on:-

1) Compression vs. soldered where pipework will be inaccessible
2) Can't stop a new compression joint from weeping.

I am gutting and refitting a downstairs toilet, I have exposed the pipework behind a boxed in soil stack and stud wall where I will put access panels where possible but some of the existing compression 15mm 'T' and elbows will be inaccessible behind plasterboard.

1) I read that compression or unsoldered joints should be visible and accessible, otherwise use soldered joints. I feel it best to replace the existing with soldered copper fittings, as few joins as possible behind stud/ box work. Does that sound right?
So I am busy fitting new pipe + fittings to be soldered.

2) Where all this new pipework joins the existing H&C feeds in an adjoining washing room under the sink, I have cut into the cold feed and fitted a compression isolator valve. I have used a copper olive with PTFE tape wound over it. I hand tightened it, then 1/2 turn with spanner. I noticed a small weep from the top nut, so I tightened it, it was still weeping, so I tightened it more !!!

It is still weeping slightly, I have probably overtightened and it is crushing/ distorting the olive into the pipe, which is probably never going to seal.I fear more tightening will just cause damage. HELP please.........!

Problem :- The valve is quite close to an existing soldered 'T' so to get clean pipe I need to cut away approx 20mm pipe and old olive. That will be close to the T. The small tail from it was bent to shape so I'm not sure how much 'good' 15mm undistorted pipe is there to bed a new fitting into.
I could take the soldered T away and replace it, but I feel I am just stripping everything back and back creating more problems as I go just to try and avoid problems in the future - that may never happen. If it ain't broke . . . . !!

And, there must be a mass of speedfit /pushfit/ compression etc out there buried deep in walls and floors, so am I going OTT?
I like to think not, because you haven't seen the state of some of the existing pipework.

 

[ukrobj]

Ideally soldered only in inaccessible area's, for the prime reason if you have a leak on a compression how will you rectify it?

Regarding the leaking compression, remove it, take a look at the compression itself, if its a cheapy one, then it may not be sealing, will also allow you to take a look at the olive. try and little boss green around the olive, may help.

 

[SproutsDad]

Thanks for the quick reply. Good, I almost knew but needed your confirmation on the soldered joints for inaccessible pipework.

I will check the compression isolator valve thjis evening. It was a Toolstation one for only £1 and they are for certain cloned to a low spec in the Far East at that price.
Q1 For a better one, is there a brand or outlet where I can be sure of getting a quality item? Screwfix and Wickes are better than TS but the big plumbing chains?
Q2 I have seen a forum item where someone said to only use copper olives, throw the brass ones as they are too hard!? Most fittings seem to come with curved brass ones, this was a copper bevelled one incl with the valve.
Q3 Boss Green? - I have Boss White, PTFE and liquid PTFE. Should it be Boss Green?

Thanks, will try this and get back later this evening.

(Sprout is the 3-legged cat)

 

[ukrobj]

Brass is slightly harder material, however it tends to be personal preference. I ditch the brass in favor of copper olives, only need a pinch and they are tight.

Doesn't have to be boss green, any fine paste will suffice but as its potable water, don't use anything not approved. Boss White isn't designed for potable water.

You get what you pay for, it could just be a crappy olive. May be worth removing it and replacing.

 

[JohnD]

Provided the pipe was well thrust into the fitting before tightening, and the olive is not hanging off the end, and not distorted, then you can wrap a few turns of PTFE tape round the olive, so they overlap slightly onto the copper pipe on both sides. It makes an excellent seal on compression fittings.

More elderly plumbers will complain that it's not the way things were done in their day. Ignore them if you want a good, watertight seal.

A good soldered joint is always preferable, but if you have had water in the pipe you will find it very very very difficult to get it dry enough to solder.

Cheap isolation valves sometimes start leaking from their spindle for no apparent reason at a random time after their installation. Pegler valves are two or three times the price but a hundred times better.

 

[ukrobj]

Provided the pipe was well thrust into the fitting before tightening, and the olive is not hanging off the end, and not distorted, then you can wrap a few turns of PTFE tape round the olive, so they overlap slightly onto the copper pipe on both sides. It makes an excellent seal on compression fittings.

More elderly plumbers will complain that it's not the way things were done in their day. Ignore them if you want a good, watertight seal.

Very true, but still makes me smile when the lads come from college and wrap the ptfe around the thread of the compression.

Not a clue.

 

[SproutsDad]

Thanks for all your replies, really helpful....

Leaking Compression isolator valve
I checked it and had no more than a couple of small drops in a whole day. It might seal up on its own but could also get worse in the future. I haven't opened it up yet, will do it tonight as it will mean water off everywhere. I thought I had prepared it well when I put it together with quite a few turns of PTFE over the olive before I closed it up - but was that maybe the problem?

I sense the joint it is quite crushed up in there as I did give it a number of turns with the spanner trying to stop the leak. Last night I bought 'better' branded valves and will replace tonight. I prefer to redo or replace it. I will inspect olive closely before cutting it or pipe off.

Olives - copper
I don't see copper olives so often as brass, must be where I shop, and they are a completely different shape - copper are flat / beveled whereas brass are domed. I am always confused by this - will any 15mm olive work in any 15mm fitting? They also seem to vary slightly in diameter, some slip over the pipe quite loose, others are more snug. Comment please.

Jointing Compound
Thanks for pointing out the potable aspect of Boss White vs Green. Many people must use unknowingly use the Boss White one on H&C pipes. Can't the Green near me but bought Fernox Hawk White, is that ok? I noted a comment on it and others that should avoid getting compound under the olive as it makes it slippery and a poor joint !! !? Doesn't sound easy to achieve even if that is true as the olive moves around and compound will get into the joint. Comment please.

Soldering with Yorkshire fittings.
As a DIYer with a box full of these pre-soldered fittings I will use them. I have seen videos showing the usual wire wool cleaning pipe and fitting, flux the pipe, then heat and back off once molten solder appears. But I have also heard of topping them up' with extra solder at the joint openings to be sure? I tried it but find solder in the fitting melts first possibly runs away, and maybe leaving the joint dry inside, before the additional solder melts?? I know that real plumbers use end feed, not yorkshires.
Any comments please on this and using these generally.

BTW - I stopped putting PTFE on the threads long ago when it was pointed out that the thread just pulls, doesn't seal - I hadn't thought of that !!

Thanks again for all your help, much appreciated.

 

[JohnD]

I have a feeling that the pipe might not have been pushed fully home into the fitting. Too much PTFE might contribute to that. I find you get a more certain seal if you push the pipe and olive in bare, give it a few turns of the nut to seat the olive, then it will not move around when you tape it. Two or three turns is enough unless you are trying to reseal a crushed old olive when you might need more to take up the gap, as a last ditch to avoid having to cut the olive off because it won't pull.

 

[SproutsDad]

JohnD - Thanks, the tip on pinching the olive lightly first before putting on PTFE makes a lot of sense. I will investigate the joint closely this evening and report back.

 

[SproutsDad]

I posted to this thread yesterday 22-Jan on a few items........
Would appreciate a reply when someone can, in particular on the subject of soldering, see below ......

Soldering with pre-soldered (Yorkshire?) fittings. - getting a good joint?
I have 15mm pre-soldered fittings to do a run of pipework located under a sink, going through a stud wall and near to plastic waste pipes. So I may need a solder heat mat? Or if possible solder as much as possible away from the final location and then feed the assembly back into place before connecting up to the compression isolator. It is difficult with a blowtorch in a confined space, near plastic and wood, so thought maybe as much as possible done away from situ if I can feed it back through afterwards?
<< Comment please!

Topping up Yorkshire joints?
Videos on pre-soldered joints show wire wool cleaning of pipe and fitting, then flux the pipe, then heat the joint, back off heat once molten solder appears. But some say to also 'top them up' using extra solder at the joint for added security? I tried but solder in the fitting melts first, possibly even runs away, before the additional solder will melt. Could this leave the joint dry inside?
<< Comment please!

Not melting adjacent joints?
How do I keep an existing joint from loosening / melting when doing a new one near it? I have put a damp rag around it? What is the proper way?
<< Comment please!

I know that real plumbers use end feed, not yorkshires, but us DIYers !!!.

Any comments please on this and soldering generally would be much appreciated.
Thanks

 

[SproutsDad]

Please someone, any chance of a reply to my post of a few days ago, see above, from Wed 23-Jan on :-

1) Soldering with pre-soldered (Yorkshire?) fittings. - getting a good joint?
2) Topping up Yorkshire joints - extra solder?
3) Not melting adjacent joints?

Your valued input would be very much appreciated.
Thanks very much.

 

[sooey]

1) Soldering as many joints as possible before putting them in situ is a good idea.
2) It sounds to me like you're using too much heat, turn the torch down a bit and do the joints slowly. When you see the solder ring that's it, though most people dab a little extra in at that point. There's no problem doing that if you haven't overheated the joint, which you won't if you turn the torch down and take your time.
3) Again, if you're melting adjacent joints, it's probably caused by too much heat. A wet rag will help, but if the solder does melt it shouldn't be a problem as long as the joint isn't disturbed.

 

[SproutsDad]

sooey thanks a lot, your reply helped a lot.
Would be very grateful for answers to the following please.......
1) Blowtorch Heat - Agreed I need to wind down the torch heat, and maybe get a finer pinpoint nozzle to be more focused, would that help?

2) Melting of solders - When the ring of solder has appeared, if I use an additional dab of solder should it melt straightaway? I'm sure I had problems in the past with having to carry on heating to get it to melt, hence the risk of flushing the fitting of it's solder. Do they all have the same melting point more or less?

3) Soldering Heat pad - Cheap solder heat pads are about £6, would that be any good for working near to plastic pipe? I have put metal sheet near it to help deflect heat, but that can also conduct heat!

4) Soldering Bottom to top or? - is there an order to solder joints or parts of the joint? Do I work vertically bottom up or top down?

Thanks again for your help.

 

[JohnD]

you are working on dry pipes, aren't you?

 

[oldbuffer]

1) Heat. You don't need much heat to solder 15mm pipe and fittings. I use a Rothenberger SureFire 2 and its about right when the flame is just "hissing", just after a silent flame as you turn it up.

2) Solder. You shouldn't need any more, although a lot of people like to add a touch "just in case". Providing you are using unleaded solder, and the fittings are unleaded then the melting points are much the same. (Leaded solder and fittings are also matched). If you add some, it should melt straight away. Using Yorkshire fittings its easier to heat the pipe first, moving the heat along to the fitting. Keep the heat on the move. The internal solder is already stuck to the fitting, and you want it to melt and run onto the pipe. Make sure pipe and fittings are really clean of dirt, grease, tarnish etc, flux the pipe, insert and twist if possible to spread flux. After insertion, wipe off excess flux with dry cloth, solder, then, when cool wipe off really well with a wet cloth.

3) Heat pad. The cheap pads are OK, but don't last long. If you really can't move the plastic, wrap it in a sopping wet rag, then a piece of metal (aluminium is a good heat conductor and easy to work), then the heat mat.

4) Soldering Direction. The theory is to work from bottom to top as heat rises, but it doesn't really matter for practical purpose. However, try not to overheat one part of, say, a T junction while soldering the other legs. I try and do the most awkward leg first to get it out of the way, then the easier ones as there is less risk of keeping the heat on too long.

As said above, the pipes must be absolutely dry. A splash of water will ruin any soldering effort.

It sounds as if you don't have too many joints to make, but that they are awkward. Might be worth getting a plumber to do it rather than spending more on solder, mats, fittings etc.