Drain plug in copper waste bend leaking!

[Des333]

I have an old handbasin with a leaking drain plug, threads broken. The bend pipe is copper which is fixed into a pipe running throught the wall into the drain pipe, this seems to be lead soldered into the waste pipe which I presume is lead. The bend pipe is 1 5/16" outside diameter. I've stripped the paint from the pipe to make sure it's not split and seems ok.
What is the best fix or replace for this setup. I'm not a plumber but competent DIY but I don't really want to try and remove the bend pipe from the pipe (lead) going through the wall.
Can I get a new plug, if so where. If a plug is not available would sealant or similar cure the problem (tried Araldite resin in the past on other pipes and found it leaks after a while).
Any idea of the thread type?

 

[dilalio]

Clean it up and try some loctite 55 (thread with liquid PTFE wrapped around it).

 

[Des333]

Thanks for that Dilalio, I've uploaded a picture of the plug and you can see there is very little thread depth and the thread is in very poor condition so there may not be enough thread to tighten and seal. Worth a try though so thanks.

 

[Lower]

Just solder the plug permanently in place.

 

[Des333]

How do I solder the plug in place? I can't remove the pipe without messing up the outer wall connection. Appreciate the support.

 

[oldbuffer]

The thread is most likely to be BSP, probably 1/2" BSP. The 1/2" refers to the inside diameter of a pipe and not the outside diameter of the thread. Over the threads diameter is just under 21mm for 1/2" BSP. Something like https://www.bes.co.uk/1-2in-flanged-plug-with-undercut might well suit.

As a (temporary?) bodge, file the remaining thread off the old plug, fit a new sealing washer, and secure in place with a jubilee clip around the U bend and under the plug. Use some packing in the U bend to avoid the clip cutting into the copper.

 

[Des333]

Thanks for the information posted above. It seems having stripped the paint there are two holes about 1/8" diameter in the pipe, the paint was probably sealing all the leaks. As a temporary solution I'll try to solder the holes but I think the pipe will have to be replaced so it looks like I'll have to remove the bend from the lead pipe in the wall.

 

[Nige F]

Where does the lead pipe go ? outside to a hopper/ it may be easier to renew the lot in plastic

 

[rules&rulers]

That plug can be bonded back in with 2 part epoxy resin filler/glue.

The plug socket looks like it has an uneven mating surface,file this square/flat.

Car body filler or 2 part wood filler.same stuff.

Filler needs to be spread inside the internal threads,around the plug flange and plug threads,screw it in so the flange meets the square/filled surface,smooth the excess around the flange,support with a cable tie until set.

Has to be done in about 25 seconds,otherwise its all bo??ocked up.

This remedy works,

 

[Lower]

How do I solder the plug in place? I can't remove the pipe without messing up the outer wall connection. Appreciate the support.

Just clean the plug and the area it sits in back to bare metal and solder it in place in exactly the same way you would solder a yorkshire fitting. use plenty of flux and don't over heat it.

Soak a rag in water and tie it around the pipe close to the outer wall connection to stop the heat transfer.

 

[Madrab]

I'd be tempted to try a 1/2" one of these 1st, will probably be a brass lining in that bend. If not and it is copper then it may cut itself back in quite easily. Then a bit of tape or thread/threadloc

 

[Des333]

Thanks for the replies,
Nige F, the lead pipe is through the wall and drops into a hopper. You may be right about replacing it with plastic just dont really want to get into removing the lead seal in the pipe and the outside pipe.

Rules, the plug does look a bit uneven this is the old fibre seal, I have cleaned this up and it okay but not enough thread to put a new fibre washer in place I've left the resin/filler remedy as the as the last resort, as you say its got to be done quickly and once done thats it, right or wrong.

Lower, thanks for the help on the soldering, I'm going to give this a go on the small holes and then the plug. I'm ntrying to get a new plug which may solve this but the pipe must be in a bit of a state to have these small holes and no doubt there may be more. Tempted to try araldite??

Thanks to all for the advise,

 

[dilalio]

If it goes into a hopper - change it all to plastic and be done with it.

 

[Madrab]

Thanks for the replies,
Nige F, the lead pipe is through the wall and drops into a hopper. You may be right about replacing it with plastic just dont really want to get into removing the lead seal in the pipe and the outside pipe.

Rules, the plug does look a bit uneven this is the old fibre seal, I have cleaned this up and it okay but not enough thread to put a new fibre washer in place I've left the resin/filler remedy as the as the last resort, as you say its got to be done quickly and once done thats it, right or wrong.

Lower, thanks for the help on the soldering, I'm going to give this a go on the small holes and then the plug. I'm ntrying to get a new plug which may solve this but the pipe must be in a bit of a state to have these small holes and no doubt there may be more. Tempted to try araldite??

Thanks to all for the advise,

I'll just get me coat then will I

 

[Madrab]

Araldite won't work for pinholing as you really need to coat the whole thing for it to take properly. If you coat it completely in thickish polyurethane/boat varnish tho that should seal it up, if it's pinholed. A lot of effort though for an old waste, much easier replacing it but I like the idea of trying to keep it as it is period and personally I like that look, especially with it all cleaned up.