The old 68mm to 63mm down pipe problem.

[dal5band]

I am removing a water butt with a diverter thing in the down pipe. I found that the upper pipe is 68mm ( having been upgraded inthe past) but the lower pipe below the diverter is the old 63mm. I notice that a 68mm pipe will fit over the old 63mm but it is a loose fit. Could I solvent weld this and achieve the conversion ? Then continue with 68mm fittings above.
Does the solvent weld cement stick to the black downpipes ?

PS cannot replace the 63mm as it goes into the ground.

 

[Ian H]

How far into the ground?

 

[dal5band]

Job done ! I put a piece of 68mm over 63mm pipe with weld cement. Further sealed it with some old mastic. Left enough 68mm pipe above the joint to take a 68mm m/f joining socket. The downpipe goes into the socket, with a little adjustment (cuttin
You can see where the old water butt stood on the raised slab.
The 68mm is quite a loose fit over the 63mm pipe so needs to be held in place while the solvent cement sets. Hence the extra matic seal just make sure , a few hours later.

 

[Dave4290]

@dal5band I have the same issue and was looking for a solution. I have old 63mm pipe going underground into a drain. Have bought new guttering and downpipe which is 68mm. As you say the 68mm new pipe fits over top of 63mm but is slack.

Is this what you mean by a 68mm m/f joining socket?

You would think there was a ready made 68 to 63mm reducer ?

Update .... just found this 68-63mm