How to cut this pipe?

[mike42]

In case it helps anyone else going from a seemingly impossible situation, this great forum gave me no less than three options ! In the end I ordered a wire saw online (very cheap) and it was very easy to use to cut this but hard to get a square cut. So I leveled it out by wrapping some masking tape around then trimming with the dremel. Putting a nice bevel on it was beyond my abilities (given it was sunk well below the joists) so I used a coupler (floplast from screwfix) that has solvent weld on one side which slides up the pipe quite easily.
I haven't completely finished yet (yes I'm slow!) but now facing the challenge using slip couplers (ring seal/pushfit) because even when the pipe is lubed up with silicoln they really don't want to budge. I've taken to tapping them with a lump hammer - that seems to work. You would have thought the best and cheapest solution would be to use a solvent weld slip coupler (i.e. a bit of plastic pipe slightly bigger diameter than regular pipe). Something like https://www.jtmplumbing.co.uk/pipe-...t-weld-soil-slip-coupler-double-socket-p18708
One issue I have with that is I don't know whether once the solvent glue is applied, how easily it will slip up and down?

So what I'm about to do (maybe a bodge - eeek) is to close up the pipe so that well above (500mm) above the branch I'm replacing, where the pipe is dry, the pipe inside the coupler won't be pushed home into the middle of the fitting but only about 10-20mm beyond the seal.

 

[Hugh Jaleak]

Solvent starts to melt the plastic on application, I really wouldn't try to fit a solvent slip coupling, and I think it would take a brave Plumber to do so! Lubricate the seals, and the bevelled edge of the pipe, and ring seal fittings should move fairly easily. A bit of gentle persuasion with a hammer if needed.

 

[mike42]

Solvent starts to melt the plastic on application, I really wouldn't try to fit a solvent slip coupling, and I think it would take a brave Plumber to do so! Lubricate the seals, and the bevelled edge of the pipe, and ring seal fittings should move fairly easily. A bit of gentle persuasion with a hammer if needed.

Well it turns out you;re a 100% right there. Its all done now but the only solvent weld I used was at the very bottom where I used the grey version of https://www.screwfix.com/p/floplast-sp124-single-pipe-coupler-black-110mm/62966.
Without glue this connector slid onto the my pipe very easily but as soon as I added glue I struggled to push it home never mind twist it and think I only got it to about 5-10mm away from the lugs before the glue started to bite! I should have had a hammer handy..... I have a feeling I used too much glue....

Anyway, I've now tested both new branches with a hose and it seems leak free. Of course I can't check if the higher up fittings I used to close the pipe are air tight but I'm certain the pipe goes past the rubber seal (even if they're off the lugs by some distance). The pipe is also pretty rigid.

Thanks again for your help Hugh.

 

[Hugh Jaleak]

Can never use 'too much' solvent weld as such, (should always wipe excess off as part of making the joint), too little may cause the joint to leak, then you've the hassle of either trying to seal it, or cutting that section back out to redo it, as you haven't got a hope in hell of getting back apart to add more glue....

Ideally once the pipe has been pushed 'home' into the fittings, you should withdraw it slightly to allow room for movement. Terrain used to be a big manufacturer of solvent weld soil pipe and fittings, (one local guy never used anything else), they used to offer an adaptor kit, basically a rubber seal and a clip on 'lip' that converted a standard solvent coupler into an expansion joint, by converting the top half of the fitting to push fit.