Cast iron rainwater pipe socket removal

[d49xc]

I’m trying to remove a standard 3inch 'cast iron' rainwater downpipe socket from the adjacent section.
Pipe loosely fits inside socket end of next section and gap between sealed with putty. Over next 80 years the whole lot expands and rusts solid and is extremely difficult to remove without cutting the socket off as I know from others around the house.
Picture at https://copy.com/HA0EtE8vDZvd
As you can see from picture next section with the socket on disappears down into ground adjacent to a large bush so I really do need to remove the bend section without breaking the socket.
Somewhere below that the soakaway/bottom bend is blocked with roots/muck…hence the issue - I'm hoping I'll be able to water-jet the whole lot out once I get unrestricted vertical access from the top.

So far I’ve tried digging out as best as I can the putty sealing the gap between the pipe and socket. I’ve tried stuffing a load of rust releasing fluids down gap.
Tried the usual “not too much force”. Tried a bit of heat but I can’t really get a big enough temperature differential between inner and outer to release it. So far the pipe bend is totally solid and immoveable within the socket.
I’m rather running out of ideas……

The “final solution” of course is to cut off the bend level with the socket top and then cut away from inside the pipe the remains of the cut-off section from within-side the socket. Given that the inside is less than 3” diameter so too small for an angle grinder to get inside this isn’t going to be easy either.

Fortunately time is not an issue as I’ve diverted the rainwater elsewhere temporarily so if it takes me a few months on and off so be it.

Anyone got any suggestions?

 

[MatthewC]

I saved a lot of similar expense when my mate Chris managed to dig out the lead and then the caulking when I had to replace the branch for the foul outlet. I suggest you try to continue with the digging out as there might be caulking lower down which would help?

Alternatively, you could cut the existing socket off with the elbow section as it is possible to buy a replacement eared socket (see http://www.rainclear.co.uk/index.asp?ps=4|12&ct=6&cat1=2&cat2=10&t=downpipe+) for a small sum (£12.07 + VAT). That would just require removal of some more concrete and then a careful cut (grinder and hacksaw) close to the wall.

 

[Lime]

Heat and a lot of it should eventually release the joint.

 

[Flyfisher]

Are you sure the joint has been sealed with putty? I thought lead was commonly used for such seals, in which case I agree with Lime that plenty of heat is going to be required. Not so much for any differential expansion reasons but simply to soften the lead.

The good news is that the angle of the pipe will allow plenty of rotational force to be applied so I'd use a substantial leather gauntlet to grasp the pipe and apply some 'wiggling' force while using a blowtorch to heat the joint. Try not to localise the heat too much otherwise the cast iron might crack due to thermal stress - need to gradually heat the whole joint really.

 

[DJH]

Joints in cast iron rainwater pipes were seldom caulked with lead or anything else for that matter. There's not enough room between the collar and spigot for a start and there was no need to seal the joints as there would be no foul smell emanating from them as from a soil and vent pipe. There isn't room in the joint for caulking chisels for a start...



Occasionally putty, or something similar, was used maybe to keep the pipe in an upright position along with a small wood or lead wedge (usually a rolled up bit of sheet lead) or to stop any movement or rattling taking place. I think the chances are that it's putty that's sealing the joint and chipping away with a thin bladed chisel or screwdriver is your best bet.

Doug

 

[Flyfisher]

Ah, I was probably thinking about foul drainage then. Would heat loosen up putty perhaps? Even if a small amount of movement could be gained, the joint could then probably be 'wiggled' into submission.

 

[d49xc]

Thank you for the replies and suggestions.

If the other downpipes assemblies around the house are to go by it is just putty in the joint - and rust!
(there may be initially some slivers of wood put in to centralise the pipe in the socket - which is what I did when previously replacing sections before puttying them up.
I've never had to take out a soil pipe so I've no idea if they are lead caulked as well.
I've lived here for decades and I vaguely recall soil pipes might just be done with hemp and putty sealing the top - and then paint over the lot.

In the past I have wanted to get two 6ft sections apart because one section had rusted though on the back side.
Sometimes the join comes apart with a bit of digging of the putty out.
On a couple of occasions the join had effectively 'become one'. Running an angle grinder down the outside of the socket to release the clamping force did not help to release the joint and I had to make two cuts to take out a segment of the socket before the inner would release.
Carrying replacement 6ft sections up ladders and then holding in position with one hand while hammering in the pipe nails with the other is at my energy limit - a 6ft length of 3" pipe weighs in at 13Kg for those not familiar within them.

I agree that if I can get just a bit of movement, on past basis, that will give enough wiggle room back/fro to get it out - I've used my chain wrench before to help.
So far my attempts at using a bit of force (via a short scaffold pole inside the bend) with much care results in slight movement of the whole assembly as it goes down into the ground. As I must not break the effectively inaccessible join to the clay pipes leading off the the soakaway somewhere I'm being very careful.

I will continue my struggle............I'm using a self modified plasterboard saw to dig the putty/rust out.

 

[Lime]

................
So far my attempts at using a bit of force (via a short scaffold pole inside the bend) with much care results in slight movement of the whole assembly as it goes down into the ground. As I must not break the effectively inaccessible join to the clay pipes leading off the the soakaway somewhere I'm being very careful.

...........

That slight movement indicates that the damage has been done.
the joint below is broken.

 

[Flyfisher]

Or, possibly, hopefully, that the underground joint is loose? Possibly by root penetration that may have caused the blockage in the first place?

I notice that the above ground fixing point is not fixed to the wall. It might be a good idea to fix this to the wall (rawlbolt or similar?), which should stop the underground pipe from moving as pressure is applied to the bend.

I suspect that a spade may soon be required for this job.

 

[Lime]

Or, possibly, hopefully, that the underground joint is loose? Possibly by root penetration that may have caused the blockage in the first place?

I notice that the above ground fixing point is not fixed to the wall. It might be a good idea to fix this to the wall (rawlbolt or similar?), which should stop the underground pipe from moving as pressure is applied to the bend.

I suspect that a spade may soon be required for this job.

I'm a simple soul and would consider the joint broken if it was only loose, with no structural damage to either pipes, because whatever now flowed through the pipe could leak out!

I agree about the use of a spade.