change old plastic waste pipe to new metal

happyhero

Hi can anybody help me? My father wants me to help him replace his plastic waste pipes in the alley way at the side of his house. He has 3 waste pipes coming out the wall from 2 sinks and the bath. One of them is metal painted black, the other two are old white plastic. I don't know how old they are but they have gone a funny colour and are very brittle with the odd hole in them now, so really had it.

I said it would be easy to replace the plastic but he is very insistant that he wants to change them to metal like the other one. I tried to measure the diameter of the old plastic pipes and they appear to be 35mm.

So my questions are:-

Did it used to be 35mm or is it just 32mm badly measured by me?

Can I get metal waste easily ie B&Q and all the joints?

How do you put the metal ones together?

And assuming it is plastic coming through the wall, how do I make a watertight joint from plastic to metal?

Any help appreciated.

raymond

I dont think metal waste pipes are made anymore, plastic comes in two different sizes, push together and solvent weld and they are not compatible although you can get a uviversal connector which joins two "similar"sizes.

If I remember correctly, push fit os 32mm od and solvent weld is 32mm id. You also get 40mm for bath wastes.

roswell

you maqy be able to get metal ones from a salvage uyard but reallyt probably cheaper to just get plastic

bestyman

Hi,
Replacement of pipes will be in plastic for waste pipes, metal is not really an option.
2 sizes were used 1 1/2" and 1 1/4". To join the new plastic to the old metal you need a socket that tightens up with nuts. Ask at the plumbers merchant for a Mc alpine socket ( only a couple of quid so buy both sizes). Make sure the metal pipe is cut on a straight smooth section. In some cases a little force is required to get the mc alpine socket on the pld metal pipe.

Another option is to not join to the existing metal pipe but to repipe in plastic completely. This would mean changing the old trap as well and starting from scratch.

Bestyman

happyhero

bestyman wrote:

Hi,
Replacement of pipes will be in plastic for waste pipes, metal is not really an option.
2 sizes were used 1 1/2" and 1 1/4". To join the new plastic to the old metal you need a socket that tightens up with nuts. Ask at the plumbers merchant for a Mc alpine socket ( only a couple of quid so buy both sizes). Make sure the metal pipe is cut on a straight smooth section. In some cases a little force is required to get the mc alpine socket on the pld metal pipe.

Another option is to not join to the existing metal pipe but to repipe in plastic completely. This would mean changing the old trap as well and starting from scratch.

Bestyman

Cheers guys all very helpful. I am going to convince my father that it has to be plastic or we will have a headache.

But bearing in mind the fact that the plastic existing is old enough to perish, could the plastic be 1 1/2"?

It is the usual affair where there is an elbow right up against the wall where the pipe run dissappears into the property. If I pulled this elbow off I may find it is a short bit of 1 1/2" poking out. What would I do here?

Do they do a elbow which will allow me to change from the 1 1/2" to plastic or what would you suggest to do here?

If there is not enough poking out the wall I may have to chisel some mortar out. Hopefully there will be and hopefully it wont be as bad as the outside stuff being as it was inside the elbow. I dont really want to put any converter that is straight on this first and then the elbow as it sounds to me that that will make the whole thing protrude away from the wall a lot.

If the bit protruding is modern day plastic sizes and condition is ok then obviously I wont have any problems, fingers crossed.

Your thoughts please.

plumb1_2

You will find that the pipe will be flush with the wall when you take the elbow/bend off.
As you say the pipes are perished this will be due to the Ultra voilet light, as the plastic will be push-fit(bartol or osma) .
What you will need is a All-Fit elbow, in push-fit and not a McApine(with nuts)
The all fit elbow will then allow you to fit any make of pipe.

bestyman

Hi,
Whats wrong with a mc alpine with nuts???
I would use mc alpine elbow if socket not appropriate.

happyhero

plumb1 wrote:

You will find that the pipe will be flush with the wall when you take the elbow/bend off.
As you say the pipes are perished this will be due to the Ultra voilet light, as the plastic will be push-fit(bartol or osma) .
What you will need is a All-Fit elbow, in push-fit and not a McApine(with nuts)
The all fit elbow will then allow you to fit any make of pipe.

can you give me a link to one or both on the internet please, I have looked and cannot find one.

plumb1_2

bestyman wrote:

Hi,
Whats wrong with a mc alpine with nuts???
I would use mc alpine elbow if socket not appropriate.

Because the poster has already said the pipe is flush to the wall, so when he takes the bend off ,it will not project enough to get a McAlpine elbow on, plus he would also have to chishel some of the Brickwork out to be able to get the McApine to fit, so he is better off getting a Pushfit -Allfit elbow, which will do the job better and he wont have a large and ugly compression(Mcalpine) elbow sticking out from the wall, if intending to do a neat job, and 1 that looks like it not been botched.

Just go to your local Plumbcenter for the materials.