How to connect cast iron pipe to toilet?

[yartin]

I have cast iron pipe in a toilet, I had a plumber few year ago who changed the pipes, he used a black connector between cast iron to pvc but it does leak sometimes.
What is the best product to use? Basically to connect the the toilet to the cast iron pipe.

[toolbox]

Usually it is a toilet pan connector like these.
https://www.screwfix.com/c/bathrooms-ki ... econnector
Just a case of seeing which one suits your lay out.
As long as the pan is near the iron one of those should do.
If he was putting in a bit of extra pvc he may have used one of these, not ideal inside.
https://www.plumbingworld.co.uk/catalog ... er+adaptor
Can you post a picture?

[yartin]

Usually it is a toilet pan connector like these.
https://www.screwfix.com/c/bathrooms-ki ... econnector
Just a case of seeing which one suits your lay out.
As long as the pan is near the iron one of those should do.
If he was putting in a bit of extra pvc he may have used one of these, not ideal inside.
https://www.plumbingworld.co.uk/catalog ... er+adaptor
Can you post a picture?

I was thinking of using the ones in the screwfix link, can I use:
https://www.screwfix.com/p/floplast-sp1 ... hite/12078
or
https://www.screwfix.com/p/mcalpine-mac ... 10mm/98788. ?

I have seen the 4" coupling rubber in black but they won't look nice inside as you said.

I think he has used a what's called cast iron to pvc connector but will put photo tomorrow.

Cheers

[toolbox]

You will need to use the extension in conjunction with a pan connector they come in straight offset and angled versions.
https://www.screwfix.com/p/mcalpine-mac ... 12mm/78806

[yartin]

I think my plumber has used the right connector which is the MCALPINE DC1-GR Finned seal spigot for internal connection to 4"/110mm cast iron, plastic or clay. photo of toilet and mcalpine DC1 attached.
May I need to change the connector and try again?

[yartin]

Flo plast do them too, SP140 adapter as in photo
Can someone tell how far this adapter will go inside the cast iron pipe? The Mcalpine doesn't go very far and seems that's why didn't work for me. This flopast sp140 seem to me goes all the was and the flo past writing in on the connector will be inside the cast iron pipe?! Or may be just upto 1/3 of the grey pipe by the groove?!

I did more reading, these so called cast iron adapters are made of rigid plastic while normal white toilet connectors are made of propylene. I guess for a reason, internal and external use?!
Both flo plast and macalpine cast iron adapters connectors come in black or grey , No white. So for external use.

Also came across this useful video re Sp140 : https://www.youtube.com/watch?v=1HN05T31YlQ

So possibly or defo normal white toilet connectors (internal use) should do the job?

[yartin]

You will need to use the extension in conjunction with a pan connector they come in straight offset and angled versions.
https://www.screwfix.com/p/mcalpine-mac ... 12mm/78806

I think this works but won't look nice.

[yartin]

I think my plumber tried to be a bit clever, he didn't need that black connector, further research proves things are very simple and straight forward. just use standard fittings. Standard MAC-EXTA will do as says in specs: "Available for 3"/75mm, 3½"/90mm and 4"/110mm PVC-U and cast iron soil pipe diameters (internal)"

The link: https://mcalpineplumbing.com/wc-connect ... ion-macfit
as per photo.

[toolbox]

Yes but if you push the extention you show into the cast iron you will still need a pan connector to fit in the plain end of the extention.
You could use a flexible connector but it will be prone to sagging in your situation so not a good idea.
The main thing is to ensure the inside of the cast is as clean and smooth as possible. Rubber gloves and some emery cloth are required.
If the inside is very rough you could smear a very thin coat of silicone inside the cast to help the seal.

[yartin]

Yes but if you push the extention you show into the cast iron you will still need a pan connector to fit in the plain end of the extention.
You could use a flexible connector but it will be prone to sagging in your situation so not a good idea.
The main thing is to ensure the inside of the cast is as clean and smooth as possible. Rubber gloves and some emery cloth are required.
If the inside is very rough you could smear a very thin coat of silicone inside the cast to help the seal.

I will use the WC mac fit on the toilet end, photo attached.
Agree flexible connector won't be good idea
Jut the straight and wc connector needed.
Yes a good clean is required of the cast pipe, may be I can use wire brush to clean the inside?

[toolbox]

Yes I have used a rotary drill wire brush before but beware of splashes! Yuck!

[yartin]

Yes I have used a rotary drill wire brush before but beware of splashes! Yuck!

I meant a small manual wire brush, to bin it after the job.

[yartin]

I am now thinking to use Mcalpine Straight Flexible WC Connector, as in pic. It's one piece which means go straight in and no messing about, instead of having 3 pieces. If the flexible part of the connector don't look good, I can buy 110mm white straight pipe cut in two halves and fix over the flexi part!

Any thoughts?

[toolbox]

Will work but remember as I said flexible ones can dip causing problems.

[yartin]

Will work but remember as I said flexible ones can dip causing problems.

So is it better to buy the longer version than I need so it will be more dense and less stretch hence less likely to dip?
Plus if I cut a straight 110mm pipe into two halves and fix on top and bottom of the stretch part to add strength.