Any alternatives to hookup of 4" cast iron sewer drain with a 4" PVC pipe, other than flexible non shear rubber coupling?

Thank you.

Hi Salaka:

I'm not sure I am clear on the question... but if you are asking if there is more than one way to hook PVC to cast iron pipe BESIDES the non-shear rubber coupling or clamp... then there is an alternative.

One example would be to use good old fashioned lead and oakum. Here, you would take the cast iron hub of a length of cast iron pipe and insert a PVC manhoff fitting. Then you would pack oakum around the manhoff until you have about 1" to 1.5" space left until top of the cast iron hub and then you would pour molten lead to fill the joint, let it cool and then pack the lead tight to seal the lead joint. This takes special tools and some pretty good experience to do, but it is an alternative. The molten lead will NOT melt the PVC manhoff enough to melt through the manhoff. This method of joining cast iron to PVC is acceptable everywhere that I know of... ;)

Let me know if I misunderstood this... And please tell me why you are asking this question. Just curious?

MARK

Quote:

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Originally Posted by massplumber2008

Hi Salaka:

I'm not sure I am clear on the question...but if you are asking if there is more than one way to hook PVC to cast iron pipe BESIDES the non-shear rubber coupling or clamp...then there is an alternative.

One example would be to use good old fashioned lead and oakum. Here, you would take the cast iron hub of a length of cast iron pipe and insert a PVC manhoff fitting. Then you would pack oakum around the manhoff until you have about 1" to 1.5" space left until top of the cast iron hub and then you would pour molten lead to fill the joint, let it cool and then pack the lead tight to seal the lead joint. This takes special tools and some pretty good experience to do, but it is an alternative. The molten lead will NOT melt the PVC manhoff enough to melt through the manhoff. This method of joining cast iron to PVC is acceptable everywhere that I know of...;)

Let me know if I misunderstood this...And please tell me why you are asking this question. Just curious??

MARK

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Thanks Mark.

Yep, you got it correct. The reason I am asking this is, I am replacing my cast iron w/PVC. Cracked cast iron pipes. I cannot replace it all, some cast iron remains in the house. The solution the plumber supply house recommended was using the flexible coupling. I am not sure about the reliability of the coupling. Rubber usually dries up eventually and starts cracking. I do not want to be tearing the walls every so often. Besides the damage could extend beyond the walls and celing. Thanks again.

Hey Salaka:

I was wondering if this was the case. I wasn't sure if you were asking a homework question or needed to apply information directly.

In fact, you will have a great job if you use SHIELDED clamps (see below). The trade names are proflex clamps or mission clamps. These are transition clamps and will make up for the difference in thicknesses between the cast iron pipe and the PVC pipe. The rubber will not dry out over time and this really is best in your situation.

You will need to know if you have extra heavy or service weight cast iron pipe (look on hub of pipe and see if you have SV (service weight) or XH (extra heavy)).

Here, you make a clean cut on the cast iron pipe using a sawzall with a bimetal or diamond reciprocating sawzall blade and then use the clamp to transition over to PVC.

The lead and oakum alternative is complicated and done only when required nowadays.

Hope you come back to read this...

MARK

Quote:

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Originally Posted by massplumber2008

Hey Salaka:

I was wondering if this was the case. I wasn't sure if you were asking a homework question or needed to apply information directly.

In fact, you will have a great job if you use SHIELDED clamps (see below). The trade names are proflex clamps or mission clamps. These are transition clamps and will make up for the difference in thicknesses between the cast iron pipe and the PVC pipe. The rubber will not dry out over time and this really is best in your situation.

You will need to know if you have extra heavy or service weight cast iron pipe (look on hub of pipe and see if you have SV (service weight) or XH (extra heavy)).

Here, you make a clean cut on the cast iron pipe using a sawzall with a bimetal or diamond reciprocating sawzall blade and then use the clamp to transition over to PVC.

The lead and oakum alternative is complicated and done only when required nowadays.

Hope you come back to read this...

MARK

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Thanks Mark,

Where can I buy the couplings?

Shielded clamps (last post) can be found at home depot, Lowe's, or menards home improvement stores.

You do not want to purchase a fernco coupling like the one pictured below (1st pic.). These are primarily intended for underground transitions and for quick repair work.

Finally, just to make this even more confusing I actually prefer to use a No-hub x PVC adapter and then use a 4-band husky clamp (see 4 band clamp pic.) for best results. I prefer this method over the shielded clamps as they only have two SS bands which means only one SS clamp on each connection. The 4-band husky clamp, of course, has 4 SS bands and that gives me two SS bands on each connection. The 4 band clamps and the no-hub x pvc adapter can only be found at a local plumbing supply house.

I mention all this now because sometimes the shielded clamps can be a little loose dpending on if you have service weight or extra heavy sewer pipes... never mind that there are variations on these sizes, too.

For best job, as hard as this is to believe, I would get each type of clamp..shielded and 4 band with adapter...and see which one fit best.

Let me know what you discover will you.

Thank you.