Using instant cement to join PVC and plastic pipe?

Sprinkler · Dec 14, 2008

I want to join a 110 mm PVC pipe to an old plastic toilet sewer pipe under the ground. The thing is the PVC pipe is 110 mm and the internal size of the plastic pipe is around 120mm, so I was thinking of just inserting the smaller PVC pipe about 4 or 5 inches inside the bigger pipe, and using normal builder's instant cement to fill in the space. First, I would pack in some tissue paper to stop the cement from going down along the pipe, leaving about 4 inches for the cement.

Would this solution be ok? Or should I use some other kind of cement? I think that silicone may not be very permanent... In any case I intend packing in normal cement all around the pipe, which I suppose would also help to seal everything? Thank you.

ExpertPlumberSVC · Dec 14, 2008

Your Solution is Acceptable

I believe that your solution is acceptable. I have in the past used hydraulic cement to fill the voids around a piece of ABS pipe that I had inserted into a clay main drainage pipe. When the city Inspector arrived ... He O.K.'ed the work and we all were pleased.

Sponsor · 2022-01-29T12:20:58-0800

Sprinkler · Dec 14, 2008

Great! So I don't suppose the instant cement would cause any problem by possibly expanding when it dries out...but in any case I suppose it could expand horizontally along the pipe, if it wanted to...

Kingsotall · Dec 14, 2008

They make clay to plastic no hubs.

Seems like the connection we are devising with the cement will inhibit blockages down the road. I think I have the flow figured in the right direction.

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Sprinkler · Dec 14, 2008

It's a waste pipe from a toilet, so the flow is only in one direction. And I think the pipe has a slight downward fall / inclination.

Gary Swart · Dec 14, 2008

It might work, I can say for sure that it won't. BUT, I'd still use a transition connector that is code approved for joining dissimilar pipes.

Sprinkler · Dec 14, 2008

the main pipe's been in the ground maybe 40 or 50 years - looks like white plastic.. I think (?) it's ok to use the instant cement - it's basically to seal odours, since there is a fall on the pipe anyway. The only concern would be if the cement might interact and damage the plastic or expand and cause cracks in the pipe....?

Sprinkler · Dec 14, 2008

And how about if I inserted the smaller pipe and put a rubber accordion ring around it (type use on toilet outlets), so that I can press fit it into place and then bury everything in cement? Would the rubber ring be permanent?

Gary Swart · Dec 14, 2008

That pipe may be transite (spelling ???) which I think is a type of asbestos. I think it is a very durable pipe and even if it is asbestos, buried it would do no harm.

Sprinkler · Dec 14, 2008

well...doesn't look like typical asbestos..it looks plastic to me, same thickness as pvc tubing. I assume those rubber accordion rings would be relatively permanent if they are used on toilet outlets - though i don't know if they can be buried in cement. But in any case the outside of the joint would be covered in normal cement, which would presumably act as a seal as well?

Gary Swart · Dec 14, 2008

If the pipe is as thin as you say, then it is likely PVC. For underground connections, a neoprene sleeve by Fernco would work fine. You need to get one that is made for the sizes you are joining. You may have to go to a real plumbing supply house rather than a home improvement store.

Sprinkler · Dec 14, 2008

Here is a photo of the waste pipe. There is a PVC patch on it from a few years ago. I have temporarily inserted the female side of an elbow joint, which shows the gap more or less. Do you think I could just use PVC cement or some other sealer...silicone? It's delicate work taking away the surrounding cement without breaking the pipe...

ExpertPlumberSVC · Dec 14, 2008

Certainly ... Yes

I agree that whatever you use to seal your drain depends upon you providing a seal that does two main things ...

# 1) you MUST seal sewage against leakage and # 2) you must attempt to avoid penetration by root growth

use your best discretion when choosing your method.

sometimes the piping of your specific situation ( accessibility; for instance ) may certainly be a factor in deciding how to accomplish a task.

The technique or materials you ultimately decide to use should come rather easy now, because ALL of the preceding commented solutions which I've seen here are each VALID solutions ...

MERRY CHRISTMAS, and thanks ...

I just discovered this site today ... I am impressed and BTW ...

MY Question was answered here ... I Googled it and here I landed ... Thank you all ... Tomorrow I shall repair Marylin's shower

Gary Swart · Dec 14, 2008

PCV "cements" aka "glue" is neither cement nor glue. It is a solvent that briefly melts the surfaces of the pipe and fitting being joined and when the two pieces are slipped together, the two surfaces combine to create a weld much like a metal weld. Moreover, the two pieces being joined must fit since the solvent weld does not fill in a void. This fit is so tight that it requires the pieces to be coated with the solvent before they will slip together. In other words, they can not be dry fit.

Sprinkler · Dec 15, 2008

So I cant use PVC cement, even if it does adhere to the plastic pipe, because the fit is too loose? I was just going to experiment trying a drop of PVC cement on a piece of the plastic pipe to see if it really sticks, but as you say if it is not a tight fit, there is no point. I also agree about the accessibility - since the access to the joint is very problematic, I thought that even inserting the elbow as in the photo with no sealant, but digging a bit more cement from around the underside of the joint, then I would be able to pack in lots of instant cement, which I assume would also give a pretty good seal, even if the seal is "outside" the joint. I would first put some tape or something around the joint to stop cement going inside the pipe. How about that as a possibility?

Kingsotall · Dec 15, 2008

Chip out around the pipe (about 8") with clearances of atleast 3" all the way around the pipe. Get a measurement of the ID and OD of the pipe, take that measurement to a plumbing supply house, have them get you the appropriate size no-hub coupling, having let them know of the size of pipe you plan to transition to. They might even have a more appropriate size pipe then the street ell you have now.

Sprinkler · Dec 15, 2008

Just asked today in the main plumber suppliers in this area - they never heard of anything like a Fernco coupling. I asked a plumber who was in the shop. He said I should use chemical filler to seal the joint - looks like a silicone container, and it's usually used instead of rawl plugs. Then he said I could put a sleeve of PVC over the joint, which means you use about 2" of 110mm pipe, cut it, and heat to make it pliable so that it can be wrapped around the new joint and stick it with PVC glue. Well, I think it's worth a try. Then I would fill in all around with cement and small stones. Not sure if I should first use some instant cement to cover the joint, because I imagine it is more water resistant than normal cement?

hj · Dec 15, 2008

pipes

There are connections to join any two types of plastic pipe together, but NONE of them are cement of any type.

Redwood · Dec 15, 2008

I don't know what kind of plumbing supply house you went to but....
This below is a picture of a Fernco coupling...

They come in different sizes for different types and sizes of pipe.

Sprinkler · Dec 15, 2008

Please see the photo. Do you think this idea would work? My problem is that I can't seem to get the proper fittings in this part of Spain, and don't want to wait to order by mail.... Another option would be to make part "A" and part "B" equal in size, cut precisely to cover pipe "C"....Thank you.

Using instant cement to join PVC and plastic pipe?

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