Donut Sizing For Cast Iron Pipe

[brb]

Hello! Just wondering if anyone has a idea on what size donut would work to connect 2in pvc to the hub in this cast iron main stack. I have not removed the lead and pipe yet, but did take some measurements. I think it is 3 1/4 I.D. I called Fernco and they only make a 3 in I.D. donut. Does this taper to the point where the 3in will work? Would love to have all this sorted before I remove it. Thanks for the help!

 

[Jadnashua]

The donuts are designed to convert between the CI hub and plastic pipe. Nominal 3" PVC or ABS is 3.5" OD (3" ID). The variations on the donuts is in their OD, which must be the right diameter to make the seal. SO, not exactly sure what you are saying.

 

[Sponsor]

 

[brb]

jadnashua thanks for the reply. Finally getting back at the project after the holidays. I realize that what I was asking was not worded very well. I ended up removing the galvanized pipe coming into the main stack that was leaded in. I am trying to install a 2in pvc pipe into that part of the hub. I measured a ID of the main stack hub at 3.25. I purchased a Fernco 3x2(33U-205) donut but the OD of that measures 3.75 and I really don't see that fitting. I then picked up the 2x2 fernco donut (22u-205) thinking this would be the ticket but it is to loose. The OD of that donut is right at 3in. I called Fernco and they said that they don't have anything in-between those dimensions. Any help is greatly appreciated!

 

[Smooky]

This might work:

http://www.homedepot.com/p/3-in-Service-Weight-Cast-Iron-Hub-x-2-in-Sch-40-Plastic-Compression-Donut-P33U-205/100123301?cm_mmc=Shopping|THD|G|0|G-BASE-PLA-D26P-Plumbing|&gclid=CMrpp8jPndECFYSLswodVJQCDg&gclsrc=aw.ds


Some pipe size info
http://www.engineeringtoolbox.com/cast-iron-soil-pipe-dimensions-d_1751.html

There are donuts at the bottom of this link and you can click on the dimensions of each one:
https://www.plumbingsupply.com/flexibleconnectors.html

 

[brb]

Thats the one that I have that is a OD of 3.75in. I tried to soap it up and pound it in but I think it's to big to fit into the 2 xh hole. If people have fit it in then I can rig up a press but it seems way to big to compress.

 

[Smooky]

You could cut the 3” cast iron pipe and use a banded transition fitting to connect the PVC
http://www.supplyhouse.com/sh/control/search/~SEARCH_STRING=3" x 2" ProFlex Coupling Cast Iron PVC


In your picture I don't see any 3" pipe. It looks like your cast iron Y says 4" and 2"
The branch pipe looks like it might be smaller.

 

[Kreemoweet]

What about the Fernco 22UX-205? You didn't mention that one, and it's extremely odd that the Fernco people
didn't either. I recall using donuts made by companies other than Fernco in the past (because the Fernco's didn't
fit), but I can't find much online info about them. If you have any real plumbing supply businesses in your area, they
might just have exactly what you need, sitting on some back shelf collecting dust.

 

[Jadnashua]

You used to be able to see a list of available donuts on Fernco's website...if it's there, I didn't find it! Their instructions say that the sizing must be within 1/32" to make a proper seal. The do not indicate that I saw, how much they expect the thing to compress while installing it. THey claim to make hundreds of sizes to account for the variations across the foundries.

 

[FullySprinklered]

I've done just a very few gaskets of this type. None of them were user-friendly. I remember my last one, keep in mind that each preceding one was a major struggle, and it came down to this.

I got my second wife to go in the drug store for me and purchase two tubes of store-brand personal lubricant. She was a nurse and had no qualms about this. Next day I arrived on the job ready to proceed with my connection.

There was a 3x2 iron wye fitting at floor level under the three stacked bathrooms above, in the basement level slab. I had cleaned out the two inch leg of this vertically oriented fitting and needed to stub out 2" pvc to catch whateveritwas from above.

Utilizing methodology that had worked for me before after several difficult and unrewarding episodes, I put the service weight gasket half-way into the iron bell on the two-inch leg, beveled off a two-foot piece of 2"pvc and stuck it into the gasket as far as it could go. All contact surfaces were liberally slathered with store-brand lubricant from Rite-Aid pharmacy.

I put my back against the vertical three inch iron pipe, with the two-inch stub between my legs and pounded the pvc into the fitting with a cinder block.

Perfect. I cut the mutilated end of the 2"pvc off and installed a coupling there and carried on.

 

[brb]

Thanks for all of the replies. It really seems like a odd ID size for the pipe. I have been measuring this with a digital calipers so I know my measurements are spot on. When I talked to Fernco they said that it had to be within a 1/8in for a good seal. Probably going to hit up some local plumbing supply houses to see if there is something else. They must have used a ton of this pipe in my area and someone has to have a solution without cutting it all out.

Whatever resolution I find I'll be sure to let people know!

 

[brb]

kreemoweet I think you may be onto something with that Fernco PN. I found in another forum that is for the xh CI pipe. I'll try to find one this week and report back.

 

[Jadnashua]

different foundries, different parts of the country, different years, all will have slightly different molds that created the hubs on their CI pipe. The only thing standard is the actual ID of the main pipe. Since the stuff is heavy, they tend to get it from the nearest foundry. For that reason, it's more likely the local shops will have the donut to fit. FWIW, from the same foundry, they often had two hub sizes, 'standard' and extra-heavy.

 

[brb]

Received my 22x-205 today and it is slightly bigger than the 22u-205. It is still not large enough to make a good seal though. There is a Ferguson supply near me and hopefully they will have something that will work otherwise not sure how to handle this?

 

[Asktom]

Oakum and Black Swan Soil-O would work.

 

[brb]

I assume if I would get a Fernco pipe adaptor that would fit around the outside like I have pictured that would not pass code?

 

[Jadnashua]

I assume if I would get a Fernco pipe adaptor that would fit around the outside like I have pictured that would not pass code?

You're correct...that does not pass plumbing codes!

 

[Reach4]

I assume if I would get a Fernco pipe adaptor that would fit around the outside like I have pictured that would not pass code?

Did you understand asktom's suggestion in #14? It sounds like an ideal solution, don't you think?

 

[brb]

Reach4, I did see that. I feel like at this point it may be my only option. I assume I can use that with pvc or do I have to transition to metal?

 

[Asktom]

Oakum and Soil-o work fine transitioning from a cast iron hub to plastic pipe.

 

[brb]

Should have my oakum and the soil-o friday. I assume I want to pack it 50% with oakum and then pack it as tightly as possible with the soil-o?