# No-Hub cast iron joints



## plumber tom (Aug 10, 2014)

Has anyone ever put tar on their cast iron or MJs? At my current site, the base building plumbers have put it on some of the joints, but not all of them. :huhWhich then spreads everywhere, since it seems to be a soft sort of roof-patch tar :wallbash Do they know something that I don't, or is this just poor workmanship?

On a side-note, it's especially fun to hydro-test the drainage, and forget to check the existing Fernco on the floor drain - the "tar" seemed to act as a lubricant, causing it to slide apart. :boat:


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## justme (Jul 4, 2012)

I remember doing this on 6" and larger cast iron on a highrise roof drain system 20 years ago, but I was just a helper so I couldn't tell you if it was spec'd or not.


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## Nathan901 (Feb 11, 2012)

Gasket making material is good on larger pipe.


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## CT18 (Sep 18, 2012)

I have in the past, cant remember what it was called. We used it in a facility where they were concerned with major temp changes.


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## 89plumbum (May 14, 2011)

Yeah, about 22 years ago we did a school where all sanitary and storm was put together with heavy duty mission bands, 6 clamps on each band (they may have been called something else). On underground almost every joint leaked. 

Boss called rep. Rep says we must use seekonk torque wrenches only. Buy several pair. Tighten and refill system. Almost every joint still leaked.

Rep says we must be getting dirt in the joints, so boss says come give us a demonstration. Two guys in polo's come out monday. They have us dig out around one coupling in an open area. They have 2 buckets of clean water. One for dipping the rubber in and the other to pour around pipe. They tighten new band and it still leaks.:laughing:

They say they have to do some research:laughing: Then they come back and say continue doing the dipping and also start using the gasket tar. 

We found if you tar it and tighten it all the way you will still have leaks and problems with slippage. You have to tar it, then snug the band just enough to hold it in place. Then come back the next day and torque it off. We actually got pretty good at it by the end of the job. Thankfully it was my first and last experience doing a job like that.


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## plumber tom (Aug 10, 2014)

89plumbum said:


> Yeah, about 22 years ago we did a school where all sanitary and storm was put together with heavy duty mission bands, 6 clamps on each band (they may have been called something else). On underground almost every joint leaked.
> 
> (...)
> 
> We found if you tar it and tighten it all the way you will still have leaks and problems with slippage. You have to tar it, then snug the band just enough to hold it in place. Then come back the next day and torque it off. We actually got pretty good at it by the end of the job. Thankfully it was my first and last experience doing a job like that.


Yes, I have also found that if you tighten MJs most of the way in, and then come back later to finish tightening later, it works best. Otherwise, later on it feels almost loose, even without tar. :blink:

Thanks for the detailed reply; glad to hear I'm not the only one who has had issues with this. The other issue I have found with cast is having hairline cracks in the pipe- hopefully this isn't a sign of problems to come in the now-undamaged pipes, such as splitting. Funny how quickly things show up with 8' head on a hydo-test!:thumbup:


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## bct p&h (Jan 19, 2013)

plumber tom said:


> The other issue I have found with cast is having hairline cracks in the pipe- hopefully this isn't a sign of problems to come in the now-undamaged pipes, such as splitting. Funny how quickly things show up with 8' head on a hydo-test!:thumbup:


You should know if cast is cracked or not before you install it. When you snap cracked cast iron pipe it makes a different sound. If you are installing a full 10' you can tap it with something metal, pliers or hammer, and hear the difference between a solid pipe and one that has a crack in it. 
Cracked pipe has a very dull sound to it when you compare it to a good pipe.


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## stillaround (Mar 11, 2009)

This makes me feel better.....we did a Sbarros years ago on 15 ft ladders over a mall dress shop lead and oakum with not a few leaks... and I moaned because the mall was no-hub and I thought I would have been spared the misery of carrying ladles up a ladder etc....so its tar or crack stick ...pick your poison


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## dhal22 (Jul 30, 2010)

We used a liquid sealant a few times when I did high rise construction back in the late 80's/early 90's. Once the sealant dried it was a rock solid connection. It helped prevent blowouts in multi floor testing.

Maybe this product? I'm not sure, too many years ago.

https://www.blackswanmfg.com/index....old-solders-and-lubricants/113-no-hub-sealant


David


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## justme (Jul 4, 2012)

dhal22 said:


> We used a liquid sealant a few times when I did high rise construction back in the late 80's/early 90's. Once the sealant dried it was a rock solid connection. It helped prevent blowouts in multi floor testing.
> 
> Maybe this product? I'm not sure, too many years ago.
> 
> ...


Thats exactly what we used and I spoke to my father and he said exactly the same thing about it preventing blowouts.


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## Flyout95 (Apr 13, 2012)

No hub sealant is a pain in the balls.


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## Tommy plumber (Feb 19, 2010)

Glad I read this thread. Sealant on no-hub is news to me. Not saying I don't believe it. We always used just the no-hub bands on pipe and fittings and we never had leaks like you guys are talking about. And I've done some roof drains in no-hub. The roof drains were 8" or 10" downstream all without the lube.


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## Redwood (Sep 8, 2008)

bct p&h said:


> You can tap it with something metal, pliers or hammer, and hear the difference between a solid pipe and one that has a crack in it.
> Cracked pipe has a very dull sound to it when you compare it to a good pipe.


Good pipe rings and bad pipe just goes thud....


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## dhal22 (Jul 30, 2010)

Flyout95 said:


> No hub sealant is a pain in the balls.


It's messy for sure. I like the ability though to rotate your fitting after you've torqued the band properly.


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