Fernco coupling leak. Concrete to ABS

[wallywa]

Recently had to redirect sanitary sewer line for home addition. Current Sewer is 4" concrete pipe. Purchased Fernco coupling 4" concrete to 4" ABS. Now that the work is done, Fernco couplings leak at the concrete connections. I put 60 in/lbs on the clamps. Cleaned concrete (which is more like exposed aggregate due to age). I'm guessing the seal is compromised due to the concrete pipe surface. Can I use some type of sealant that won't interact negatively with the rubber to fix this leak? Thanks.

 

[Breplum]

If you used a four band expensive shielded adapter it shouldn't happen. Fernco RC 5000 series.

 

[Sponsor]

 

[John Gayewski]

You could try black swan.

 

[wwhitney]

As a novice, if the cause of the leak is that the concrete pipe is so rough the rubber can't seal, I would be inclined to try to create a smooth sealing surface on the pipe with a fine grained cementitious patching compound. E.g. Cement-All. The other suggestions might be easier/better.

For the OP: black swan is presumably this stuff: https://www.blackswanmfg.com/Category-04/No-Hub-Sealant.HTML

Cheers, Wayne

 

[Jeff H Young]

I used the black swan its sticky and messy so gotta be good ! That or the shielded 4 band might be better , it might be the wrong band too you are using