Connecting corroded steel to PVC

[hopkinmn]

I was cutting into an old steel vent pipe to connect a new plumbing vent, when the steel pipe snapped off at the elbow 6" above where I was making the cut.

The elbow is fit snuggly between two joists, so getting a new, appropriately-sized Fernco over the elbow would be tricky. And, I'd rather not cut into the joists if I can help it.

Is there another way to connect PVC to this? Is there anything such as an expansion fitting that would go inside the elbow and expand to seal?

 

[Aih2008]

Hello,

Follow this link, it may fit your situation.

https://www.supplyhouse.com/Fernco-...t-ABS-Coupling-for-Sewer-Pipe-DWV-Connections
Internal diameter should match. Not sure how it would fit inside the fitting, especially that it is a 90.

Only other option would be to cut the pipe and connect along the run between the joists.

I hope it helps.

 

[breplum]

Old galv. Pipe is 100% worth getting rid of.
Aside from a pipe tap, you are sunk…

 

[pasadena_commut]

What snapped here, the pipe screwed into that elbow or the elbow itself? From the picture that elbow (or the remainder of the broken pipe) looks like it is in very good shape, with just a little rust on the inside and plenty of metal.

Is part of the old pipe still stuck in there? Are the threads of the elbow OK?

Anyway, it seems to me that if there is substantial bit of the snapped pipe still in there you should be able to screw it out, probably after soaking it for a while with penetrating oil. If it is just the threads which are messed up, then you could retap it.

Or as breplum suggests, just replace that piece of galvanized entirely. I can see where maybe it might not be so easy to access it though. In that case, couldn't you run a new piece of pipe in some other direction and connect to that instead? If that galvanized goes through the roof, just cut it off someplace in the attic where you can reach it, where it isn't blocked by joists and other wood, and then fix the hole in the roof.

Edit: one other thought - was the pipe which "snapped off" actually threaded into that elbow? Since this is just a stack maybe somebody just shoved the smooth ends together and sealed it somehow? So when you cut off the bottom, it just fell out, because it was supported only from the bottom.

 

[hopkinmn]

What snapped here, the pipe screwed into that elbow or the elbow itself? From the picture that elbow (or the remainder of the broken pipe) looks like it is in very good shape, with just a little rust on the inside and plenty of metal.

Is part of the old pipe still stuck in there? Are the threads of the elbow OK?

Anyway, it seems to me that if there is substantial bit of the snapped pipe still in there you should be able to screw it out, probably after soaking it for a while with penetrating oil. If it is just the threads which are messed up, then you could retap it.

Or as breplum suggests, just replace that piece of galvanized entirely. I can see where maybe it might not be so easy to access it though. In that case, couldn't you run a new piece of pipe in some other direction and connect to that instead? If that galvanized goes through the roof, just cut it off someplace in the attic where you can reach it, where it isn't blocked by joists and other wood, and then fix the hole in the roof.

Edit: one other thought - was the pipe which "snapped off" actually threaded into that elbow? Since this is just a stack maybe somebody just shoved the smooth ends together and sealed it somehow? So when you cut off the bottom, it just fell out, because it was supported only from the bottom.

The pipe stack in is the piece that snapped. The threads of the elbow are fully gunked up, so it would need to be retapped to use again.

That is a good question though, if maybe it was sealed some other way. It doesn't appear to have any other type of sealant on it, and the threads of the stack are pretty rusted away.

Hard to explain clearly, but the vent is in a spot where replacing it would be quite tricky. It heads toward a short section of floor that is cantilevered over the foundation, and then it heads up through the cantilevered exterior wall to the roof. I'm considering running a new vent line elsewhere, but am not sure if it would be any easier than replacing the old one and using the same space.

 

[hopkinmn]

Hello,

Follow this link, it may fit your situation.

https://www.supplyhouse.com/Fernco-...t-ABS-Coupling-for-Sewer-Pipe-DWV-Connections
Internal diameter should match. Not sure how it would fit inside the fitting, especially that it is a 90.

Only other option would be to cut the pipe and connect along the run between the joists.

I hope it helps.

The internal diameter of the elbow is just less than 1.5", and looks like these come in only 4" and 6" diameters. Seems like it would be just the thing if it were smaller.

 

[hopkinmn]

Picked up one of these puppies at Lowes today: https://www.lowes.com/pd/Fernco-2-i...MCVbIZgXoPDMDK3sShxoCSb4QAvD_BwE&gclsrc=aw.ds

Measuring the inner diameter of the fernco, it just might fit over the elbow. Would there be a reason I shouldn't go this route?

 

[Daulton Ruff]

Old galv. Pipe is 100% worth getting rid of.
Aside from a pipe tap, you are sunk…

I have 1970 era galvanized pipe throughout my ranch style house. I've thought about removing and putting in plastic modern pipe because I think there is a lot of corrosion in them. I'm just worried about the cost. Access would be fairly easy because of a raised foundation.

 

[pasadena_commut]

The pipe stack in is the piece that snapped. The threads of the elbow are fully gunked up, so it would need to be retapped to use again.

"Gunked up" how? If the pipe snapped there should be a chunk of pipe still in the elbow. Unless you already removed it. You should be able to obtain the appropriate tap for $20-$40 or so. If it was me I would try that first. (Well, I am a little biased, because I already own such a tap, so that approach would now be "free".)

 

[themavinator]

What snapped here, the pipe screwed into that elbow or the elbow itself? From the picture that elbow (or the remainder of the broken pipe) looks like it is in very good shape, with just a little rust on the inside and plenty of metal.

Is part of the old pipe still stuck in there? Are the threads of the elbow OK?

Anyway, it seems to me that if there is substantial bit of the snapped pipe still in there you should be able to screw it out, probably after soaking it for a while with penetrating oil. If it is just the threads which are messed up, then you could retap it.

Or as breplum suggests, just replace that piece of galvanized entirely. I can see where maybe it might not be so easy to access it though. In that case, couldn't you run a new piece of pipe in some other direction and connect to that instead? If that galvanized goes through the roof, just cut it off someplace in the attic where you can reach it, where it isn't blocked by joists and other wood, and then fix the hole in the roof.

Edit: one other thought - was the pipe which "snapped off" actually threaded into that elbow? Since this is just a stack maybe somebody just shoved the smooth ends together and sealed it somehow Sheet Piles in UAE? So when you cut off the bottom, it just fell out, because it was supported only from the bottom.

1. Can I run PVC conduit underground for the buried section, and extend both ends
above ground using rigid steel conduit?

2. Is it a good idea?

3. I have heard of the exception in the NEC permitting elbows to be steel in an otherwise non-metallic conduit run to avoid abrasion when pulling wire.

PVC can and does fail in heat and exposure. Hence the Q.