View Full Version : Loosening stubborn fittings

John Terefenko
02-24-2018, 11:27 PM
Is there any product out there that can help in loosening stubborn fittings. I have a steel drain pipe that has a copper fitting screwed into it and the nipple has corroded and It is too tight to wall to resolder so I would like to take the copper fitting out of the steel sewer line and replace with plastic and replumb. The 2 dissimilar metals probably has corroded and it is making it tough to turn out. I have tried liquid wrench and heat but no movement and Have a wrench on it with a lever. Any suggestions???

Jim Koepke
02-25-2018, 2:05 AM
The last time something like this happened to me the piece inside the joint had to be cut and then curled around some long nose pliers to get it out. Then an end of a male threaded pipe had a little more than half the threaded portion removed to make a thread chaser to clean out the old threads.


Charlie Velasquez
02-25-2018, 8:38 AM
It is DWV so there is no pressure on the fitting. A sawzall or similar and these in the appropriate size
are your friend. Quick and painless.

(edit: steel drain? Unusual, but no matter, also works with copper, cast iron, pvc, chrome...)

George Bokros
02-25-2018, 8:49 AM
If you must get it out try PB Blaster. It has worked better than other penetrating products for me. Available at most auto parts stores and not sure about Lowes/Home Depot.

John Olier
02-25-2018, 10:22 AM
Try tapping the steel pipe with a hammer. Sometimes the jarring action of the blows will free the threads enough to allow movement

Ken Combs
02-25-2018, 2:13 PM
Try tapping the steel pipe with a hammer. Sometimes the jarring action of the blows will free the threads enough to allow movement

Good suggestion. It helps to use two hammers if it's accessible. Place a hammer heavier than the one you will use to hit it against the side opposite where you will be hitting. I use a 12-16oz to hit and a 2 or 3 lb engineers hammer to back it up. That allows you to hit harder without bending or breaking the pipe. It will also cause the opening to flex to an oval when hit. Try smacking it from at least two places 90deg apart.

Lee Schierer
02-25-2018, 2:48 PM
As you've figured out joining copper pipe to steel or iron pipe is bad news. It is likely you will need to replace the copper fitting as it is probably badly deteriorated. JOints of that type should have an insulator bushing between dissimilar metals.

Rich Engelhardt
02-26-2018, 7:28 AM
I'm snake-bit when it comes to anything at all where plumbing is concerned.

I just pick up the phone, call the plumber and pay the bill.

My luck would be that the old galvanized steel would snap off inside the wall - or worse - and be a huge problem instead of a small one.

John K Jordan
02-26-2018, 11:05 AM
I'm snake-bit when it comes to anything at all where plumbing is concerned.

Ha! I don't like plumbing and don't like anyone who likes it. (just kidding! :)) I really like HAVING plumbing though. The inside plumbing is especially handy.

I've done a great deal but these days I also call the plumber especially for something tricky. I've had too many experiences with having to tear into walls and break into block concrete, even a couple of weeks ago. Shark bite fittings are my friends. Pex is my future friend.

I didn't see a photo or good description from the OP but if the steel pipe is embedded in the concrete it may well be sturdy enough to work aggressively on the copper piece without damaging anything else. I also reach first for PB Blaster and tapping/vibration to loosen things but heat also helps a lot on occasion. Depending on the level of corrosion cutting it out might be the best solution, or just cutting the steel pipe.

As for soldering close to the wall that might still be possible if there is room for inserting something to shield the wall from the torch. Also, most soldering on plumbing can be done from one side with the flame directed somewhat away from the wall. This would depend, of course, on the actual installation and clearances.


Malcolm Schweizer
02-26-2018, 11:14 AM
Not sure how well this would work on plumbing, but it worked on a stuck nut on the Jeep. It seems counter- intuitive, as cooling would tighten, not loosen, but I believe it’s the instant contraction followed by returning to normal temp that helps loosen stuff.

michael langman
02-26-2018, 11:41 AM
I watched a plumber use a circular torch head that completely surrounded the pipe and flame was directed on only the pipe.
It helps to have the right tools for the job sometimes.
Sometimes it takes a lot of torque to brake pipe fittings free. With a pipe wrench on the steel pipe and a pipe wrench on the copper pipe put everything you have into turning the copper pipe out. A map torch might get the copper hot enough to brake it free.
The steel pipe is acting as a heat sink and not allowing the copper to get hot enough to help. An acetylene torch would probably help if the map torch does not.

John Terefenko
02-26-2018, 5:57 PM
Just an update BP blaster worked. I sprayed over night and today took a chain wrench and lever and it spun off very easily. I was surprised to say the least. That stuff does work. This is all getting changed to plastic. The heck with all this disimilar metals. I got steel, copper, and now brass at the tube and all is corroded to the point I take one joint apart the next one falls apart. The steel drain is still solid so not changing that now and the kitchen sink drains into it also and it is working fine. If down the road I need to change that section of drain piping it would an easier job now that I can clean up this bath tub stuff. thanks everyone.

George Bokros
02-26-2018, 6:20 PM
Glad that worked for you John. That stuff is amazing. The maintenance supervisor at a place I previously worked put me on to it. I used it last summer to remove the clamps and bolts from some auto exhaust fitting on one of my muscle cars and I got them all off without twisting them off, first time ever.

John K Jordan
02-26-2018, 7:31 PM
[PB Blaster] is amazing. ....

I agree. I bought a gallon last time. Sometimes I pour enough in a container to soak parts and things like rusty locks then save for reuse. The gallon I bought came with a plastic spray bottle to refill.

John Terefenko
02-26-2018, 10:38 PM
That stuff made a believer out of me. So glad I asked here. Saved me extra work trying to cut and chisel that thing out. Threads are nice and clean and plastic screwed in nicely. That goes in the tool box. Thanks.