Today, I tried to replace the tap unit to my mom's hose because the 40-year old tap was leaking water everytime I turned the water partially on. So I used a vise grip to try to unscrew the tap. The nice news is the tap is removed, but the bad news is it was not removed completely. In fact, part of the threading is still stuck in the barrel. Now remember, no plumbing work was done on this in like 40 years at least.

I tried various methods to remove the threading inside. First I tried scraping a kitchen knife around in hopes it eats at the metal. it only removed tiny pieces.

I then tried an interior wrench tool which looks like a stick that you put inside and turn with a wrench. That was also unsuccessful.

I even tried 60 grit sandpaper. That also does not work.

Now, my mom suspects the metal on the old hose tap is brass, but I think it is copper. I measured a new tap with a conductivity meter and surely enough it conducts electricity. Makes me think maybe it is copper but then again could brass conduct electricity?

Anyways, the only other thing I would consider trying is some sort of chemical to eat the metal. The only thing I have on hand is ferric chloride liquid that removes copper, but isn't there a better chemical or method I can use to get the stuck metal piece out?

I also suggested to her that a torch might be in order to help remove the part because I'm guessing some sort of chemical adhesive was used to keep the tap from leaking in the wrong places. but is there another way to do it without having to resort to using a torch?


This is the front view of the hole. I added red arrows to give you an idea of how far in I need to go to remove the stuck part.


This is the side view of the whole unit.

Side hole

  • 2
    All metals conduct electricity. Leave the ferric chloride for etching circuit boards, it will likely hurt more than help here. An actual photograph would be more useful than the diagram in assessing the problem. Heat might help because it can help to release the corrosion that has probably occurred between the coupling (likely galvanized iron, but a picture would help) and the brass faucet (copper would be highly unlikely for a machined part like that.) In some cases you may have to remove the pipe going inside the house (to find a connection that is removable, intact.)
    – Ecnerwal
    Commented Jun 2, 2020 at 23:00
  • Can you access the pipe inside the house? Alternatively, cut the pipe inside, pull out the assemby, Create new exterior hose bib assembly with length of pipe, and reconnect pipe inside.
    – DaveM
    Commented Jun 3, 2020 at 16:42

3 Answers 3


With the new photos added we can see you're working with a regular 1/2 inch coupler on the end of a piece of pipe. Both are probably "black" iron pipe (as opposed to being galvanized pipe).

I suggest removing and replacing the coupler. That'll probably be easier than cleaning out the internal threads. You'll need a pair of pipe wrenches, and heating the coupler with a torch could help too.

For reassembly, apply a pipe thread sealant on the outer/male threads. The white teflon tape is a common choice but my personal preference is usually a paste compound (often generically called "pipe dope"). Being wet it's a bit messier than the teflon tape but in my opinion it lubricates better for assembly and it seals better too.

  • A good vice grip should hold the pipe if there is not enough room for a pipe wench. Commented Jun 3, 2020 at 21:13
  • I actually tried that once with the vice grip and the seal was so strong I couldn't even turn the thing. Is there any way I can get by this without using a torch? Commented Jun 4, 2020 at 17:11
  • If you can't get a pipe wrench between the wall and fitting, you'll need 2 people. One person in the basement/crawl space to hold the pipe with a pipe wrench, and one person outside to unscrew the fitting. TBH, as rusty as that piece of pipe looks behind the fitting, you may want to seriously consider replacing it, too. Running an fresh piece of galvanized pipe from somewhere under the house, through the hole and out. Put the proper fittings on each end and call it good.
    – FreeMan
    Commented Jun 4, 2020 at 17:31
  • You wouldn't have to use a torch.. I never have. The heat would make the coupler expand, loosening the fit and possibly also breaking some of the corrosion bond. Brute force alone can get the job done too though. Mostly I work with 14 inch pipe wrenches but there have been a couple occasions when I've used a cheater pipe to make the handle leverage 6-10 inches longer. Yours might be the kind of job where I'd end up doing that.
    – Greg Hill
    Commented Jun 4, 2020 at 19:15

A photo of the pipe would be helpful, copper pipe is a possibility but the faucet will be almost certainly brass, I agree with Ecnerwal leave the ferric chloride for pcb’s it would take forever with that thick of a material.

I would use heat plumbers dope commonly used to seal threads works great but turns rock hard after a few years , I have found heat the only way to remove in the past, if this is a copper pipe to a brass fitting that is sweated heat will be the only way to remove it unless you cut it then use a shark bite to repair the stub , again I prefer heat, but a photo of the part may provide us the information to give exact instructions.


Old fixtures are likely bronze ( copper , tin ,+ maybe Zn and Pb), very unlikely copper. I have reached into the bore with a hacksaw blade ;you may need to grind down the back of the blade to fit into the bore. Try not to damage the female threads . I have done it a few times with steel, bronze should be easy. You will probably need to make two cuts, then take a screwdriver and pry the cut halves away from the female threads. A recip saw is much faster but much higher risk of damaging female threads. Holding the hacksaw blade with vicegrips works well.

  • I was thinking about using a saw. I did measure the whole thing inside including the problemmatic part and I determined that when everything is done, I can fit a standard faucet with a 1/2 inch connector into the hole. I added pictures to my question. Commented Jun 3, 2020 at 18:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.