Any tricks for getting old pipes apart?


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Old 05-20-12, 08:35 AM
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Question Any tricks for getting old pipes apart?

Does anybody know of any good tricks to make it easier to get pipe joints apart when they've been sealed with thread sealant and left to harden for 20-30 years? These are mostly 2"black pipe with malleable iron fittings, and I'd like to be able to re-use most of the nipples and fittings if at all possible.

Here are a couple of things I know won't work:
  1. penetrating oils (e.g. WD-40): It's great for rust, but it can't penetrate sealed threads.
  2. breaking fittings with a hammer: No way. They're malleable. Besides, I want to re-use them.

I haven't tried any solvents, but thread sealants are pretty resistant to chemicals, especially once they've set.

Heating the fittings seems to help a little, I think, if I can heat the fitting quickly without also heating the pipe, but on 2" that's hard to do.

One thing I've found that really works is impact, but other than a few plugs and bushings where I have a socket that fits, this isn't really relevant. Someone could make a lot of money by inventing an air-impact pipe wrench.
 
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Old 05-20-12, 09:15 AM
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What size wrenches are you using?
 
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Old 05-20-12, 10:45 AM
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A 36" and a 48" pipe wrench.
 
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Old 05-20-12, 11:10 AM
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Working alone or with a partner?

Try using PB Blaster. WD-40 doesn't seem to do much. I pulled apart some threaded pipe that was together for 80 years. Not quite 2" though. I don't know if the threads needed it, but I did squirt PB Blaster on them prior to using the wrench. One came apart fairly easy, the other took a lot of braun, but I go tit loose. There was no thread sealant on the threads either. I think the problem you have is that the fittings are tapered and designed to seal metal to metal with thread sealant. With a 2" pipe, that takes a lot of forced to get them properly mated. So you need to apply more than the priginal torque to get the apart.
 
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Old 05-20-12, 12:06 PM
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I agree with droo. PB Blaster works really well. WD-40 is just a water displacement product (hence WD). It does not lubricate and does not penetrate. It displaces water. For long term lubrication, and quick release agents, use PB Blaster. They have a full line of products.
 
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Old 05-20-12, 02:53 PM
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Guys, nothing is going to penetrate those threads. Whoever put them together was very generous with the thread sealant. I've been wire brushing it off of the threads of the pipes I've gotten apart.
 
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Old 05-20-12, 04:01 PM
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The old pipes

Try rapping the fittings with a small to medium hammer. This will slightly expand the fittings , just enough to loosen them and to be able to get them off. Try to rap them most of the way around if possible. This principle is much the same as when you or your wife rolls a jar top on the kitchen counter to lossen it. As the fittings are mallable, they won't be damaged by this procedure. Maybe use eye protection.
Sid
 
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Old 05-21-12, 02:35 AM
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Thanks, sidny. That does seem to help. It might even help break up the sealant, and if it does, that would allow some penetrating oil to get in there.
 
 

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