Separating rusted Galvanized Steel Union?


  #1  
Old 12-12-16, 10:19 AM
J
Member
Thread Starter
Join Date: Sep 2016
Location: USA
Posts: 21
Upvotes: 0
Received 0 Upvotes on 0 Posts
Separating rusted Galvanized Steel Union?

I have a long length of 3/4" galvanized pipe which has been buried for a few decades. As you might expect, it has a light layer of rust on the outside.

I want to separate and remove a union WITHOUT messing up the pipe's threads, so I can thread either a new union or coupling on that pipe. My plan is to use a lot of PBlaster on the connection and let it soak for 24 hours, then repeat, then use two big assed pipe wrenches on it.

Anyone know of a better technique for removing the union while leaving the threads usable? I used conventional gray pipe joint compound on the fitting 30 years ago; no Teflon tape or modern white Rectoseal compound.
 
  #2  
Old 12-12-16, 10:42 AM
C
Member
Join Date: May 2015
Location: USA
Posts: 3,105
Received 144 Upvotes on 117 Posts
Heating the fitting (not the pipe) may help as well. But I would have a plan B in mind in case the pipe has rusted from the inside and just crumbles when you try to remove the union.
 
  #3  
Old 12-13-16, 07:37 AM
J
Member
Join Date: Jan 2011
Location: USA
Posts: 4,463
Received 128 Upvotes on 113 Posts
If it was mine I'd be spending my time digging it all up and replacing with some form of plastic pipe.
Steel pipe will rust out from the inside out 100% or the time even under the best of conditions like inside a home.
You'll have rusting issues on the inside and the outside.
First thing I do when buying a home that has steel plumbing is figure out what it's going to cost to replace it and take that amount off the asking price.
 
  #4  
Old 12-13-16, 04:27 PM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,494
Received 800 Upvotes on 703 Posts
I agree with Joe, it would be better to tear out the galvanized and replace with PVC.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: