Can't unjoin iron pipe

I've always heard that approach. I've never in my life been able to unstick a ferrous pipe union, other than by breaking it. Good luck !

Go buy or rent two three foot pipe wrenches and put some umph into it.

-- Tom Horne

"Were not making watches here kid! Never use force, get a bigger hammer!" Henry T. Horne III, Master Plumber and also my father. May God rest his weary soul.

toller posted for all of us... I don't top post - see either inline or at bottom.

Hey tollar do you EVER use Google? Huh? Just once give it a go! OK!

Try melting beeswax into the threads.

penetrating

Which most likely will result in a collapsed or twisted pipe (BTDT).

Harry K

That has not been my experience on literally hundreds of stubborn galvanized iron joints. If the force is applied gradually the joint will break free without damage.

-- Tom Horne

I just had to remove a 1 1/2" galv steel drain stub.

My usual trick did not work:

Very large pipe wrench used to TIGHTEN the joint ~ 1/8 or less; just enough to budge it. Then loosen it.

In this case I had to use a Sawzall to slit the pipe & collapse enough to relieve the thread pressure.

Liquid wrench is good.

Bob

(BTDT).

You obviously had the pleasure of never following behind my father. His method of tightening pipe was 'as tight as it will go plus 1/2 turn'.

Harry K

One of my father's tricks for breaking loose a rusty fitting was to beat on it with a hammer until it broke the grip of the rust.

Or it simply broke... :)

There are a lot of "threads" that appear here that could use some "penetrating" oil.

I'll have to give you that one Harry. Another of my dads slogans was tighten with an eighteen, loosen with a thirty six.

-- Tom Horne

That's more nearly describing heat, not impact (the expansion part, anyway)... :)

You appear to have missed the smiley on first go. Although it helps on occasion, I've not had universal success with the technique on, for example, buried supply lines.