[tatgeer]

I'm trying to replace the J-joint in my basement laundry room sink, and the nut on the old piece broke - part of it is still on the pipe going to the sink. I've tried spraying it with WD40, but it won't budge. A friend suggested heating it. Any other ideas?

[labman]

Few nuts can resist heating with a torch and quenching. On the other hand, neither can rubber or plastic parts. Wood often catches fire. Perhaps a hammer is safer. Wet the area with WD-40. It is as good as anything for getting things loose. Then tap around the nut. If you can get a punch on the end where it will tend to turn the nut loose, that should be very effective. Once the nut starts to turn, finish with a wrench if there is enough left of it. When you put things back together, clean up any threads you are reusing good with a wire brush.

It is better to use the hammer or torch before you break something.

[tommytman]

Take a cold chisel and hammer and smack-it. Or take a saw and cut off the parts of the pipe you don't want anymore then try to cut sections of the nut and knock them off with a hammer.

Or just try cutting the nut in different locations then hitting it or prying it. A small hacksaw or dremel tool would work.

[speedball1]

I'm trying to replace the J-joint in my basement laundry room sink, and the nut on the old piece broke - part of it is still on the pipe going to the sink. I've tried spraying it with WD40, but it won't budge. A friend suggested heating it. Any other ideas?

You describe a nut that's hung up on a tailpiece connected to the sink drain.
If this were my call I would disconnect the tailpiece and the stubborn nut and toss them. I would then purchase a new tailpiece, nut and washer and reassemble the trap. Cheers, Tom