Seized nut on copper trap/waste outlet problem.

Can you cut through the copper trap? Hacksaw?

Ian, thank you for your interest.

I am not sure I understand your meaning. I am wondering where you would cut the shallow copper trap? If the copper trap was cut off close to the retaining nut, the nut would still be in place on the waste outlet tail, together with some remnants of the copper trap. I don't see how a new trap could be fitted in such circumstances. It looks as though I have not caught up with your thinking?

Were you thinking that the trap could be cut, leaving a tail in place, onto which a compression fitting could be fitted? Unfortunately, because it is a shallow trap, there does not seem to be enough copper there to do this.

Cycle.

to release it you need to cut through the nut, hacksaw, dremel or drilling would be my preferred options

mrcheerful - is cutting through the nut in one position likely to release the gunge of 30 years to enable the nut to turn? I have no experience in this area, and was wondering what to expect.

If I had a go at this, presumably I would have to first cut off the copper trap, close to the nut. This would then give access to cut along the retaining lip of the nut (i.e. along a diameter), before making another cut at right angles, this time along the thickness of the nut.

Personally, I'd drill through the side of the nut then open it up with some form of wedge.

Go to

I'd guess that the waste is steel or brass, and the copper has well and truly 'welded' itself to it through chemical action. I've had exactly the same on a central heating pump.

You'll have to cut through the copper nut with a saw. Perhaps something like a dremel if space is tight. There's no point in trying to save it as the threads will likely have eroded away anyway.

Thank you for the suggestion of using a nut-splitter. I note that the maximum size of the Screwfix item is 22mm, whereas the nut I am dealing with is around 45mm. I bought one of the Screwfix sets a couple of years ago, and tried using the small size splitter. The nut was undamaged, but the splitter wedge-end started to flake apart. Perhaps they are of better quality now.

Have you any experience of how likely it is that cutting through the captive nut will allow it to be released from 35 years of being "welded" by chemical action? The tail of the waste fitting will need to remain intact if It is to be reused to make a watertight join onto a new trap. I believe (from what I have read) that the thread on the captive nut of a new trap is still the same size as it was in 1968 when this fitting was new. So a new captive nut will fit on the 1968 waste fitting tail.

That was a useless suggestion then. A big nut is an easier target for an angle grinder :-)

I was there looking for something else - I've never tried that particular type.

Once you've cut - or nearly cut - through, a twist of a screwdriver in the slot should split it and spring it free. You won't need much force.

Yup - I don't think those threads have ever changed.

The big snag with these things and plumbing is that you have to slip it over the pipe. ;-)

Thank you for the information. I think I shall arm myself with a Dremel, plus two sizes of hacksaw as a backup, and see what happens.

Regards,

Cycle

Easy enough to chop a bit out then join it again afterwards - well, easier than shifting a seized fitting in an awkward corner anyway. But I'm more of a mechanic than a plumber - can you tell? :-)

Oh I've got a set and use them on car stuff - but often you still can't get them on. Common nuts to seize on a car are exhaust ones - and there's not usually enough clearance between the pipe or manifold and nut for a splitter.

It's not that common for plumbing type joints to seize solid, since the majority are brass to brass. But brass or copper to steel seems to be a problem.

But that's a brass nut on a steel bolt - a quick blast with the oxy- acetylene will have it dripping off in no time :-)

If only they were. Can you see the likes of Kwik-Fit using brass nuts? ;-)

A drill could well be quicker. Use it to drill a hole part way through the nut and then give the nut a tap with a sharp tipped tool. It should open the nut a treat.

Dave

If its as difficult as it sounds, it might be a lot easier to just line the inside of the trap with a long lasting setting gloop.

NT