On 03/04/2012 21:26, Chris Holford wrote:
In , Fredfred@no-
email.here.invalid writes
On Sun, 1 Apr 2012 09:34:05 +0100, Chris Holford
wrote:

I've tried a plunger, and tried
neutralising with spirits of salts

Still waiting for the NaOH to dissolve!

Does water drain away at all? If so your only remaining option is to
risk adding very hot water and hope that it will solvate the caustic.
Repeat hourly until the thing runs free again.

Wear eye protection and if possible a full face shield.

Otherwise you are down to a dismantling job. Next time make up the
solution carefully from the solid and pour it down the plug hole!
(again eye protection essential it gets pretty hot when dissolving)

I reckon most people are better off with one of the proprietory drain
cleaners since it avoids pitfalls like this one with overdose of the
solid causing a worse problem than the fault it was trying to fix.

--
Regards,
Martin Brown