I suspect that proper plumbers probably wouldn’t give it houseroom, but it’s a godsend to do-it-yourself amateurs.
If a water leak’s becoming quite a problem in your plumbing
And mending it’s a job you really hate,
Don’t despair, for here’s my point: you can seal that pesky joint
With a generous blob of good old Plumber’s mait.
It’s really quite fantastic, this tub of off-white mastic,
And helps us DIYers extricate
Themselves from tricky spots just by using lots and lots
Of Evo-stick’s amazing Plumber’s mait!
(‘Plumber’s mait’ is Bostik Limited’s registered trade mark UK00000827265.)