This quest is not available in game.
Obtain 20 vials of Spellsludge.
Spellsludge can be found on the powerful Underbelly creatures that appear while the Dalaran Sewer Guards are on duty.
For my next project - sticking the forge's components to one another - I need a magical adherent. And I've found that the built-up sludge of Dalaran's sewers works perfectly for just that.
It cakes up on the feet, boots, and slithering bellies of Dalaran's more long-lived residents. Scrape some off and bring it here.