• Schematic: Thorium Grenade
• Item Level 52Disenchants into:
  Not disenchantable
• Requires Engineering (260)
• Use: Teaches you how to make a Thorium Grenade.
• [Thorium Grenade]
• Requires Thorium Widget (1), Thorium Bar (3), Dense Blasting Powder (3), Runecloth (3)
• 1 Charges
• Sell Price: 30

Source

This recipe is now taught by Engineering trainers.

Until patch 2.2 (estimated), this was a limited sale recipe sold by

•  Gearcutter Cogspinner in Ironforge
•  Sovik in Orgrimmar.

External links

• Battle.net (EU)
• Wowhead
• Thottbot
• WoWDB