The Army Painter Colour Primer Gun Metal, 400 mL Acrylic Spray Primer, Spray Paint Basecoat for Miniature Priming, Tabletop Roleplaying, Boardgames, and Wargames Miniature Modelling : Amazon.co.uk: DIY & Tools
Humbrol Acrylic Grey Primer - how to spray - Scale Modelling Now
Humbrol: How To Use Acrylic Spray Primer - YouTube