How To Hang A Slate Sign . Signs made from slate that hang from a bracket are very common and popular for a wide range of properties and businesses. Prep the wall and clean the surface where the sign will be installed to remove oils from handprints that can hinder adhesion. Personalised Hanging Slate Sign Any Message GettingPersonal.co.uk from www.gettingpersonal.co.uk Measures 25 x 10 x 0.8 cm. It's not a shed it's a f**king bar slate sign plaque pre drilled with cord ready to hang great gift birthday xmas laser engraved bar sign $13.11. Take the slate to a well ventilated area (preferably outside) lay it on a protected surface and get your mask back on.