1 mug flour, 2 mugs water. Heat to steaming, keep stirring until it’s all thickened
Take off the heat and beat any lumps out, add ~half cup cold water and stir in to achieve a pourable consistency
Pour into a large protein shake cup (~700ml?) to store and use. Store in the fridge, use by pouring directly onto the pasting brush.
Should be enough to paste up about 40 A4 posters