The best brushes have a generous filling of long bristles and are an even, tapered shape.
Cheaper brushes have short, thin bristles and big wooden filler strips to pack them out.
The ideal sizes for wood are:
• 25mm (1 in) or 50mm (2in) for panel doors, skirtings
• 50mm (2in) or 75mm (3in) for flush doors, skirting, large areas
• 25mm (1 in) cutting-in brush for window glazing bars
• 12mm (Vfein), 25mm (1 in) or cheap paintbox brush for spot priming, applying knotting
Alternative to brushes
Paint pads are more widely used on walls than on woodwork, but the crevice or sash paint pad will do the same job as a cuttingin brush. It should be cleaned with white spirit or hot water and washing-up liquid (paint solvents might dissolve the adhesive between the mohair pile and foam).
TIP: PREPARING A BRUSH
Before using a new (or stored) brush work the bristles against the palm of your hand to remove dust and loose hairs.