A sash and trim brush normally comes with a thin and long handle to aid in maneuvering. A small, square-edged or flat sash brush works best for painting thin objects such as the thin pieces of wood that separate individual panes of glass in doors or windows. Straight sash brushes vary in width from 1 inch to 3 inch with 1-1/2 and 2 inch being the most popular. Professionals may opt for larger sizes. Straight flat sash brushes come with a slim long handle such as a rat-tail or pencil handle.
Synthetic Paint Brushes can be made of a vast quantity of different materials. Different synthetic filaments have different characteristics and therefore produce a different brush, suited to different types of paint and different temperatures of the surface.
Nylon is a very durable filament that resists wear on rough surfaces. Nylon filaments last much longer than pure bristle and considerably longer than polyester. Nylon tips precisely for a smooth professional finish. Nylon cleans completely and easily. Nylon softens in hot weather and with prolonged use with latex paints. Nylon was developed with latex paint in mind, but is often blended with other filaments to enhance a brushes properties. For the professional, there are some advanced nylon filaments that maintain stiffness better as well.
DuPont Chinex® ;asts 7 times longer than bristle. It maintains its stiffness for control, even at higher temperatures and increased humidity. It was developed because with Today's Low VOC coatings, it's stiffness became a necessity. It is properly tapered, narrows down as it gets longer, tips well and offers the perfect balance of paint pickup and release. Chinex cleans completely and easily.
Polyester can vary greatly in quality and durability. While some can be chemically tipped, others do not tip well. Some are tapered, others are straight and some are hollow. Very thin polyester filaments virtually eliminate brush marks, but do not carry or release a lot of paint, therefore take more time to get the job done. Polyester is more difficult to clean and takes some time. This results in lower production. How To Choose The Right Paint Brush For The Job