Abstract: A liquid container containing liquid, such as paint, to be applied to a surface includes a radially inwardly facing sealing wall on the top of the container extending in a complete circle around the center of the container. An aperture is provided in the top of the container inside the sealing wall. The sealing wall has a depth of at least 4 mm and there is a free space projecting at least 4 mm radially inwardly of the sealing wall and extending in a complete circle around the inside of the sealing wall. In use the container is housed in an outer vessel, a conduit passes through the outer vessel and the top of the container to the bottom of the container, and a pressurizing assembly is provided for applying pressure inside the container. The outer vessel includes a circular seal member mounted on a radially outwardly facing wall extending downwardly from the top of the vessel and cooperating with the sealing wall on the liquid container.