The subject matter discloses a painting apparatus comprising a paint bag containing paint; a paint port through which paint flows from the paint bag; an air bag to receive gas configured to apply pressure to the paint bag as it receives air; an air port through which the gas enters the air bag; wherein the air bag and the paint bag are located within the painting apparatus, such that expansion of the air bag by pumping of the gas into the air bag forces the paint from the paint bag via the paint port.