Apparatus for spraying liquids, and adapters and liquid reservoirs suitable for use therewith

Apparatus and methods for spraying a liquid relating to a gravity-fed spray gun are disclosed. Disclosed gravity fed spray guns may comprise a body and an attachment point located at a top portion of the body; and a spray nozzle located at a front portion of the body. An apparatus may further comprise a fluid reservoir configured to contain a fluid to be sprayed through the spray nozzle, the fluid reservoir comprising a container comprising an open end; a lid for cooperative engagement with the open end of the container, the lid comprising a connector to couple the fluid reservoir to the attachment point of the spray gun and an aperture through which the fluid can flow from the fluid reservoir to the spray nozzle in use; and a filter positioned to filter the fluid before reaching the spray nozzle.