Systems for material deposition. One such system includes a number of containers arranged relative to one another in a conical or other shape, pointing toward a common deposition point. When not actively depositing material, the containers are held at a distance from the deposition point. Another system has a rod disposed within a container and a flexible tip on the rod seals a material exit of the container when biased closed. Pressurized gas introduced into the container forces the rod away from the material exit and material from the container. In yet another system, a container includes a barrel adapter having a one-way air valve that seals the container and creates a vacuum, preventing material from leaking from the container. Upon application of a pressurized gas, the one-way valve is forced open and material is deposited from the container. The valve closes automatically in the absence of the gas.