Peristaltic pump There are a few plaster sprayers that have a peristaltic pump (a tube squeezed by rollers) which also requires compressed air to produce a spray. These types of plaster sprayer can also spray textured coatings with particle sizes up to about 3mm diameter, providing that they are not solvent based.
Piston pump Newer types of plaster sprayer have a piston pump, which has sufficient pressure to spray smooth (untextured) plaster without compressed air. Full airless pumps are sometimes used to spray smooth plaster, although they are not ideal as the flow rate is too low for volume projects; however, they can be used to spray solvent-based plasters.
Air operated piston type supply pumps can put out as much as 27 gpm. Like the Graco Bulldog 10:1 at about 9 gpm and the Lincoln Pile driver 5:1 at about 27 gpm. These flow-rates are calculated at a maximum of 120 cfm air supply. Material supply hoses are medium pressure at about 600 psi. These pumps are material supply pumps only and additional air is required at the Spray Gun to propel the material to the surface. These guns are usually an internal mixture type guns where the material and air exits the gun together.
