In order to prevent the impurities from getting on the objects to be coated or clogging the nozzles, filters and sieves of the correct mesh size are very important. Filters are often used in combination. Intake filter, device filter, gun filter and nozzle filter. The most important thing about choosing the right filter is that the mesh size of the last filter in front of the nozzle is finer than the nozzle bore. Upstream filters should always be a bit coarser than the following.