Since one of the most common methods of finishing a large number of paint materials at present is the spray-off method, when testing these paint materials, it is necessary to determine their "spray performance", as well as the paint film obtained by spraying the paint on the surface with a paint sprayer. quality measure.
The test is carried out with a special Spray Gun-type atomizer. When spraying with a paint sprayer, the varnish or paint sprayed with very fine particles can be sprayed into a uniform layer on the surface. The spraying of paint materials is done by compressing to 2~ 3 atmospheres of air, only varnishes and paints with a certain viscosity are suitable for spraying.
The spray-off performance of varnishes or paints is determined by spraying the material to be tested on a wood or steel surface that has been previously treated in accordance with the requirements for that paint, e.g. when testing oil-based varnishes and enamels, the surface may be Treatment as described; primer removal and putty are also required when testing nitrovarnishes and enamels on metal surfaces, in which case the oil-based resin primer and putty must be applied before nitrovarnish is applied. Dry at 100~110℃. (Related instrument: drying time Tester)
Spraying should be carried out in a special, well-ventilated coating room, and write down all the phenomena that occur when spraying the varnish and base paint to be tested: such as the formation of sagging, darkening or whitening of the paint film, etc. In good quantities, paint materials suitable for spraying with a paint sprayer shall be capable of forming a uniform and completely smooth glossy paint film. In special cases the paint film can also be matt. (Related instruments: Sag Tester)
Today's known paint sprayers are very diverse in construction.
There are many types of KP paint sprayers produced in the Soviet Union. It has various equipment for conveying paint and Spray Guns of different shapes. KP-10 and KP30 Spray Guns are most suitable for laboratory work. KP-10 Spray Guns (Figure 86 ) paint is indeed arranged on the upper part of the gun body, and the paint flows down from the center automatically. The KP-30 type as (Fig. 87) paint pot is installed in the bottom of the gun body, and the paint is sucked up, and there are holes for the air to compress the paint flow on the nozzle sides of the two kinds of Spray Guns, which can be used The hole is used to adjust the paint from a cylindrical shape to a horse-shaped paint shape. When spraying with a paint gun or a paint gun, when the pressure is 4 atmospheres, an Air Compressor operating at about 15 m a/h is used as the source of compressed air. , The policy is to use the air in the compressed air pipeline with normal pressure. The compressed air needs to be clean, so the air must pass through the oil-water Detector in advance. The structure of the spray paint inspection is shown in Figure 88.
