Coating Application
POWERSIL® 577 PLUS is an emulsion. Proper stirring is recommended before the material is used. The material appears creamy and to certain extends nonyielding when filled into a feeding reservoir of the spraying equipment. The material shows a strong decrease of the viscosity under shear. That is why an addition of water to adjust the viscosity and the spraying behavior should be done carefully and very small doses.
Surface pretreatment
The insulator surface to be coated should be clean and free of dust and grease. For cleaning the following operations are suggested:
- Proper cleaning by using water and a suitable detergent might be sufficient.
- Insulators that show an adhering pollution, such like cement, other mineral or chemical pollution layers should be cleaned by either "cob corn-" or carbon dioxide blasting.
- Any type of grease or fatty pollution is to be removed by using a suitable solvent like benzine or turpentine.
- Residual contaminants should be removed by thoroughly wiping.
- Finish the cleaning just before spraying POWERSIL® 577 PLUS with Isopropanol or an equivalent alcohol.
Check carefully that there is no of dirt or grease left before spraying!
In most cases it is not necessary to apply a primer before coating.
POWERSIL® 577 PLUS is ideally applied by spraying. For spraying application, the airless process was found to be efficient. The following equipment settings were found to be suitable:
- Flat nozzle of 0,33 mm, 20°
- Setting of pressure output 50 - 150 bar
The spray gun should be moved evenly across the surface at a distance of about 30 - 50 cm. Due to the thixotropic properties of POWERSIL® 577 PLUS the coating is normally applied with one spray cycle.
A typical dry film thickness is 0,4 mm to 0,5 mm. Thus, the theoretical consumption is 0,8 kg to 1,0 kg of POWERSIL® 577 PLUS per square meter of insulator surface. Take losses for overspray and cleaning of the equipment into consideration.
Rain can damage the coating. In case of rain, please protect the job site or stop application.
All spraying equipment should be cleaned with water immediately after use.
Maintenance
The product contains migratable matter that is able to encapsulate contaminants and to provide a hydrophobic surface. Coated insulators may appear dirty after some time in service. Nevertheless, washing and cleaning, especially with detergents and other chemicals is not recommended.
Inspection
The water repellent appearance can be evaluated by spraying with water. IEC 62073, “Guidance on the measurement of wettability of insulator surfaces” provides further information. A partly lowering of the effect does not necessarily require immediate action. Experience shows that the remaining parts of the insulator will provide the necessary insulation ability.
Physical damage, such like scratching can be easily repaired by brushing of fresh coating after partly cleaning with benzine.
To allow an instant replacement of broken insulators it is recommendable to store a number of coated spare insulators. These should be stored in a protective covering.
