Coating for Low Wattage Wire Wound Resistors
R C Varnish is Alkyd Melamined based system specially formulated for coatings of low wattage wire wound resistors, Potentiometer etc. These coatings have following advantage over conventional Epoxy and Vitreous coating.
- Curing possible at temperature where temperature is not more than 120°C
- Resistance to humidity and corrosive atmosphere
- Simplicity in application technique
Properties
- Appearance : Grey
- Solid CONTENTS : 51 ± 1 % (120°C/ 1 hrs / 2gm)
- Viscosity by BF / 27°C : 200 – 250 mPa.s
Method of Application
- The coating is applied to resistor by dipping. Allow the solvent to evaporate by keeping it at RT for 15 –30 minutes. After complete removal of solvent, Job can be transferred to air circulating oven for curing. Curing cycle is recommended as follows
Recommended Curing Schedule
- First dip air drying for 15 – 30 minutes
- Followed by curing at 120°C – 30 minutes / 150°C– 10 minutes
The resistors will pass dielectric, heat ageing and humidity test as per specification