Naftoseal® MC-780 Class C is a two-component, manganese-dioxide cured polysulfide polymer system with reduced density providing excellent fuel tank and fuselage seals. Part number 50563478 has 20 minutes minimum application time. It is designed for interfay surface sealing and wet riveting of fuselage components and has outstanding resistance to aviation gasoline and jet fuel, as well as resistance to the chemicals and petroleum products used in the aircraft industry. Additionally, it was developed for a service temperature between -55 °C (-67 °F) to +130 °C (+ 266 °F) and withstand a shortterm temperature of +182 °C (+360 °F). Naftoseal® MC-780 Class C maintains its flexibility and bond strength on most metal substrates like aluminium, stainless steel, steel, titanium, composite and many coatings under extremes of temperature, weathering and stress. Naftoseal® MC-780 Class C combines low viscosity, for ease of mixing, with a high thixotropy giving good application characteristics. It can be effectively applied by extrusion, by injection gun, or by using a roller coating technique. The low viscosity means that it is easily squeezed from interfaying surfaces during the assembly process and it has a unique self-filleting characteristic. The curing time may be reduced considerably by increasing the temperature (up to 60°C or 140°F max). Typical Physical and Application Properties BASE HARDENER Colour Beige Brown Viscosity at 23 °C, Brookfield RV, Spindel 7 Spindel 6 (for C-1/3 + C-2), all others spindel 7, 10 rpm 250 Pa•s. max. Spindel 7, 10 rpm 400 Pa•s. max Mixing ratio by weight 100 10 Mixing ratio by volume 100 7,26
