Naftoseal® MC-780 Class A is a two-component, manganese-dioxide cured, liquid polysulphide polymer system providing excellent fuel tank and fuselage seals. It has outstanding resistance to aviation gasoline and jet fuel, as well as resistance to chemicals and petroleum products common to the aircraft industry.
Naftoseal® MC-780 Class A maintains its flexibility and bond strength on most metal substrates like aluminium, stainless steel, steel, titanium and many coatings under extremes of temperature, weathering and stress.
The mixed compound is a pourable, slightly thixotropic liquid easily applied by extrusion, injection gun, spatula or brush. It has excellent tooling properties.
- Sealing integral fuel tanks
- Repairing integral fuel tanks
- Sealing fuselages
Download Naftoseal® MC-780 Class A technical datasheet
Application Life and Cure Time
(at 23°C/50% r.H.)
Application Life and Cure Time (at 23°C/50% r.H.) Type Min.Application Time Max.Tack-Free Time Time to Shore A 35 NAFTOSEAL ® MC-780 A - 1/2 0,5 hours < 4 hours < 8 hours MC-780 A - 1 1,0 hours < 7 hours < 10 hours MC-780 A - 2 2,0 hours < 14 hours < 24 hours
Typical Physical and Application Properties
Typical Physical and Application Properties base hardener Color grey brown Viscosity at 23°C,
Brookfield, Spindel 7
50 - 200 Pa.s
max. 400 Pa.s
Mixing ratio by weight 100 9 Mixing ratio by volume 100 6,4 Non-volatile content 92 ± 2 %
Typical Physical and Performance Properties
Typical Physical and Performance Properties of Cured Compound (after 14 days/23 °C) Color brown Specific gravity 1.25 g/ccm max Ultimate Shore A Hardness max 50 Shore A Service Temperatures -55 °C / +130 °C
Typical Values of MC-780 Class A
Typical Values of MC-780 Class A Conditioning Typical Values in N/mm2
Typical Values in % 14 days 23 °C ≥ 1,5 ≥ 200 6 months fuel / 23 °C ≥ 1,5 ≥ 200 Peel Strength (in N/25mm - % ) Adherend Conditioning Typical Values Al + Epoxy Primer 14 days 23 °C
300 h jet-fuel at 100 °C
≥ 120 N/25mm – 100%
≥ 120 N/25mm – 100%
To obtain good adhesion, clean surfaces with appropriate solvent (reclaimed solvents should not be used) to remove dirt, grease and processing oils just prior to sealant application. Use lint-free rags or paper towels that are free of oil.
Always pour solvent on the cloth to avoid contaminating the solvent supply. Clean one small area at a time, quickly wiping it dry before the solvent evaporates to prevent redeposition of oil, wax or other contaminants.
Usually, in the case of most epoxy resin primers, surfaces need not be additionally prepared with an adhesion promoter to improve adhesion. PUR and EP topcoats as well as composite components should be pre-treated by the NAFTOSEAL MC-115 Adhesion Promoter.
Cleaning of Equipment
Immediately after use or before the sealant cures, wash equipment and tools with a solvent. NAFTOSOLV FN will completely dissolve uncured, semi-cured and fully cured NAFTOSEAL sealants. It provides a method for completely removing NAFTOSEAL® and other polysulphide sealant contamination (see separate Data Sheet).
The material is supplied in the following containers
Packaging Designation Base Compound Content/Piece No./Case Kit 10 100 cm³ 12 Kit 25 250 cm³ 12 Kit 50 500 cm³ 12 Kit 100 1.000 cm³ 4 Techkit 55 55 cm³ 24 Techkit 130 130 cm³ 24 Unit 162 162 litri 9 x18 | Base + Hardener Drum 162 litri 162 | Base + Hardener
The shelf life of NAFTOSEAL® MC-780 Class A is 6 months from date of manufacture, when stored at temperatures below 26 °C in its original unopened container. Storage at lower temperatures increases shelf life.