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3M Aerospace AC-250 Class A-1/6 Fuel Tank & Fuselage Sealant

3M Aerospace AC-250 Class A-1/6 Fuel Tank & Fuselage Sealant

Solve all of your integral fuel tank and fuselage needs with the use of 3M Aerospace AC-250 Class A-1/6 fuel tank and fuselage sealant from SkyGeek. This sealant is made up of two components. When mixed, these components form a pourable liquid compound, which can be administered to your aircraft with a spatula, extrusion gun or brush. This compound cures at low temperatures and provides a quick repair, making it ideal for fast fuel tank and fuselage repairs in the field. The consistency of the aerospace sealant allows the material to cover large areas quickly and effectively. After the curing process, the fuel tank sealant produces a resistant rubber coating.

Approvals, References and Specifications
  • AMS-S-83318
  • NA-66-1032


  • Low-temperature curing, quick repair, polysulfide sealant
  • Made up of two components
  • Designed for integral fuel tank and fuselage sealing applications
  • Mixed material is pourable liquid material
  • Can be applied with spatula, extrusion gun or brush
  • Covers large areas quickly and effectively
  • Reliable performance because of maintained flexibility and bond strength
  • Great for fast fuel tank and fuselage repairs in the field
  • Cures to fuel-resistant rubber at temperatures over 20 degrees Fahrenheit
  • Color: Base - white, Accelerator - dark brown
  • Mixing ratio: 100 base:10 accelerator (by weight)
  • 87 to 89 percent nonvolatile content
  • Application life: 10 minutes at 77 degrees Fahrenheit, 50 percent relative humidity
  • Typical tack-free time at 77 degrees Fahrenheit: 70 minutes
  • Typical cure time at 77 degrees Fahrenheit: 2 hours
  • Service temperature range: -65 degrees Fahrenheit to 250 degrees Fahrenheit
  • Retains flexibility at extremely low temperatures
Use Instructions
Two-Part Sealant Cartridges:

  1. Holding the cartridge, grasp the dasher rod and pull back approximately one inch

  2. Insert the ramrod into the hollow of the dasher rod, break the piston loose, and inject about 1/3 of the contents into the cartridge

    Note: Do not inject all of catalyst in one location. Distribute evenly throughout base material

  3. Repeat steps 2 and 3 until all the contents of the rod are emptied into the cartridge. Remove the ramrod

  4. Mix for the required number of strokes (hand mixing) or for the required amount of time (machine mixing) indicated in the kit instructions

  5. When mixing is complete, remove bottom cap

  6. Pull the dasher rod back to the neck of the cartridge, grasp the cartridge firmly at the neck, unscrew the dasher rod and remove

  7. Screw the nozzle into the cartridge, insert into the extrusion gun and use as required. For hand extrusion, press the used dasher rod against the plunger to force the material from the cartridge


The shelf life of AC-250 Class A is 6 months from date of packaging, when stored at temperatures below 80 degrees F in its original container.

Health and Safety Precautions

AC-250 Class A-1/6 sealant is safe to use and apply when recommended precautions are followed. Before using this product, read and understand the Material Safety Data Sheet (MSDS), which provides information on health, physical and environmental hazards, handling precautions and first aid recommendations. An MSDS is available on request. Avoid overexposure. Obtain medical care in case of extreme overexposure.

AMS-S-83318 - Qualified
NA-66-1032 - Qualified

Typical Physical and Application Properties

  • Color: Base - White, Accelerator - Dark Brown

  • Mixing Ratio: 100 base / 10 accelerator (by weight)

  • Nonvolatile Content: 87%-89%

  • Viscosity, poise (Brookfield #6 Spindle @ 2rpm): 1,000-4,000 poise

  • Application Life*: 10 mins at 77 degrees F, 50% relative humidity
  • Tack-Free and Cure Times

    At 77 degrees F

  • Typical Tack-Free Time**: 70 minutes

  • Typical Cure Time***: 2 hours
  • At 40 degrees F

  • Typical Tack-Free Time**: 7 hours

  • Typical Cure Time***: 8 hours
  • At 20 degrees F

  • Typical Tack-Free Time**: 12 hours

  • Typical Cure Time***: 14 hours
  • *Application life refers to the length of time that mixed compound remains at a consistency suitable for application with brush, spatula or caulking gun. Application life is always measured at a standard temperature of 77 degrees F with a relative humidity level of 50%. In general, for every 20 degree F rise in temperature, the application life is halved; and for every 20 degree F drop, it is doubled. High humidity levels during the mixing process will shorten application life.

    **Tack-free time is the length of time after which a mixed sealant will no longer tightly adhere to L-LP-690 standard low density polyethylene film.

    ***Cure time is defined as the length of time it takes AC-250 Class A sealant to reach 30A hardness. It depends on three factors: remaining application life, temperature and relative humidity. To a certain extent, the temperature/humidity factors for application life also apply to curing. To accelerate the curing process, apply heat up to (but not more than) 120 degrees F.

    Typical Physical and Performance Properties of Cured Compound* when tested to AMS-S-83318

  • Color: Gray

  • Specific Gravity: 1.64 (mixed)

  • Hardness: 55 Shore "A" (maximum)

  • Temperature Range: -65 degrees to +250 degrees F (-54 degrees to +121 degrees C)

  • Low Temperature Flexibility: No cracking, checking or adhesion loss when tested at -65 degrees F (-54 degrees C)

  • Fuel Rupsture Resistance: Retains Jet Reference Fluid 24 hours at 10 psig

  • Repeairability: Peel strength to AMS-S-8802 sealant is 35 piw

  • Corrosion Resistance: Does not cause corrosion

  • Fungus Resistance: Non-nutrient

  • Hydrolytic Stability: 40 Shore "A"

  • View DetailsEnable JS
    Part Number
    2.5 oz
    (Sold in increments of 24)
    Material Safety Data Sheet:
    Code: UN1866 | Class: 3 | Group: III - Click Here for Details
    View DetailsEnable JS
    Part Number
    3.5 oz Kit
    AMS-S-83318B Class A-1/6
    Material Safety Data Sheet:
    Code: UN1866 | Class: 3 | Group: III - Click Here for Details
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