3M AC-770-B-2-3
Harmonization Code : 3506.91.90.99 | Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg ; Adhesives based on polymers of headings 3901 to 3913 or on rubber; Other ; Other
Main features
- Low Density Fuselage Sealing
- Controlled Thixotropic Placement
- Extended Class B Work Life
Product Description
3M Aerospace Sealant AC-770 Class B-2-3 is a two-part, low-density, manganese-dioxide-cured polysulfide sealant for aircraft fuselage sealing. Its thixotropic Class B paste supports extrusion, injection, and spatula placement while resisting flow after application. The system uses a 100:10 base-to-accelerator mix ratio by weight. Class B schedules include B-1 and B-2 grades, with B-2 providing a 2 hour application life at 77 deg F and 50% relative humidity. After cure, the dark-brown sealant remains flexible across a broad aerospace service temperature range.
Key features
- Low Density Fuselage Sealing: The cured sealant combines a 1.10 specific gravity with aircraft joint sealing.
- Thixotropic Application Control: Class B consistency supports extrusion, injection, and spatula placement.
- Extended B2 Work Life: The B-2 schedule provides a 2 hour application life under controlled conditions.
Applications
Aircraft fuselage joint sealing by extrusion, injection, or spatula application.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Thermal Properties
Other Properties
Additional Information
As-supplied / before-processing properties
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Base color | Off white | - | Before mixing |
| Accelerator color | Brown | - | Before mixing |
| Mix ratio by weight | 100:10 | base:accelerator | Class B system |
| Nonvolatile content | 98.5 | % | Typical |
| Base viscosity | 9500 to 13000 | poise | Brookfield RVT, spindle 7, 2 rpm, 77 deg F |
| B-2 schedule | 2; 7 to 8; 9 to 11 | h | Application life; tack-free time; cure time at 77 deg F and 50% relative humidity |
| Shelf life | 9 | months | Stored below 80 deg F |
After-processing / final-state properties
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Color | Dark brown | - | Cured 14 days at 77 deg F and 50% relative humidity |
| Specific gravity | 1.10 | - | Cured |
| Hardness | 42 to 48 | Shore A | Cured |
| Tensile strength | 250 | psi | Standard cure |
| Elongation | 310 | % | Standard cure |
| Service temperature range | -54 to 121 | deg C | Cured sealant |
