3M™ Aerospace Sealant AC-350 Class B are fast cure, intermediate density polysulfide sealant suitable for fuel tank and fuselage applications. These two-component, manganese dioxide cured sealants are solvent free and have outstanding resistance to aviation gasoline and jet fuel, as well as resistance to chemicals and petroleum products common to the aircraft industry. 3M™ AC-350 Class B Sealants maintain flexibility and bond strength on most metal substrates such as; aluminum, titanium, steel, stainless steel, glass, and many coatings under extremes of temperature, weathering and stress. The mixed compound is a thixotropic paste easily applied by extrusion, injection gun or spatula, and exhibits superb tooling properties.
Unit of Measure

Typical Physical and Application Properties

Base Color

N/A Off-White

Accelerator Color

N/A Brown

Mix Ratio (By Weight)

N/A 100 Base/10 Catalyst

Mix Ratio (By Weight) for Class B-1/4

N/A 100 Base/12.5 Catalyst

Non-Volatile Content

N/A 98 %
Base Viscosity1 N/A 9,000 to 12,000 Poise

Note for Typical Physical and Application Properties

N/A The technical information and data should be considered representative or typical only and should not be used for specification purposes.

Application Life and Cure Time at 77 Degree Fahrenheit (ºF) and 50 Percent (%) Relative Humidity

Class

N/A B-1/2 B-1/4 B-12 B-2 B-4 B-6

Minimum Application Life for Class B-1/4

N/A 15 min

Minimum Application Life for Class B-1/2

N/A 30 min

Minimum Application Life for Class B-2

N/A 2 hour

Minimum Application Life for Class B-4

N/A 4 hour

Minimum Application Life for Class B-6

N/A 6 hour

Minimum Application Life for Class B-12

N/A 12 hour

Note for Minimum Application Life

N/A Application life refers to the length of time that mixed compound remains at a consistency suitable for application with spatula or caulking gun. Application life is always measured at a standard temperature of 77ºF with a relative humidity level of 50 %. In general, for every 20º rise in temperature, the application life is halved; for every 20º drop, it is doubled. High humidity levels during the mixing process will shorten application life.

Typical Tack-Free Time for Class B-1/4

N/A 1 to 2 hour

Typical Tack-Free Time for Class B-1/2

N/A 2 to 3 hour

Typical Tack-Free Time for Class B-2

N/A 7 to 8 hour

Typical Tack-Free Time for Class B-4

N/A 32 to 36 hour

Typical Tack-Free Time for Class B-6

N/A 48 hour

Typical Tack-Free Time for Class B-12

N/A 96 hour

Note for Typical Tack-Free Time

N/A 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.

Typical Cure Time for Class B-1/4

N/A 1 to 2 hour

Typical Cure Time for Class B-1/2

N/A 2 to 3 hour

Typical Cure Time for Class B-2

N/A 7 to 8 hour

Typical Cure Time for Class B-4

N/A 32 to 36 hour

Typical Cure Time for Class B-6

N/A 48 hour

Typical Cure Time for Class B-12

N/A 96 hour

Note for Typical Cure Time

N/A Cure time is defined as the length of time it takes 3M™ Aerospace Sealant AC-350 Class B 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, heat may be applied up to (but not more than) 140ºF.

Typical Physical and Performance Properties of Cured Compound after 14 Days at 77 Degree Fahrenheit (ºF)/50 Percent (%) Relative Humidity

Mixed Color

N/A Dark Gray

Maximum Specific Gravity

N/A 1.40

Hardness

N/A 50 to 55 Shore "A"

Low Temperature Flexibility

N/A No cracking, checking or adhesion loss when tested at -65 ºF (-54 ºC)

Weight Loss in Josef Rakich Fitness (JRF)

N/A 3 to 4 %

Service Temperature

N/A -65 to +250 ºF-54 to +121 ºC

Short Term Service Temperature

N/A -65 to +360 ºF-54 to +182 ºC

Corrosion

N/A None

Thermal Rupture Resistance at 300 Degree Fahrenheit (ºF) Temperature and 30 Minutes (min) Time

N/A Conforms
Repairability2 N/A 50 piw/100% Cohesive Failure

Repairability to Aerospace Material Specification (AMS-S-8802) Sealants

N/A 67 piw/100% Cohesive Failure

Repairability to Aerospace Material Specification (AMS3276) Sealants

N/A 54 piw/100% Cohesive Failure

Crazing

N/A No effect on acrylic or polycarbonate

Specifications

Industry Focus

N/A Aerospace

Relative Humidity

N/A 50 %

Substrate Material

N/A Aluminum Glass Stainless Steel Steel Titanium

Material

N/A Polysulfide

Applications

N/A Repairing Integral Fuel Tanks Sealing Fuselages Sealing Integral Fuel Tanks

Health and Safety Precaution

Health and Safety Precaution

N/A 3M™ Aerospace Sealant AC-350 Class B are 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.

Storage

Storage

N/A The shelf life of 3M™ Aerospace Sealant AC-350 Class B is 9 months from date of packaging, when stored at temperatures below 80 ºF in its original unopened container.

Mixed 3M™ AC-350 Class B Sealants may be stored under refrigeration as follows:
  • 15 days at -10 ºF
  • 30 days at -40 ºF
It is important to remember that freezing, storing and thawing procedures reduce application life. Also, frozen storage will reduce application life by varying amounts depending on the storage temperature and length of storage time. All aspects of storage, freezing and thawing should be planned carefully and it is not recommended to mix and freeze with less than 1/2 hour of available application time.

Technical Information

Technical Information

N/A The technical information, recommendations and other statements contained in this document are based upon tests or experience that 3M™ believes are reliable, but the accuracy or completeness of such information is not guaranteed.

Product Use

Product Use

N/A Many factors beyond 3M™'s control and uniquely within user's knowledge and control can affect the use and performance of a 3M™ product in a particular application. Given the variety of factors that can affect the use and performance of a 3M™ product, user is solely responsible for evaluating the 3M™ product and determining whether it is fit for a particular purpose and suitable for user's method of application.

Warranty, Limited Remedy, and Disclaimer

Warranty, Limited Remedy, and Disclaimer

N/A Many factors beyond 3M™'s control and uniquely within user's knowledge and control can affect the use and performance of a 3M™ product in a particular application. Given the variety of factors that can affect the use and performance of a 3M™ product, user is solely responsible for evaluating the 3M™ product and determining whether it is fit for a particular purpose and suitable for user's method of application.

Limitation of Liability

Limitation of Liability

N/A Except where prohibited by law, 3M™ will not be liable for any loss or damage arising from the 3M™ product, whether direct, indirect, special, incidental or consequential, regardless of the legal theory asserted, including warranty, contract, negligence or strict liability.

Note

Note

N/A These products were manufactured under a 3M™ Quality Management System registered to the AS9100 standard.
  • 1 RVF Brookfield #7 spindle at 2 rpm, 77 ºF
  • 2 To itself