DOWSIL 3-6891

Harmonization Code : 2901.10.00.00 | Acyclic hydrocarbons; Saturated

DOWSIL 3-6891

Main features

  • Machinable Abradable Rubber
  • 0.95 Cured Specific Gravity
  • Two-Hour 300 deg F Cure

Product Description

DOWSIL 3-6891 Abradable Sealant starts as a black, flowable one-part silicone and heat-cures into a low-density, flexible and machinable rubber. A Brookfield viscosity of 2,300 poise supports casting, troweling or injection with standard one-component equipment, while a two-hour cure at 300 deg F establishes the condition for the cured-property values. The cured material combines a specific gravity of 0.95, Shore A 71 hardness, 580 psi tensile strength and 0.24 W/(m K) thermal conductivity. Applications include abradable seals, compressor-blade rubstrips and high-temperature thermal insulation.

Key features

  • Abradable cured rubber: The heat-cured material can be machined for controlled seal clearance.
  • Low-density final state: Typical cured specific gravity is 0.95.
  • Heat-cure processing: Cured-property values use a two-hour cure at 300 deg F.

Applications

Abradable seals, compressor-blade rubstrips and high-temperature thermal-insulation applications.

Product Family

DOWSIL 3-6891

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Appearance
Appearance at room temperature.
Black, flowable liquid
Specific Gravity
Specific gravity (SG) is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume. For liquids, the reference substance is almost always water (1), while for gases, it is air (1.18) at room temperature. Specific gravity is unitless.
0.95
Physical Properties
Viscosity
Viscosity is a measurement of a fluid’s resistance to flow. Viscosity is commonly measured in centiPoise (cP). One cP is defined as the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP. A product like honey would have a much higher viscosity -around 10,000 cPs- compared to water. As a result, honey would flow much slower out of a tipped glass than water would. The viscosity of a material can be decreased with an increase in temperature in order to better suit an application
230,000 mPa.s
Mechanical Properties
Elongation
Elongation is the process of lengthening something. It is a percentage that measures the initial, unstressed, length compared to the length of the material right before it breaks. It is commonly referred to as Ultimate Elongation or Tensile Elongation at break.
70 %
Thermal Properties
Thermal Conductivity
Thermal conductivity describes the ability of a material to conduct heat. It is required by power packages in order to dissipate heat and maintain stable electrical performance. Thermal conductivity units are [W/(m K)] in the SI system and [Btu/(hr ft °F)] in the Imperial system.
0.24 W/m.K

Additional Information

Technical properties

As-supplied / before-processing properties

Typical as-supplied and storage properties. Values are not specifications.

Property Value Unit Method / condition
Physical form Flowable liquid As supplied
Appearance Black As supplied
Viscosity 2300 poise Brookfield HAF #7 at 10 rpm
Shelf life 12 months Original unopened container
Storage temperature 15-40 deg F Original unopened container
Package size 3.6 kg Pail
Technical properties

After-processing / final-state properties

Typical properties after a two-hour cure at 300 deg F.

Property Value Unit Method / condition
Physical form Flexible rubber After heat cure
Specific gravity 0.95 After heat cure
Durometer hardness 71 Shore A After heat cure
Tensile strength 580 psi After heat cure
Elongation 70 % After heat cure
Lap shear adhesion 320 psi Aluminum; 100% cohesive failure
Thermal conductivity 0.24 W/(m K) After heat cure
Coefficient of thermal expansion 1.75 x 10^-4 m/m deg C After heat cure

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