DOWSIL 93-076 RF

Harmonization Code : 3919.10.80 | Other self-adhesive plastic rolls not exceeding 20 cm wide.

DOWSIL 93-076 RF

Main features

  • Moisture and Weather Resistance
  • 2-Hour Working Window
  • 5.2 MPa Cured Tensile Strength

Product Description

DOWSIL™ 93-076 RF Sealant and Catalyst Kit is a two-part, thixotropic silicone elastomer for high-temperature aerospace sealing and bonding. The 10:1 by-weight system cures at room temperature and is supplied with catalyst options providing approximately 1/2-hour or 2-hour work time. It is documented for pressurization sealing, thermal barriers and insulative coatings, ablative-coating adhesion, cable breakout and termination protection, and formed-in-place seals.

Key features

  • High-temperature stability: Documented from -65°C to +260°C, with resistance to weathering, moisture, and ozone.
  • Controlled two-part processing: Mixes at 10 parts base to 1 part catalyst by weight, with 1/2-hour and 2-hour work-time catalyst options.
  • Aerospace application fit: Documented for pressurization seals, thermal barriers, insulative coatings, ablative-coating adhesion, cable protection, and formed-in-place seals.

Applications / Suitable for

  • High-temperature pressurization seals, thermal barriers, and insulative coatings.
  • Bonding of ablative coatings.
  • Cable breakout and termination protection and formed-in-place seals.
Product Family

DOWSIL 93-076 RF

Catalog Product

Unlike other products we offer, the products listed on this page cannot currently be ordered directly from the website.

TDS, SDS & Technical Documents

Technical Specifications

General Properties
ColorColor
Gray
Mix RatioMix Ratio
10:1
Physical Properties
ViscosityViscosity
360,000 (base) mPa.s
Mechanical Properties
ElongationElongation
400 %
Electrical Properties
Dielectric StrengthDielectric Strength
16 kV/mm
Volume ResistivityVolume Resistivity
1E13 Ohms⋅cm

Additional Information

Aerospace silicone sealant

DOWSIL™ 93-076 RF Sealant and Catalyst Kit

DOWSIL™ 93-076 RF Sealant and Catalyst Kit is a two-part, thixotropic silicone elastomer developed for high-temperature aerospace sealing and bonding. The 10:1 by-weight system combines room-temperature cure, selectable 1/2-hour or 2-hour work time, low thermal conductivity, and documented use in pressurization seals, thermal barriers, cable protection, formed-in-place seals, and bonding of ablative coatings.

Two-part thixotropic silicone 10:1 mix ratio by weight 1/2- or 2-hour work time Temperature stability: -65°C to +260°C Deep-section cure to 25 mm

DOWSIL™ 93-076 RF Sealant and Catalyst Kit

As-supplied and mixed properties

Base viscosity
360,000 mPa·s
High-viscosity, thixotropic base measured by CTM 0050 / ASTM D1084.
Mix ratio
10:1 by weight
Mix 10 parts base with 1 part selected catalyst by weight.
Property Value Unit Method / condition
Base color Gray   As supplied
1/2-hour work-time catalyst color Beige   As supplied
2-hour work-time catalyst color Blue   As supplied
Relative density 1.11   After catalyst addition at 25°C; CTM 0022 / ASTM D792
Application process

Mixing and cure

Process control is important for consistent adhesion, work time, deep-section cure, and final properties. Select the catalyst according to the required application window and keep surface preparation, mixing, de-airing, and cure conditions distinct.

Surface preparation and priming: Clean and lightly abrade suitable surfaces, rinse with acetone or methyl ethyl ketone, apply a thin coat of DOWSIL™ 1204 Primer, and allow at least 1 hour to dry depending on relative humidity. Silicone rubber is normally roughened and rinsed rather than primed.
Mixing and de-airing: De-air the base for 2 hours at greater than 650 mm Hg vacuum, add catalyst at 10:1 by weight in an air-free mixer, and avoid entrapped air. When hand mixed, de-air the mixture under vacuum for about 30 minutes.
Working and cure schedule: The catalyst options provide approximately 1/2-hour or 2-hour work time. Typical tack-free times are 4 and 14 hours, respectively. The sealant sets up in 24 hours at 25°C and reaches optimum physical properties in 5 days. Heat can accelerate handling cure to 4 hours at 85°C or 2 hours at 95°C, but full physical properties are not obtained from these short heat schedules alone.
Storage and Handling

Store unopened kits at or below 32°C; usable life is 9 months from the date of production. After catalyst addition, the mixed sealant remains usable for about 2 weeks when stored immediately at -40°C or below. Keep the moisture-sensitive catalyst covered, minimize container opening, and do not use catalyst that has become grainy or crystalline. Kit net weights are 0.45 kg, 4.1 kg, and 20.4 kg. Review the current safety data sheet and container labels before handling.

Surface preparation and confined-section guidance

Substrate and primer boundary
The sealant is documented to adhere to primed glass, cork, phenolic, polyester, epoxy, silicone-resin laminates, stainless steel, titanium, aluminum, and other aerospace materials. For good adhesion, use DOWSIL™ 1204 Primer on substrates other than silicone rubber. Polyethylene and materials that bleed plasticizers may give poor adhesion; application testing remains necessary.
Deep sections and total confinement
Deep-section cure is reported at 25 mm thickness. Tin-catalyzed silicone can depolymerize when a thick section is overheated in total confinement. For encapsulations requiring extended elevated-temperature service in total confinement, use a graduated post-cure with an approximate 25°C-per-hour temperature increase and a final 4-hour bake at 50°C above the device maximum operating temperature. Contact Dow for alternate-product guidance when the risk must be eliminated.

Cured performance

Tensile strength
5.2 MPa
Typical cured tensile strength measured by CTM 0137A / ASTM D412.
Elongation at break
400%
Typical cured elongation measured by CTM 0137A / ASTM D412.

Typical values are not intended for use in preparing specifications. Preserve the stated methods and conditions when evaluating the data.

Property Value Unit Method / condition
Lap shear strength 2.3 MPa CTM 0293; bond-strength values reported on primed 2024-T3 aluminum
Durometer hardness 46 Shore A CTM 0099 / ASTM D2240
Tear strength, die B 25 kN/m CTM 0159A / ASTM D624
Peel strength 12 kN/m CTM 0293; 1.5 mm glue, 6 mm cold-rolled steel
Brittle point -68 °C Typical value
Cure time 24 hours At 25°C; optimum physical properties after 5 days
Volume resistivity 1 × 10¹³ ohm·cm After catalyst addition
Permittivity 3.2   At 100 Hz; CTM 0112 / ASTM D150
Permittivity 3.2   At 100 kHz; CTM 0112 / ASTM D150
Dissipation factor 0.01   At 100 Hz; CTM 0112 / ASTM D150
Dissipation factor 0.01   At 100 kHz; CTM 0112 / ASTM D150
Dielectric strength 16 kV/mm CTM 0114 / ASTM D149
Ablation char retention Poor   45 W/cm² oxyacetylene torch
Ablation penetration rate 0.02 mm/s 45 W/cm² oxyacetylene torch
Ablation char retention Good   850 W/cm² oxyacetylene torch
Ablation penetration rate 1.39 mm/s 850 W/cm² oxyacetylene torch
use contexts

Aerospace sealing and bonding applications

The product is documented for high-temperature aerospace sealing, insulation, protection, and bonding roles. Final suitability depends on the substrate, surface preparation, section geometry, catalyst choice, cure schedule, and service conditions.

High-temperature aerospace pressurization sealing application
Pressurization seals and thermal barriers
Use as a high-temperature pressurization sealant, thermal barrier, or insulative coating where the documented silicone properties and cure process fit the assembly requirements.
Ablative coating bonded to an aerospace structure
Ablative-coating adhesion
Use as an adhesive for ablative coatings, with adhesion evaluation tied to the actual substrate, primer, bondline, cure, and thermal-exposure configuration.
Protected aerospace cable breakout and formed-in-place seal
Cable protection and formed-in-place seals
Use to protect cable breakouts and terminations and to fabricate formed-in-place seals in aerospace and aircraft assemblies.

Product resources

Dow Adhesives and Sealants Selection Guide
Selection guidance for advanced silicone adhesives and sealants, including cure-system and performance considerations for electronics and assembly applications.
View resource
Dow Aerospace, Defense & Avionics Product Selection Guide
Aerospace portfolio guide covering silicone solutions for aircraft, defense, avionics, spacecraft, and satellite applications, including DOWSIL™ 93-076 RF Aerospace Sealant.
View resource
Next steps

Technical support

Need help evaluating DOWSIL™ 93-076 RF for a pressurization seal, thermal barrier, cable termination, formed-in-place seal, or ablative-coating bond? Krayden can help review substrate preparation, catalyst choice, work time, cure schedule, section geometry, and test requirements for your aerospace application.

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