DOWSIL™ 3145 RTV Mil-A-46146 Adhesive/Sealant

Main features

Military-grade
High strength
Non-flowing paste

Product Description

DOWSIL™ 3145 RTV MIL-A-46146 Adhesive Sealant is a high-strength, one-part silicone solution available in clear and gray, specifically engineered for the rigorous demands of military and aerospace electronics. This non-flowing (non-sag) paste cures at room temperature upon exposure to atmospheric moisture, eliminating the need for curing ovens. Designed to provide long-term bonding and protection against mechanical shock, vibration, and thermal cycling, it maintains exceptional stability across a broad temperature range of -50°C to +200°C.

Product Key Features

Military Grade: fully meets the requirements of MIL-A-46146 Group II/III, Type I specifications.
High Strength: delivers exceptional tensile strength (up to 1,035 psi) and high elongation (up to 670%) for durable structural bonds.
Non-Flowing Paste: non-sag consistency allows for precise application on vertical or overhead surfaces without slumping.
Thermal Stability: remains flexible and stable from -50°C up to +200°C, with the gray version offering even higher thermal limits.
Excellent Dielectric Properties: provides reliable electrical insulation for sensitive electronic sub-assemblies.
Easy Processing: one-part moisture cure system requires no mixing and features a tack-free time of approximately 60–90 minutes.
Primerless Adhesion: formulated to bond well to many reactive metals, glass, ceramics, and silicone rubber.

Key Applications

Sealing openings in modules, housings, and aircraft panels.
Adding mechanical stability to individual components on Printed Wiring Boards (PWBs).
Sealing in and around wired leads and electrical connectors to prevent environmental contamination.
Aviation MRO and AOG repairs requiring rapid, high-strength sealing.

TDS, SDS & Technical Documents

11-3215-01-dowsil-3145-rtv-mil-a-46146-adhesive

English (Technical Data Sheet (TDS))

Technical Specifications

General Properties

Color

Clear/ Gay

Specific Gravity

1.1 - 1.12

Physical Properties

Viscosity

862000 (Low Shear - 1/s) mPa.s

Mechanical Properties

Elongation

626 - 670 %

Electrical Properties

Dielectric Strength

19.09 kV/mm

Volume Resistivity

4.4e+14 Ohms⋅cm

Thermal Properties

Glass Transition Temperature (Tg)

-42 °C

Additional Information

One-part silicone adhesive sealant

DOWSIL 3145 RTV MIL-A-46146 Adhesive Sealant - Clear

A clear, one-part PDMS adhesive sealant with a non-flowing consistency and room-temperature moisture cure. It is documented for module and housing sealing, PWB component assembly, and sealing around wired and electrical leads. Typical cured data combine high elongation with tensile, tear, and dielectric performance, and the product is identified as MIL-A-46146 Group II, TY I.

Clear PDMS adhesiveOne-partNon-flowingRoom-temperature cureTack-free 63.8 min

As supplied

Typical application and handling properties

Typical values are not intended for use in preparing specifications.

Property	Value	Unit	Method / condition
One or two-part	One	-	As supplied
Color	Clear	-	As supplied
Extrusion rate	78.6	g/min	Typical value
Viscosity	862	Pa-sec	Low shear, 1/s
Viscosity	168	Pa-sec	High shear, 10/s
Flow rate - slump	0.092	in	Typical value
Tack-free time	63.8	minutes	25 deg C
NVC (non-volatile content)	96.9	%	Typical value

Processing

Room-temperature moisture cure

DOWSIL 3145 RTV cures from the exposed surface inward using moisture in the air. Surface preparation, open exposure to atmospheric moisture, and section geometry are important processing considerations.

Cure environment: Room-temperature cure in 30 to 80% relative humidity.

Tack-free time: 63.8 minutes at 25 deg C.

Cure progression: Moisture cure proceeds from the exposed surface inward; the TDS describes a typical rate of 0.25 inch per seven days for this adhesive type.

Optional acceleration: Mild heat below 60 deg C may be used to increase throughput by accelerating cure.

Application sequence

Preparation and application sequence

Stage 1

Prepare the surfaces

Thoroughly clean and degrease surfaces. The TDS lists Dow OS Fluids, naphtha, mineral spirits, MEK, or another suitable solvent. Light abrasion is recommended when possible, followed by a final wipe with acetone or IPA.

Stage 2

Dispense the adhesive

Apply by automated or manual needle dispense. Because cure progresses from the exposed surface inward, the applied adhesive must retain access to atmospheric moisture.

Stage 3

Allow moisture cure

Cure at room temperature under ambient moisture. Avoid highly confined or deep sections when moisture access is limited. Mild heat below 60 deg C may be used to accelerate cure.

Storage and handling

Protect the material from moisture during storage

Store at or below the storage temperature listed on the product label in the original package with the cover tightly attached. Minimize moisture exposure and headspace; partially filled containers should be purged with dry air or another dry gas such as nitrogen. Use the product by the Use Before date shown on the label.

Technical guidance

Technical guidance for product evaluation

Useful temperature range

For most uses, the documented operational range is -45 to 200 deg C for long periods. Low-temperature cycling to -55 deg C may be possible but should be verified for the specific part or assembly. At high temperature, durability is time and temperature dependent.

Adhesion and substrate evaluation

The product is formulated for unprimed adhesion to many reactive metals, ceramics, glass, and selected laminates, resins, and plastics. Adhesion can be limited on non-reactive metals and surfaces such as Teflon, polyethylene, or polypropylene. Small-scale substrate testing is recommended before production trials.

Cure-depth and solvent boundaries

Moisture-cure behavior makes highly confined spaces and deep-section cures less suitable. The adhesive is intended to survive splash or intermittent solvent exposure and is not suited for continuous solvent or fuel exposure. Application-specific testing is required for these conditions.

Cured properties

Mechanical and electrical properties

Typical cured values are not intended for use in preparing specifications.

Property	Value	Unit	Method / condition
Specific gravity	1.10	-	Cured
Tensile strength	864	psi	Typical cured value
Elongation	626	%	Typical cured value
Tensile modulus	138	psi	Typical cured value
Tear strength	223	ppi	Die B
Durometer	45.6	Shore A	Typical cured value
Unprimed adhesion - lap shear to aluminum	336	psi	Equivalent source values: 2.32 MPa and 232 N/cm^2
Dielectric strength	485	volts/mil	Typical cured value
Volume resistivity	4.4 E+14	ohm*cm	Typical cured value
Dielectric constant	2.83	-	100 Hz
Dielectric constant	2.83	-	100 kHz
Dissipation factor	0.0005	-	100 Hz
Dissipation factor	< 0.0002	-	100 kHz

Applications

Documented electronics sealing and assembly uses

The supplied TDS identifies three application areas for DOWSIL 3145 RTV. Final substrate, geometry, cure access, and service conditions should be evaluated for the specific assembly.

Modules and housings

Sealing openings in modules and housings where a one-part, non-flowing moisture-cure silicone is appropriate for the assembly design.

Printed wiring board assembly

Assembly of components on printed wiring boards using a clear adhesive sealant with room-temperature cure and no mixing requirement.

Wired and electrical leads

Sealing in and around wired and electrical leads where the documented dielectric properties and non-flowing form are relevant to product evaluation.

Next steps

Evaluate DOWSIL 3145 RTV for your assembly

Contact Krayden to discuss substrate compatibility, moisture-cure access, dispense approach, service-temperature conditions, or MIL-A-46146 documentation for your specific assembly. The technical team can also help review whether the documented mechanical and dielectric properties align with your application and qualification requirements.