DOWSIL™ 3-1965 Conformal Coating

Harmonization Code : 3208.20.90 |   Paints and varnishes that are dispersed or dissolved in a non aqueous medium
Main features
  • One-part silicone conformal coating
  • Flexible cure options: room temperature or heat-accelerated
  • Wide operating temperature range (-55°C to 200°C)

Product Description

DOWSIL™ 3-1965 Conformal Coating is a one-part, no-added-solvent silicone conformal coating designed for protective coating of printed circuit boards and electronic assemblies. It provides very low viscosity (approximately 115 cP) for excellent flow into fine features and complex geometries, cures at room temperature through exposure to atmospheric moisture, and can be heat-accelerated to support manufacturing efficiency. Once cured, it forms a soft, flexible elastomer that provides electrical insulation, environmental protection, and stress relief for sensitive electronic components and densely populated PCB designs, subject to application-specific testing and qualification.

Key features

  • Very low viscosity - ~115 cP enables excellent flow into tight spaces, fine-pitch components, and complex PCB geometries.
  • Moisture-cure RTV system - Cures at room temperature through exposure to atmospheric moisture with optional heat acceleration.
  • No-added-solvent formulation - Helps reduce process complexity and supports cleaner coating operations.
  • Soft elastomer after cure - Low-stress silicone material helps protect sensitive components and solder joints.
  • Excellent coverage performance - Flows easily under and around densely populated electronic assemblies.
  • Electrical insulation properties - Provides reliable dielectric protection for PCB assemblies.
  • UV indicator - Enables inspection and verification of coating coverage under UV light.

Applications

DOWSIL™ 1-2620 Low VOC Conformal Coating is suitable for electronics assemblies where low-viscosity silicone coating, circuit-board protection, and coating inspection are part of the application review.

  • Rigid and flexible circuit boards: suitable for protective coating of printed circuit boards and PCB system applications.
  • PCB assembly protection: supports environmental protection, corrosion resistance, and dielectric protection requirements.
  • Printed Wiring Boards (PWB): low-viscosity flow is required to ensure uniform coverage of circuit traces, solder joints, and component leads
  • Sensitive electronics and fine-pitch designs: suitable for tightly spaced geometries where low-viscosity flow is required to achieve uniform coverage.

Related resources

Product Family
DS-31965  
3.6Kg Pail
Clear

Catalog Product

Unlike other products we offer, the products listed on this page cannot currently be ordered directly from the website.
Shipping in 5 weeks
Packaging
TDS, SDS & Technical documents

Technical Specifications

Additional Information

moisture cure conformal coating

DOWSIL™ 3-1965 RTV Coating

DOWSIL™ 3-1965 Conformal Coating is a one-part, transparent, no-added-solvent silicone conformal coating designed to protect printed circuit boards and electronic assemblies from moisture, corrosion, thermal cycling, and environmental contaminants. The coating features a low viscosity of approximately 115 cP, cures at room temperature through exposure to atmospheric moisture, and can be heat-accelerated to support manufacturing efficiency.

one part 115 cP viscosity MIL-I-46058C IPC-CC-830

Review the technical data sheet and SDS before handling, processing, or qualifying the material.


DOWSIL™ 3-1965 RTV Coating
RTV Coatings

Silicone Conformal Coating for Electronic Protection

DOWSIL™ 3-1965 RTV Coating cures upon exposure to atmospheric moisture, eliminating the need for solvent evaporation during processing. Its room-temperature cure can be accelerated with mild heat to support faster production cycles. The coating's high-viscosity, self-leveling formulation is suitable for a range of application methods and provides consistent coverage of electronic assemblies.

As a cured elastomer, DOWSIL™ 3-1965 RTV Coating delivers excellent flexibility and low-modulus properties, helping to minimize mechanical stress on sensitive components, solder joints, and interconnections during thermal cycling and environmental exposure.

Key features

  • Room-temperature cure - Cures through solvent evaporation followed by silicone crosslinking.
  • Solvent-free formulation - 100% solids silicone system with no solvents or by-products.
  • Low viscosity coating - Supports spray, dip, and selective coating application methods
  • Flexible elastomer after cure - Shore A 33 material reduces mechanical stress on sensitive components and solder joints.
  • UV indicator - Facilitates inspection and verification of coating coverage under UV light.
  • Reliable environmental protection - Provides resistance to moisture, corrosion, and contaminants in harsh environments.

Processing summary

Mix ratio: one part
Working time at 25°C: 20 minutes, listed as pot life in the technical data sheet.
Cure: 24 hours at 25°C.
Application method: spray, brush flow, automated pattern coating, can be dip coated with special precautions.
Product resources

Product Documents and Dow Coating Resources

Review the technical data sheet for typical product properties, the safety data sheet for handling and storage requirements, and the Dow conformal coatings selection guide for broader context on the coating family.

Conformal Coatings Selection Guide

Use the selection guide to compare DOWSIL™ conformal coating options by viscosity, cure profile, hardness, and agency listing context.

What this selection guide covers

The Dow conformal coatings selection guide explains how silicone coatings are positioned by viscosity, cure profile, hardness, stress relief, abrasion resistance, UV inspection, and agency listing context. It also includes a solventless coating section for applications where reducing solvent-handling complexity is a key selection driver, along with comparison tables for solventless RTV, solventless heat-cure, and solvent-based RTV conformal coatings.

Typical properties

Performance Properties

Cure basis and test conditions are per technical data sheet unless otherwise stated.

Property Typical value Unit
One or Two Part One  
Color Translucent  
Viscosity 115
0.1		 cP
Pa-sec
Specific Gravity (Cured) 0.99  
Tack-Free Time at 25ºC 6 minutes
Durometer Shore A 34  
Dielectric Strength  425
17		 Volts/mil
kV/mm
Volume Resistivity 8.7 E14 ohm-cm
Dissipation Factor at 100 Hz 0.001  
Dissipation Factor at 100 kHz < 0.0002 -
UL Flammability Classification 94 V-0 -
Mil Specification Mil I-46058C Amend 7 -
Agency Listing IPC-CC-830 with
Amendment 1		 -
Cyclotetrasiloxane (D4) content < 0.1 %
Storage and handling, per technical data sheet
Shelf life is indicated by the Use Before date on the product label. Refer to the product label for storage temperature requirements. Containers should be kept tightly closed and headspace minimized. Partially filled containers should be purged with dry air or other gases such as nitrogen. Exposure to moisture could reduce adhesion and cause bubbles to form.
Applications

Where DOWSIL™ 3-1965 fits

Rigid and flexible circuit boards
May be considered for conformal coating of rigid and flexible circuit boards where protection against moisture ingress, thermal cycling stress, and mechanical flexing is required to maintain electrical integrity and long-term reliability in demanding operating environments.
Printed wiring boards (PWB)
May be considered for conformal coating of printed wiring boards (PWBs) where uniform environmental sealing of circuit traces, solder joints, and component interfaces is required to prevent corrosion, contamination, and electrical leakage over the service life of the assembly.
Sensitive components and fine pitch designs
May be considered for conformal coating of sensitive components and fine-pitch designs where precise coverage of densely packed features is required while minimizing mechanical stress on delicate interconnects and maintaining reliable electrical insulation in compact assemblies.
Technical guidance

Tips and troubleshooting

Issue Recommended action
Air entrapment or voids
  • Minimize air entrapment during pouring or dispensing.
  • Use vacuum dispensing when practical, especially for assemblies with small voids.
  • Evacuate the unit after dispensing when vacuum dispensing cannot be used.
Adhesion below target
  • Clean and dry substrates before conformal coating application.
  • With RTV cure coatings, adhesion lags behind cure and may take up to 72 hours to build.
    On certain difficult, low-surface-energy surfaces, adhesion may be improved by priming or by special surface treatment such as chemical or plasma etching. 
Curing
  • Time to cure will depend on the method of application, film thickness, temperature, and humidity.
  • Cure time for full cure is an indication of time needed to develop full physical properties, such as durometer, tensile strength or adhesion.
  • These times, including full cure time, can be significantly improved by introducing mild heat of 60°C or less. 
Moisture exposure during storage
  • Keep containers tightly closed.
  • Minimize headspace after opening.
  • Purge partially filled containers with dry air or nitrogen where appropriate.
Repair or rework requirement
  • Cut and remove unwanted cured elastomer from the repair area.
  • Remove adhered elastomer by mechanical scraping or rubbing as needed.
  • Roughen exposed cured surfaces, rinse with suitable solvent, and dry before recoating.
FAQ

Frequently asked questions about DOWSIL™ 3-1965 RTV Coating

What is DOWSIL™ 3-1965 RTV Conformal Coating used for?

It is used to protect printed circuit boards and electronic assemblies from moisture, corrosion, and environmental contaminants while providing electrical insulation and long-term reliability, especially in fine-pitch and densely populated designs..

How does this coating cure?

DOWSIL™ 3-1965 RTV Coating cures by atmospheric moisture at room temperature. Mild heat can be used to accelerate processing after sufficient solvent flash-off.

Which application methods are supported?

DOWSIL™ 3-1944 RTV Coating can be applied through brush, flow coat, or needle/dispense. Process fit should be confirmed against the target wet-film thickness, board layout, masking approach, and keep-out areas.

What does the UV indicator confirm?

The UV indicator supports inspection of coating presence. It should not be treated as proof of final dry-film thickness, full cure, adhesion, absence of defects, or long-term electrical reliability.

Next steps

Review DOWSIL™ 3-1965 for your conformal coating application

Share your substrate materials, application method, coating thickness requirements, cure constraints, electrical performance requirements, environmental exposure conditions, and any industry compliance needs so DOWSIL™ 3-1965 RTV Coating can be evaluated against your application-specific qualification plan.