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- DOWSIL™ 3-1953 Conformal Coating
DOWSIL™ 3-1953 Conformal Coating
- One-part, solventless silicone conformal coating
- UV indicator for inspection and quality assurance
- Soft, stress-relieving elastomer after cure
Product Description
DOWSIL™ 3-1953 Conformal Coating is a solventless, elastomeric silicone coating designed to protect printed circuit boards and electronic assemblies in lighting, industrial, and automotive applications. It provides reliable protection against moisture, corrosion, thermal cycling, and environmental contaminants while maintaining electrical insulation performance. The coating cures at room temperature through exposure to atmospheric moisture and forms a flexible elastomer that helps protect electronic assemblies under demanding operating conditions.
Key features
- Solventless silicone system - 100% silicone elastomer with no solvent carrier.
- Low-to-medium viscosity - Supports spray, dip, and selective coating application methods.
- Room-temperature cure - Cures through solvent evaporation followed by silicone crosslinking to form a durable elastomer.
- Flexible elastomer after cure - Helps reduce mechanical stress on solder joints and electronic components.
- Excellent environmental protection - Helps protect against moisture, corrosion, dust, and industrial contaminants.
- Electrical insulation performance - Provides reliable dielectric protection for electronic assemblies.
- UV indicator - Enables visual inspection and verification of coating coverage under UV light.
Applications
DOWSIL™ 3-1953 Conformal Coating is suitable for electronic assemblies where solvent-based silicone coating, uniform coverage of printed circuit boards, and UV-assisted 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.
- Sensitive electronics and fine-pitch designs: suitable for tightly spaced geometries where low-viscosity flow is required to achieve uniform coverage.
Related resources
Technical Specifications
| General Properties | |||||
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Color
Color
The color |
Translucent | ||||
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Specific Gravity
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. |
0.98 | ||||
| Physical Properties | |||||
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Viscosity
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 |
350 mPa.s | ||||
| Mechanical Properties | |||||
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Elongation
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. |
60 % | ||||
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| Electrical Properties | |||||
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Dielectric Strength
Dielectric Strength
Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material. Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property. As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow. |
17 kV/mm | ||||
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Volume Resistivity
Volume Resistivity
Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface. |
5.5x1015 Ohms⋅cm | ||||
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| Thermal Properties | |||||
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UL 94 Rating
UL 94 Rating
Flammability rating classification. It determines how fast a material burns or extinguishes once it is ignited. HB: slow burning on a horizontal specimen; burning rate less than 76 mm/min for thickness less than 3 mm or burning stops before 100 mm V-2: burning stops within 30 seconds on a vertical specimen; drips of flaming particles are allowed. V-1: burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. V-0: burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. 5VB: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may develop a hole. 5VA: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may not develop a hole |
V-0 | ||||
Additional Information
DOWSIL™ 3-1953 RTV Coating
DOWSIL™ 3-1953 Conformal Coating is a solvent-based 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 that enables uniform application across complex geometries and cures at room temperature primarily through solvent evaporation followed by silicone cure.
Review the technical data sheet and SDS before handling, processing, or qualifying the material.
Silicone Conformal Coating for Electronic Protection
DOWSIL™ 3-1953 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™ 3-1953 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 36 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
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.
Use the selection guide to compare DOWSIL™ conformal coating options by viscosity, cure profile, hardness, and agency listing context.
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.
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 | 350 350 0.4 |
cP mPa-sec Pa-sec |
| Specific Gravity (Cured) | 0.98 | |
| NVC (Non Volatile Content) | 99.4 | % |
| Tack-Free Time at 25ºC | 8 | minutes |
| Tack-Free Time at 60ºC/15% RH | 0.5 | minutes |
| Tensile Strength | 80 0.5 5 |
psi MPa kg/cm2 |
| Elongation | 60 | % |
| Durometer Shore A | 34 | |
| Dielectric Strength (JIS K 6249) | 3 | Volts/mil kV/mm |
| Dielectric Strength | 425 17 |
ohm*cm |
| Volume Resistivity (JIS K 6249) | 5.5 E15 | |
| Dissipation Factor at 100 Hz | 0.0007 | |
| Dissipation Factor at 100 kHz | < 0.0002 | - |
| Hardening Transition by DSC | -56.2 -49 |
F °C- |
| UL Flammability Classification | 94 V-0 | - |
| Mil Specification | Mil I-46058C Amend 7 | - |
| Agency Listing | IPC-CC-830A with Amendment 1, UL 746E |
- |
| Cyclotetrasiloxane (D4) content | < 0.1 | % |
Where DOWSIL™ 3-1953 fits
Tips and troubleshooting
| Issue | Recommended action |
|---|---|
| Air entrapment or voids |
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| Adhesion below target |
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| Curing |
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| Moisture exposure during storage |
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| Repair or rework requirement |
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Frequently asked questions about DOWSIL™ 3-1953 RTV Coating
What is DOWSIL™ 3-1953 RTV Conformal Coating used for?
It is used as a protective conformal coating for rigid and flexible circuit boards and PCB system applications, particularly where flexibility, abrasion resistance, dielectric protection, and room temperature cure are part of the application review.
How does this coating cure?
DOWSIL™ 3-1944 RTV Coating can be applied through brush, flow coat, or needle/dispense. It 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.