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Description for Dow Firestop 3-6548 Silicone RTV Foam
Forms complex, irregular shapes; long service life; resistant to ozone, ultra-violet radiation and temperature extremes; up to a 4 hour fire rating can be achieved.Application Type Coat, Seal 1 Part or 2 Part 2-Part Material Form Liquid Industry Housing and Assembly, Advanced driver-assistance systems (ADAS), E-Mobility Solutions, Consumer Goods Manufacturer Dow Chemistry Silicone Cure Method Part A/Part B Cure Temperature (°C) 20 to 25 Color Dark gray-black, Dark gray-black Other Resistance Reversion Volume Resistivity (O) 2.24e15 (ohms/cm) Density (g/cm³) Medium, 0.220 to 0.320 -
Technical Data for Dow Firestop 3-6548 Silicone RTV Foam
Overview
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1 Part or 2 Part
- 2-Part
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Material Form
- Liquid
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Industry
- Consumer Goods
- Housing and Assembly
- Advanced driver-assistance systems (ADAS)
- E-Mobility Solutions
- Industrial - Preparing fire-resistant penetration seals
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Chemistry
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Cure Method
- 2-Part Cure - Part A/Part B
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Color
- Black - Dark gray-black
- Gray - Dark gray-black
Specifications
Cure Specs
Cure Temperature (°C) 20 to 25 Work / Pot Time (min) 1.00 to 2.00 Test Method Mix Ratio 1:1 (by volume), 1:1 (by weight) Bond Strength
Tensile Strength (psi) 33 Test Method Material Resistance
Flame Resistance Fire Resistance UV Resistance Ultra-violet radiation Other Resistance Reversion Conductivity
Dissipation Factor 0.00505 Test Method Dielectric Strength (V/mil) 165 Test Method Dielectric Constant 1.95 Test Method Thermal Conductivity (W/m°K) 0.41 Test Method Volume Resistivity (O) 2.24e15 (ohms/cm) Test Method Other Properties
Specific Gravity 1.050 to 1.110 Test Method Coefficient of Thermal Expansion (CTE) 1.78e-4 (in./ in/°F) Test Method Density (g/cm³) Medium, 0.220 to 0.320 Test Method Business Information
Shelf Life Details When stored in unopened containers at or below 32°C (90°F), Dow Corning 3-6548 Silicone RTV Foam has a shelf life of 12 months from date of shipment from Dow Corning. Refer to product packaging for “Use By” date., Partially used containers should be sealed tightly and stored in a similar manner. Shelf Life Type from date of shipment Shelf Life (mon) 12 -
Best Practices for Dow Firestop 3-6548 Silicone RTV Foam
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Surface Preparation
The penetration opening and all related surfaces must be clean of dirt, dust and loose impediments. Surfaces must also be free of water, oil or other free liquids.
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Mixing
Prior to use, Part A and Part B components must be thoroughly stirred in their original containers to uniformly disperse any fillers or pigments that may have settled. When mixing, use clean containers and mixing equipment. If stirred containers stand for more than four hours, re-stir. At time of installation, material temperature should be between 18 and 27°C (65 and 81°F). (Materials can be warmed by placing them in a room at these temperatures for 12 hours.) Please check material temperature prior to use if there is a possibility it is outside this range. To properly catalyze Dow Corning 3-6548 Silicone RTV Foam, add Part A to Part B in a 1:1 ratio (by weight or volume). Mix vigorously and thoroughly for 30 to 60 seconds by hand or with power mixing. The mixed product will begin to foam shortly after mixing
therefore, it should be dispensed in the penetration as soon as mixing is completed. For large-volume applications, the use of suitable automatic mixing, metering and dispensing equipment is recommended. A list of equipment manufacturers is available from Dow Corning. The type and degree of mixing can significantly affect the cell structure and density of the final foam product. Mixing with a 198-g (7-oz) Semco® cartridge will generally result in a slightly higher density than mixing by hand. Hand mixing, in turn, will result in a higher density than power mixing by automatic mixing, metering and dispensing equipment. Likewise, the expansion ratios of foam volume to liquid volume can vary from 2:1 to 4:1, depending on the type and degree of mixing and degree of confinement. If foam rise is restricted or confined during foam cure, densities as high as 0.48 g/cm3 (30 lb/ft3) can result.
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Clean-Up
Excess cured foam around the penetration seal can be removed with a sharp knife or blade. Spills of Part A and Part B liquid components can be removed with high-flash-point mineral spirit solvent. Caution: Consult solvent material data sheet for safe handling information. Follow state, federal and local environmental regulations.
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Comparable Materials for Dow Firestop 3-6548 Silicone RTV Foam
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Work / Pot Time Test Methods
Work / Pot Time | Test Method | Temperature |
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1.00 to 2.00 min | CTM 092A,One part A thoroughly mixed with one part B and cured at 25°C 77°F for 24 hours.,Time to nonpour condition. Also, time to begin foam rise., Standard procedures for measuring snap time and free foam density are available from Dow Corning. Totally unconfined, density values as low as 0.22 g/cm3 14 lb/ft3 may be obtained. Values shown are typical for field installation | 25°C |
Tensile Strength Test Methods
Tensile Strength | Cure Time | Cure Temperature | Test Method |
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33 psi | 1,440 min | 25°C | ASTM D 3574, One part A thoroughly mixed with one part B and cured at 25°C (77°F) for 24 hours.,Other: Testing on what we believe to be a representative lot of material. Testing is not done on a lot-by-lot basis. If property is critical for your application, you should test on a lot-by-lot basis prior to use. |
Dielectric Constant Test Methods
Dielectric Constant | Test Method |
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1.95 | (100 Hz), CTM 0112, Cured foam sample thickness of 0.317 cm (0.125 inch). |
Dielectric Strength Test Methods
Dielectric Strength | Test Method |
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165 V/mil | CTM 0114, Cured foam sample thickness of 0.317 cm (0.125 inch). |
Dissipation Factor Test Methods
Dissipation Factor | Test Method |
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0.00505 | (100 Hz), CTM 0112, Cured foam sample thickness of 0.317 cm (0.125 inch). |
Thermal Conductivity Test Methods
Thermal Conductivity | Test Method |
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0.41 W/m°K | CTM 069, Cenco Fitch method. |
Volume Resistivity Test Methods
Volume Resistivity | Test Method |
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2.24e15 (ohms/cm) | CTM 0249, Cured foam sample thickness of 0.317 cm (0.125 inch). |
Coefficient of Thermal Expansion (CTE) Test Methods
Coefficient of Thermal Expansion (CTE) | CTE Temperature (°C) | CTE Test Method |
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1.78e-4 (in./ in/°F) | -25 to 150°C | CTM 0585, One part A thoroughly mixed with one part B and cured at 25°C (77°F) for 24 hours. |
Density Test Methods
Density | Test Method |
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Medium | |
0.220 to 0.320 g/cm³ | CTM 0812, Power mixed for 30 seconds and cured in nonconfined condition. |
Specific Gravity Test Methods
Specific Gravity | Temperature | Test Method |
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1.050 to 1.110 | 25°C | CTM 0097 |

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