kSil® US350
kSil® US350 is a lightweight, closed cell silicone sponge with a density of 300 kg/m³ and a compression force deflection of 48 kPa, approved to Aerospace Material Specification AMS 3195. It is rated for service from -60°C to +230°C, passes FAR 25.853 Horizontal flame resistance at both 12 and 60 seconds, and exhibits water absorption of less than 5%. The material is available in thicknesses from 1.6 mm to 25.0 mm.
Key Properties
- Compression Force Deflection: 48 kPa (ASTM D1056)
- Tensile Strength: 1034 kPa (ASTM D412)
- Elongation: 300% (ASTM D412)
- Compression Set: 8% (ASTM D1056)
- Density: 300 kg/m³ (ASTM D1056)
- Operating Temperature Range: -60°C to +230°C
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Density | 300 kg/m³ | ASTM D1056 |
| Minimum Thickness | 1.60 mm | — |
| Maximum Thickness | 25.00 mm | — |
| Colors Available | Red-orange | Visual |
Mechanical Properties
| Property | Value | Test Method |
| Compression Force Deflection | 48 kPa | ASTM D1056 |
| Compression Set | 8% | ASTM D1056 |
| Tensile Strength | 1034 kPa | ASTM D412 |
| Elongation | 300% | ASTM D412 |
| Water Absorption | <5% | ASTM D1056 |
Thermal Properties
| Property | Value | Test Method |
| Min Operating Temperature | -60°C | — |
| Max Operating Temperature | 230°C | — |
Flame & Fire Performance
| Property | Value | Test Method |
| UL94 V-0 | Fail | UL94 (File #E83967) |
| Flame Resistance @ 12 Sec | Pass | FAR 25.853 |
| Flame Resistance @ 60 Sec | Pass | FAR 25.853 |
| Toxic Gas Emissions Rating | Fail | SMP-800C @ 1.5/4.0 min |
Compliance
- AMS 3195 — Compliant
- FAR 25.853 Horizontal — Compliant
- Aerospace gaskets and seals requiring AMS 3195 qualification and FAR 25.853 horizontal flame compliance
- Die-cut gaskets for flexible sealing in extreme temperature environments
- Flexible sealing solutions across a wide service temperature range of -60°C to +230°C
- Automotive sealing components evaluated for FMVSS 302 compliance
- Industrial sealing applications requiring closed cell silicone sponge with high tensile strength and low compression set
Common industries: Aerospace, Automotive, Industrial Manufacturing.
kSil® US350 is a closed cell silicone sponge in the kSil® US series, approved to AMS 3195 for aerospace applications. With a density of 300 kg/m³ and a compression force deflection of 48 kPa, it provides a firm sealing profile suited to aerospace gaskets, die-cut seals, and flexible sealing solutions across extreme temperature and environmental conditions. AMS 3195 qualification positions it for use in demanding aerospace programs requiring material traceability.
The US350 delivers a tensile strength of 1034 kPa and an elongation of 300% per ASTM D412, with a compression set of 8% per ASTM D1056 — indicating strong long-term elastic recovery. Water absorption is less than 5%. FAR 25.853 horizontal flame resistance is passed at both 12 and 60 seconds. UL94 V-0 and SMP-800C toxic gas emissions testing did not pass as recorded on the TDS. The material is available in sheets and rolls with widths up to 36″, with a Pressure Sensitive Adhesive (PSA) option. Standard colour is red-orange.
Compliant with AMS 3195 and FAR 25.853 Horizontal. FMVSS 302 compliance is referenced in the typical applications section of the TDS.
What differentiates US350 from GP-series grades with similar density in the kSil® range?
US350 is approved to AMS 3195 — a qualification not carried by GP-series grades — and passes FAR 25.853 Horizontal flame resistance at both 12 and 60 seconds, which the GP200 grade does not. With a tensile strength of 1034 kPa and a compression set of 8%, it also outperforms the GP350 (750 kPa, 5%) in tensile strength while offering comparable compression set performance, along with aerospace material traceability.
Why is compression set critical for cellular silicone sponge materials?
Compression set measures the permanent deformation remaining after a material has been held under compressive load. For aerospace and industrial gasket applications, a low compression set indicates that the sponge will maintain effective contact pressure against mating surfaces over the service life of the seal. US350 exhibits a compression set of 8% per ASTM D1056.
What is the operating temperature range for US350?
US350 is rated from -60°C to +230°C.
Is US350 suitable for aerospace or flame-rated environments?
Yes. US350 is approved to AMS 3195 and passes FAR 25.853 Horizontal flame resistance at both 12 and 60 seconds. UL94 V-0 and SMP-800C toxic gas emissions tests are recorded as Fail on the TDS. Applications requiring those specific ratings should evaluate alternative grades.
How should US350 be specified?
Specify grade (US350), thickness, PSA option if required, compliance requirements (AMS 3195, FAR 25.853), dimensional tolerances, and finished format.
