BISCO® HT-1250
50 Shore A General Purpose Solid Silicone
BISCO® HT-1250 is a 50 ±5 Shore A solid silicone elastomer engineered for applications requiring balanced flexibility and structural support under sustained compression and elevated temperature exposure. Rated from −80°F to 425°F, HT-1250 maintains ≤25% compression set after 70 hours at 302°F, supporting reliable long-term sealing performance.
Key Properties
- Hardness: 50 ±5 Shore A
- Tensile Strength: 1030 psi
- Elongation: ≥200%
- Compression Set: ≤25% (70 hrs @ 302°F, 25%)
- Specific Gravity: 1.16 g/cc
- Recommended Service Temperature: −80°F to 425°F
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Material | Solid Silicone | — |
| Specific Gravity | 1.16 g/cc | ASTM D2240 |
| Thicknesses Available | 0.031″, 0.063″, 0.094″, 0.125″ | — |
| Colors | Red, Black, Gray, White | — |
Mechanical Properties
| Property | Value | Test Method |
| Durometer | 50 ±5 Shore A | ASTM D2240 |
| Tensile Strength | 1030 psi | ASTM D412 |
| Elongation | ≥200% | ASTM D412 |
| Compression Set (70 hrs @ 302°F, 25%) | ≤25% | ASTM D395 |
Heat Aging Performance
(70 Hours @ 437°F)
| Property Change | Value | Test Method |
| Hardness Change | ±10 pts | ASTM D573 |
| Tensile Change | −20% | ASTM D573 |
| Elongation Change | −40% | ASTM D573 |
Oil Immersion Performance
(70 Hours @ 302°F)
| Property Change | Value | Test Method |
| Hardness Change | −10 to +5 pts | ASTM D471 |
| Tensile Change | −10% | ASTM D471 |
| Elongation Change | −15% | ASTM D471 |
| Volume Change | +5% | ASTM D471 |
Environmental Performance
| Property | Value | Test Method |
| Low Temperature Brittleness | Pass | ASTM D2137 |
| Recommended Use Temperature | −80°F to 425°F | — |
Compliance
- A-A-59588 — Compliant
- AMS 3301–3305 — Compliant
- FDA 21 CFR 177.2600 — Compliant
- NSF 51 — Compliant (File MH62230)
- Environmental enclosure gasketing
- Access panel seals
- Equipment housing seals
- Fluid-exposed static sealing
- Thermal exposure sealing components
Common industries: aerospace, automotive, electronics, industrial equipment, and regulated processing environments.
HT-1250 is the balanced, general-purpose grade within the HT-1200 series. Its 50 Shore A hardness provides a controlled combination of conformability and load-bearing support, making it suitable for applications requiring predictable compression retention and dimensional stability.
The material demonstrates controlled mechanical change after heat aging and oil immersion testing, supporting use in industrial environments exposed to thermal cycling and fluid contact.
Compliant with A-A-59588, AMS 3301–3305, FDA 21 CFR 177.2600, and NSF 51.
What differentiates HT-1250 from other HT-1200 grades?
HT-1250 offers moderate firmness at 50 Shore A, providing a balance between surface conformity and structural support.
Why is compression set critical?
Compression set measures long-term recovery after sustained compression. Lower values support improved sealing retention over time.
What is the operating temperature range?
−80°F to 425°F.
Is HT-1250 suitable for regulated environments?
Yes. It complies with aerospace and food-contact related standards listed above.
How should this material be specified?
Specify grade (HT-1250), thickness, color, compliance requirements, dimensional tolerances, and finished format.
