BISCO® HT-1250 General Purpose Solid Silicone Gaskets

SPECIFIC GRAVITY:
1.16 g/cc
DUROMETER, SHORE A [ASTM D2240]:
50 ±5
COMPRESSION SET, 70 HOURS @ 302˚F @ 25% [ASTM D395]:
≤25%
TENSILE STRENGTH [ASTM D412]:
1030 psi
TENSILE ELONGATION [ASTM D412]:
≥200%
HARDNESS CHANGE AFTER HEAT AGING 70 HOURS @ 437˚F [ASTM D573]:
±10 pts
TENSILE STRENGTH CHANGE AFTER HEAT AGING 70 HOURS @ 437˚F [ASTM D573]:
-20%
ELONGATION CHANGE AFTER HEAT AGING 70 HOURS @ 437˚F [ASTM D573]:
-40%
CHANGE IN VOLUME [ASTM D471]:
+5%
CHANGE IN HARDNESS (SHORE A) AFTER OIL IMMERSION 70 HOURS @ 302˚F [ASTM D471]:
-10 to +5 pts
TENSILE STRENGTH CHANGE AFTER OIL IMMERSION 70 HOURS @ 302˚F [ASTM D471]:
-10%
ELONGATION CHANGE AFTER OIL IMMERSION 70 HOURS @ 302˚F [ASTM D471]:
-15%
VOLUME CHANGE AFTER OIL IMMERSION 70 HOURS @ 302˚F [ASTM D471]:
+5 %
A-A-59588:
Compliant
AMS 3301-3305:
Compliant
FDA 21 CFR 177.2600:
Compliant
NSF 51 [File MH62230]:
Compliant

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Product Overview

BISCO® HT-1250 — Solid Silicone (Shore A 50) — Technical Overview & FAQs

Product Overview

BISCO® HT-1250 is a medium-firm solid silicone rubber formulated for durable gasketing, sealing, and vibration isolation. It offers excellent mechanical stability and long-term compression set performance across a wide temperature range. This material is ideal for industrial, transportation, and aerospace applications requiring consistent resilience and environmental resistance.

Applications

Door and panel gaskets for industrial enclosures
Transportation and HVAC sealing
Electrical housing and lighting assemblies
Engineered gaskets for demanding environments

Key Properties

Specific Gravity: 1.16 g/cc
Hardness: 50 ±5 Shore A
Compression Set (70 hrs @ 302°F, 25%): ≤25%
Tensile Strength: 1010 psi
Elongation: ≥300%
Heat Aging (70 hrs @ 437°F): Hardness ±10 pts; Tensile -20%; Elongation -40%
Oil Immersion (70 hrs @ 302°F): Volume +5%; Tensile -10%; Elongation -15%
Compliances: A-A-59588, AMS 3301–3305, FDA 21 CFR 177.2600, NSF 51

FAQs

What makes HT-1250 different from softer grades?
HT-1250 provides greater dimensional stability under load, making it ideal where firmer compression support is needed.

Can HT-1250 withstand high temperatures?
Yes — it performs continuously up to 450°F (232°C) and resists heat aging and ozone degradation.

Is it safe for food-contact applications?
Yes — it meets FDA 21 CFR 177.2600 and NSF 51 compliance standards.

Can you supply HT-1250 in adhesive-backed rolls?
Yes — it’s available with high-performance silicone or acrylic PSAs for easy application.

How does it perform in vibration isolation?
The 50A hardness offers an optimal balance of damping and structural integrity for dynamic load applications.

Request BISCO® HT-1250 samples or custom gasket quotes from H-O Products today - contact us.