A High-Performance Foam for Insulation and Sealing

BISCO HT-840 is an extra-firm silicone foam that provides excellent insulation, sealing, vibration dampening and noise reduction. This versatile foam can be used in a variety of industrial, construction, transportation and appliance applications.

Key Features of BISCO HT-840

• Extra-firm foam that resists compression
• Low thermal conductivity for insulation
• Excellent sealing against water, dust and air infiltration
• Vibration dampening up to 40%
• Noise reduction rating (NRR) of 27 dB
• Withstands extreme temperatures from -65F to 400F
• Low volatile organic compounds (VOCs)

Typical Applications

BISCO HT-840 is suitable for the following typical applications:

• Sealing gaps, joints, penetrations
• Insulating pipes, ducts, equipment
• Isolating vibration in machinery and appliances
• Reducing equipment noise
• Filling voids and cavities

Application	Benefits
Appliances	Insulates and reduces noise from compressors and motors
HVAC Ducts	Seals joints and insulates ducts
Automotive	Dampens engine vibration and insulates components
Marine Craft	Waterproofs, insulates and reduces engine noise

How to Use

BISCO HT-840 is easy to apply directly from the can or cartridge. Prepare surfaces by cleaning and removing any oils or grease. Fill voids at least 50% full to allow for expansion during cure.Dispense foam and allow it to fully cure for 24 hours before trimming or sanding. Wear gloves and eye protection when handling.

Frequently Asked Questions

Q: Does BISCO HT-840 contain any VOCs?

A: Yes, BISCO HT-840 contains a low level of VOCs, but is still VOC compliant in all 50 states.

Q: What temperature range can it withstand?

A: BISCO HT-840 can withstand extreme temperatures from -65F to 400F once fully cured.

Q: How long does the foam take to cure?

A: It typically cures tack-free in 30-45 minutes and fully cures in 24 hours. Cure times vary based on temperature and humidity.

Q: Can I apply over paint or coatings?

A: Yes, BISCO HT-840 bonds well to most common surfaces including wood, metal, plastics and previously applied paints.

Q: Is the foam resistant to oils or gasoline?

A: While it has good chemical resistance, BISCO HT-840 is not recommended for direct contact with oils or gasoline. It is better suited for water, dilute acids and bases.

BISCO HT-840 is an exceptional extra-firm silicone foam for demanding insulation, sealing and noise reduction applications. Its versatility and performance make it a top choice for OEMs, contractors and do-it-yourselfers. Be sure to follow the usage guidelines to get the best results from this high-quality foam.