Hercules 15-707 Blue Block Thread and Gasket Sealant – 1/2 Pint

The Hercules 15-707 Blue Block is a high-performance, all-purpose thread and gasket sealing compound formulated for mechanical, plumbing, and industrial systems. Designed for use on both metallic and plastic threaded connections, Blue Block forms a flexible, durable, and pressure-resistant seal that prevents leakage under severe temperature, vibration, and pressure conditions. The compound sets rapidly and remains pliable for easy disassembly of joints, ensuring reliable sealing performance across a wide service range. Suitable for use on water, gas, air, and hydraulic lines, Blue Block is formulated to meet professional standards for chemical stability and mechanical integrity in demanding applications.

Details

• Manufacturer: Hercules (Oatey Company)
• Model Number: 15-707
• Product Name: Blue Block Thread and Gasket Sealant
• Container Type: Metal can with brush-in-cap applicator
• Container Size: 1/2 Pint (237 mL)
• Net Weight: 0.8 lb (363 g)
• Physical Form: Liquid paste
• Color: Blue
• Odor: Alcohol
• Composition:
  • Rosin
  • Castor Oil
  • Isopropyl Alcohol
  • Talc
  • Magnesium Carbonate
  • Mica
  • Titanium Dioxide
  • Amorphous Fumed Silica
  • Crystalline Silica (Quartz)
• Specific Gravity: 1.29
• Viscosity: 12,000 cP
• VOC Content: 183 g/L
• Flash Point: 170°F (77°C)
• Flammability Rating: 2 (moderate)
• Service Temperature Range: -90°F to +450°F (-68°C to +232°C)
• Application Temperature Minimum: +20°F (-7°C)
• Hydraulic Pressure Rating: 12,000 PSI (liquids)
• Gas Pressure Rating: 2,600 PSI
• Applicable Materials: Aluminum, Black Iron, Brass, Copper, Galvanized Steel, Stainless Steel, Monel, Glass, PVC, and CPVC
• Corrosion Resistance: High – non-reactive, non-shrinking sealant
• Toxicity: Lead-free and non-corrosive formulation
• Removal: Can be removed with isopropyl alcohol from tools and surfaces
• Compliance: ORM-D classification for transport; suitable for potable and mechanical system use

Technical Application

Hercules Blue Block Thread and Gasket Sealant is engineered for use in professional piping and equipment assembly where pressure-rated, vibration-resistant, and temperature-stable sealing is required. The compound’s unique formulation provides rapid set-up and high film strength, ensuring long-term performance without hardening or shrinkage. Blue Block adheres to a variety of metallic and non-metallic substrates, allowing use on water lines, compressed air systems, refrigeration piping, hydraulic lines, and fuel or gas systems where applicable. The sealant provides a uniform coating and full thread engagement, preventing leakage caused by thermal expansion or system vibration. It maintains integrity under pressure and temperature cycling, allowing disassembly without damage to threads or fittings.

Specifications

• Type: Non-hardening, all-purpose thread and gasket sealant
• Base Material: Oil and rosin-based compound with mineral and filler additives
• Color: Blue
• Specific Gravity: 1.29
• Viscosity: 12,000 centipoise
• Flash Point: 170°F
• VOC Content: 183 g/L
• Flammability Rating: 2 (moderate)
• Temperature Range: -90°F to +450°F
• Hydraulic Pressure Resistance: 12,000 PSI
• Gas Pressure Resistance: 2,600 PSI
• Applicable Materials: Ferrous and non-ferrous metals, plastics (PVC, CPVC), and composite materials
• Cure Characteristics: Rapid surface set; remains flexible after cure
• Cleanup: Isopropyl alcohol
• Application Temperature Range: +20°F and above
• Compliance: ORM-D classification; lead-free formulation

Application Suitability

• Metal and plastic threaded pipe joints
• Hydraulic and pneumatic system fittings
• Plumbing, heating, and HVAC applications
• Refrigeration and industrial piping systems
• Gasket sealing for pressure-containing components

Installation and Handling

Apply with the supplied natural bristle brush to clean, dry threads. Assemble components to the manufacturer’s recommended torque specifications. Blue Block sets quickly but remains flexible for joint adjustment. It is recommended that assemblies be pressure-tested after installation per applicable code. The compound can be used in ambient conditions down to +20°F and should be stored in sealed containers away from heat sources. Clean tools and surfaces with isopropyl alcohol immediately after use.

Summary

The Hercules 15-707 Blue Block Thread and Gasket Sealant (1/2 Pint) is a high-performance, non-hardening compound designed for professional sealing of metallic and plastic threaded joints. Formulated for strength, flexibility, and vibration resistance, it provides leak-proof performance under pressures up to 12,000 PSI for liquids and 2,600 PSI for gases. With a wide temperature range of -90°F to +450°F and compatibility across diverse materials, Blue Block ensures durable sealing in mechanical, plumbing, and industrial applications requiring reliable joint integrity.