3M Premium 2-Component Casting Resin 40 A – 1L Polyurethane Casting Compound for Electrical Encapsulation

With a dielectric strength exceeding 20 kV/mm, this 3M Premium 2-Component Casting Resin 40 A delivers exceptional electrical insulation for demanding potting and encapsulation tasks. Its 1:1 mixing ratio by volume and low-to-medium viscosity ensure easy processing and reliable penetration into complex cavities, while the transparent amber finish allows visual inspection of embedded components.

Overview

Engineered for professionals, this polyurethane resin cures to a Shore A 40 hardness, providing a flexible yet durable protective barrier. The kit includes 1 liter total volume (500 ml resin + 500 ml hardener) and offers a pot life of 20–30 minutes at 23°C, with full cure achieved in approximately 24 hours. It excels in sealing, insulation, and encapsulation of electronic assemblies, connectors, and sensors.

What stands out

• High dielectric strength >20 kV/mm for superior electrical insulation
• Self-extinguishing formulation enhances fire safety
• Excellent water resistance and good chemical resistance to acids, alkalis, and oils
• Wide operating temperature range from -40°C to +90°C
• RoHS compliant and 24-month shelf life for long-term storage

Technical details

• Product type: 2-Component Polyurethane Resin
• Hardness: Shore A 40
• Mixing ratio (by volume): 1:1
• Pot life at 23°C: approx. 20–30 minutes
• Cure time at 23°C: approx. 24 hours (full cure)
• Density (mixed): approx. 1.05 g/cm³
• Viscosity (mixed): low to medium
• Flammability rating: self-extinguishing
• UV resistance: moderate
• Chemical resistance: good against common acids, alkalis, and oils
• RoHS compliant: yes

Our verdict

A reliable, high-performance potting compound that combines easy processing with robust electrical and environmental protection—ideal for both prototyping and production runs.