Mastercool 90935 Alum Bond Aluminum Repair Compound – High-Strength, Machinable Epoxy for Castings, Radiators & Engine Components

Overview

Meet Mastercool 90935 Alum Bond, an aluminum-filled repair compound designed for permanent, high-strength fixes on aluminum components. This durable repair solution blends a rigid resin with aluminum filler to address casting imperfections, leaks, and surface flaws. Designed for radiators, engine blocks, housings, tanks, and HVAC parts, Alum Bond aims to help technicians restore functionality without immediate part replacement.

Key features and specifications

• ALUMINUM-FILLED METAL REPAIR COMPOUND – Professional-grade aluminum-filled polymer designed to permanently repair cracks, blow holes, and casting imperfections in aluminum components including radiators, engine blocks, housings, tanks, and HVAC parts.
• HIGH-STRENGTH INDUSTRIAL PERFORMANCE – Engineered for demanding repairs with approximately 8,600 PSI compressive strength and 3,500 PSI tensile strength, creating a durable repair capable of restoring damaged aluminum surfaces.
• MACHINABLE AFTER CURING – Once fully cured, the repair compound can be drilled, sanded, tapped, or machined using standard metalworking tools, allowing technicians to restore functionality without replacing expensive components.
• NON-SAG FORMULA FOR VERTICAL APPLICATIONS – Thick paste consistency allows Alum Bond to stay in place during application, making it ideal for filling cavities, blow holes, porosity, and irregular surfaces on vertical or overhead repairs.
• HIGH TEMPERATURE RESISTANCE – Designed for automotive, HVAC, and industrial environments with temperature resistance up to 250°F (121°C) after full cure.
• CONTROLLED WORKING TIME FOR PRECISE REPAIRS – Provides a practical working window depending on temperature conditions, allowing technicians time to properly apply and shape repairs before curing.
• IDEAL FOR CASTING DEFECT AND SURFACE REPAIRS – Specifically designed for repairing aluminum castings, radiators, tanks, valves, pumps, engine blocks, and HVAC components where surface defects or porosity require permanent repair.
• TRUSTED MASTERCOOL PROFESSIONAL QUALITY – Mastercool products are designed for professional technicians and supported by a trusted U.S.-based company known for reliable automotive and HVAC service tools.

Real-world scenarios

In a repair shop, technicians may address porosity on an aluminum radiator tank or fill a crack in an engine block casting. The non-sag formula helps the repair stay in place during vertical or overhead applications, while the machinable capability enables precise finishing after curing.

For HVAC components, Alum Bond can seal minor porosity and surface defects, offering a serviceable option before a full replacement, depending on part condition and operating demands. The 250°F cure temperature provides a practical buffer in typical automotive and industrial environments.

Shopping considerations

Think of Alum Bond as a repair option that emphasizes staying in place, strengthening damaged areas, and delivering a machinable finish. It is presented as a professional-grade solution to support permanent-looking repairs without immediate component replacement. Outcomes depend on surface prep, fit, and operating conditions.