Seat Insert Kit Molded Foam

The KIRKEY Seat Insert Kit Molded Foam (model 99300) is a two-part expanding foam system designed to create custom-fitted seat cushioning for automotive, marine, and motorsport applications. This molded foam seat insert kit allows users to build a precisely contoured seat from raw materials, delivering support tailored to individual frame geometry and seating position requirements that off-the-shelf cushions cannot match.

The two-part expanding foam formulation expands uniformly to fill the seat pan or frame cavity, then cures to a firm, supportive density. This approach eliminates voids and pressure points that develop in mass-produced seats. The black finish resists staining and UV degradation, maintaining appearance across extended outdoor or high-heat environments. At 11.57 lbs, the complete kit yields substantial material coverage; the kit dimensions of 14.3" × 10.25" × 22.4" accommodate multiple seat profiles or full-coverage applications depending on intended use.

This seat insert system is popular in custom automotive builds, off-road racing platforms, performance watercraft, and restoration projects where OEM seating is unavailable or unsuitable. Users value the ability to dial in lateral support, lumbar contouring, and base firmness without being constrained by pre-molded seat geometries. The KIRKEY brand brings decades of motorsports heritage to foam cushioning technology, recognized for consistent expansion rates and long-term structural integrity under vibration and temperature cycling.

Expanding foam seat inserts represent a cost-effective alternative to upholstered or fiberglass seat shells, especially for single-application or prototype builds. The two-part mix ratio and expansion chemistry are forgiving of minor technique variations, making this kit accessible to builders without professional upholstery experience while still delivering professional-grade support and durability.