Chair Pads and Cushions
Any of these are easily cut with an electric knife.

Best Quality Cushions: Durable and resilient, constructed of our premium foam with a density that prevents collapsing. These cushions will keep their shape and keep your finished project beautiful through high use and time. They are ready to cover.
Light blue color. Inherently Fire Retardant (CA code 117)
Density 2.5 Compression 50 (ILD)

Good Standard Poly Cushions: Excellent foam cushion for area's that receive light residential use. Ready to be covered cushions.
Not fire retardant. Off white color.
Density 1.1 Compression 36 (ILD)

Chair Pad Foam Cores: 15" x 17" in either 1" or 2". Constructed of our Good Poly Foam. Not fire retardant. Off white color.
They are ready to cover. If this is not the same size or shape as the chair or pattern you are using these chair pads are easily cut with a sharp pair of scissors.

Numerous commercial patterns exist to make new covers for kitchen chair seats and backs, rocker seats or backs. Patterns can be found at Simplicity.com or McCallPattern.com