BrandNewCake Palette Knife/Glaze Knife 20cm The BrandNewCake Palette Knife/Glaze Knife 20cm has a size of 20 centimetres and a plastic handle. Other names of a palette knife include spatula or glazing knife. A palette knife is a handy tool for decorating, masking and even filling cakes. You can use fit knife very well to spread jam, whipped cream, swiss cream or buttercream, among other things. This palette knife has an ideal size for working on both larger and somewhat smaller bakes.