The material of felt is pure natural wool. The most direct way to distinguish is to rub some wool from the felt and light it with fire. The wool smokes and bubbles during the incineration process. The incinerator has the taste of burning hair. After burning, the embers are black and crisp, and there is no coke like substance. From the exterior investigation, pure felt feels soft and elastic, and the texture is fine and regular. In contrast, chemical fiber felt is made of wool and chemical fiber, and its price is lower than that of pure felt. Its properties are characterized by pure felt insulation and softness. Chemical fiber felt can also be burned by the taste and ash to distinguish the proportion of its material, from the sense of touch can not distinguish static electricity as the top grade.
Selection methods and specifications of felt implied that the number of T, felt density of gram / cm 3, too high density will be inelastic, too small density will reduce its wear resistance, different uses to choose different densities of information. The key to distinguish the best felt from the ordinary felt is the density, thickness, gloss, strength and elongation of the wool. Felt number is composed of five digits of commodity color + material type + species + density + density. Felt should be numbered according to the specifications when making, and the area, thickness and drawings of commodities in demand should be supplied.