Spray a mixture of alcohol and ketone soluble fluorescent powder onto the inner wall of the lamp tube with water, allowing it to dry naturally. Glue coating involves spraying a mixture of glue and fluorescent powder, and then drying it in an oven. Its viscosity and fastness are greatly superior to those of water coated powder tubes. Most advanced countries use three primary colors of lead coated glass tubes to produce neon lights, and some manufacturers in China have already used this type of neon tube.