Different measures can be taken to clean the old paint mold on the surface of the component according to the different conditions of the paint film. Specific measures include:
1. If the old paint film is solid and complete, and the component surface adheres well, the impurities on the surface of the old paint film can be removed with soap water or dilute alkali water, washed and dried with clear water, and then painted after
2. If most of the old paint film is well attached to the components, and some parts need to be removed, in addition to cleaning according to the above methods, the process of puttying, polishing, paint repair, etc. shall also be carried
out to make sure that the old paint film is flat and consistent, and the color is the same.
3. If most of the old paint film has been damaged and fallen off, it needs to be completely removed. The removal methods are as follows:
1) Fire spraying:
that is, after the paint film is burned with the torch flame, it is immediately scraped off with a blade. This method is generally used to clean the old paint film with small area.
2) Alkaline water cleaning method: Brush 3-4 times with the dilute
solution of lime and soda ash or 5% - 10% (mass fraction) sodium hydroxide solution. The old paint film is wrinkled and peeled off, then scraped off with a blade and washed with clear water.
3) Brush paint remover method: brush the paint remover
sold on the market on the old paint film. After about half an hour, the old paint film will swell and wrinkle. Use the blade and wire brush to remove the old paint film and other sundries on the component surface.
4) Paint depainting paste method:
apply depainting paste on the surface of the old paint film for 2-3 layers, about 2-3 hours, the paint film is damaged, and clean it with water after being removed with a blade. If the old paint film is too thick, in order to shorten the soaking time,
you can first use a knife to break the old paint film through a proper number of holes, and then apply paint remover.