Ship castings, anchors and ship casting cabins are often subject to friction and seawater corrosion, which can easily lead to relatively serious rust. Therefore, it is stipulated that building coatings have the functions of wear resistance, seawater resistance and rust prevention. Generally, the architectural coating is methyl acetate finish, which is usually sprayed for 2-3 times, and the dry film thickness exceeds 60 μ M above.

In ship application, it is required to repair the paint layer immediately if it falls due to bumps. In a dry natural environment, the edge of the old paint layer is polished with sandpaper to remove dust and waste. The method of painting is used to carefully spray the asphalt architectural coating on the marine casting. The second layer is sprayed 24 hours later and can be applied after 5 days. It is not necessary to drag and pile up the partially dry marine casting during the period.

Shot blasting or organic chemical pickling and passivation can be selected for the metal surface treatment of newly built marine castings. Many shipyards use the rolling method to prevent rust. The ship castings are tied with fine iron wires to a speed of more than 3m and put into the barrel. The barrel is filled with stainless steel wire forging, carborundum, copper scrap, etc. The barrel is driven by the motor to rotate. The ship castings are knocked by wear-resistant materials to remove rust. Remove the rust and smoke in the cylinder and on the marine casting, and only paint. Generally, it can be hoisted into the paint dripping cylinder to carry out spraying process engineering construction. After 3-5 minutes, it will be dry. The short spraying interval is 24 hours, and the general spraying process is 3.

Solvent cleaning is the main method to remove oil on the surface. Some solvent based paints can dissolve the thin grease deposits on the surface, making them mixed with the paint without any adverse effects. However, it is not applicable to heavy oil grease deposition, aqueous coatings and solvent-free coatings. The solvent cleaning is usually done with a rag, which can be replaced frequently once it is dirty.

New solvent, such as naphtha, is generally used for the latter cleaning. It is strictly prohibited to contact eyes or skin with organic solvents, sparks or open flames nearby, and unnecessary inhalation. The metal after solvent cleaning generally needs to be cleaned again before painting.

Sand blasting is usually a good method for surface treatment of steel or metal. Compared with other cleaning methods, sand blasting method will significantly increase the service life of painting. High speed sand blasting particles can remove all rust, scale, dust and old paint except for grease that must be cleaned by solvent method before sand blasting.

The sandblasting method also produces enough roughness to facilitate the adhesion of paint. Soft sand blasting (such as plastic particles) is required for aluminum or other soft metals to remove old paint without damaging the metal surface. Concrete sandblasting must be handled carefully to avoid damage to buildings.