Paint on the inner surface of the process water tank
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May I ask, should only an anti-rust primer be applied to the inner surface, or are intermediate coat and top coat also necessary?
Carbon steel usually has two bottoms and one top. Epoxy resin is the best choice for the topcoat as it offers strong water resistance. These days, they’re mostly galvanized or made of stainless steel directly
This is a carbon steel water tank used in the desulfurization system of a power plant. The main project specifications require that the surface of the steel, which is not insulated, be coated with one bottom coat and two intermediate coats plus three top coats; the bottom coat is red lead alkyd anti-rust paint, while the top coats are three layers of alkyd enamel. Do the inner surface also need to have so many coats of paint?
What I explained above is the most conventional, ordinary, and simplest type of water tank. If the agreement requires it, it is recommended to do so. Enamel has high hardness and strong weather resistance. 1/2/3 is also quite common; I used to mark it as 2/3/3. Many bidding documents also specify thickness requirements. The inner surface of the water tank is in direct contact with the medium; if not handled properly, it will cause corrosion of carbon steel, significantly reducing its lifespan and posing safety risks as well.
Okay, thank you for the detailed explanation. I used to think that the inner surface only needed to be coated with a primer.
You’re welcome; we learn from each other.*
Everything is carried out in accordance with the contract terms; this ensures there is a basis for action and avoids liability. Care must be taken when applying anti-corrosion paint inside water tanks; the poor quality of some paints can lead to peeling, causing problems in production. Therefore, attention should also be paid to quality assurance in procurement. For reference.