Many customers new to custom aluminum cans often ask: "Is it mandatory to coat aluminum cans internally? Wouldn't skipping the internal coating be cheaper?"

In fact, this is a very typical question. Technically speaking, aluminum cans can indeed be uncoated (bare cans). However, if you choose not to coat them, you must first solve the physical challenge of the roughness and unevenness inside the can. This process adds production steps, extends labor time, reduces efficiency, and the costs are almost offset by adding the internal coating. Therefore, most standard orders opt for internal coating.

• Uncoated (Bare Can): To improve the flatness of the can's interior to accommodate a bare state, additional finishing processes (such as inner wall polishing or special treatment) are required. This not only increases equipment wear but also significantly extends the production cycle.
• Coated: Although it adds the process of painting and drying, the internal coating itself has a smoothing effect, which can cover minor imperfections during stretching and forming, thereby simplifying pre-processing steps and improving production efficiency.
  Therefore, in regular mass production, the total cost of a coated can is often not higher than that of an uncoated one, and sometimes even lower.

 

• Chemical Isolation: Propellants (like DME) or solvents (like alcohol, ketones) in aerosols may react chemically with aluminum, causing corrosion, perforation, or off-flavors. The internal coating (usually Epoxy-Phenolic resin) acts as a barrier, isolating the metal from the contents.
• Food Safety: For aerosol products related to food-grade or cosmetic-grade applications, internal coating is a crucial safeguard for food safety regulations, prnting aluminum ion mievegration into the product.

 

• Scenario: Very short shelf life (e.g., disposable lighters), chemically stable contents (e.g., petroleum-based fuels), and huge order volumes (e.g., bulk purchases by lighter factories).
• Advantage: In these specific scenarios, since the contents do not corrode the aluminum can, and large-scale production can spread the mold and process costs, not having an internal coating can indeed reduce the cost slightly.
• Risk: Once the product formula changes or storage conditions vary, the bare aluminum can is highly prone to rust, making the risk uncontrollable.

 

1. Most cases (especially for cosmetic, pharmaceutical, and food aerosols): Strongly recommend coated cans.​ This is the safest, most stable, and compliant choice.
2. Specific cases (like lighter fluid, industrial solvents, ultra-large-scale low-cost orders): Uncoated cans can be considered.​ But be sure to conduct small-batch tests to ensure the product coexists with the bare can without reacting over time.
3. Don't give up internal coating just to save a little money, unless you fully understand your product's properties and market plans for the next few years.