No, it is not safe to buy and use recycled aluminum coils without first checking their quality. Recycled aluminum coils may have inconsistencies in thickness, strength, and purity, which can affect the performance and safety of the final product. It's crucial to inspect the coils for any defects, impurities, or deviations from the required specifications to ensure they meet the standards necessary for your application. Quality control is essential to prevent failures, maintain safety, and uphold the integrity of your manufacturing process.