First, measure thickness of the cap seal, the most common thickness of drum cap seals are 0.25mm to 0.32mm, varies according to customers’ requirement. If the thickness of cap seals are lower than it, the anti-leakage and bearing capacity may not meet the standards.
Second, scratch the coating of the cap seal surface, to see whether fall off easily. High quality painting results in a uniform, glossy finish that will not be easily damaged.
Third, look inner side of cap seal gasket, the gasket around the cap seal is uniform in thickness and clean white in color.
Finally, use crimping tool to install the cap seals on the drum closure and to see whether it is closed tightly. If it can be easily teared off, the cap seals is not with good production standard.