How to Determine the Integrity of the Anti-corrosion Layer on a Glue Can

I. Initial Visual Inspection

1. Overall Inspection: Under sufficient light, thoroughly inspect the inner and outer anti-corrosion layers of the can, confirming the absence of visible defects such as cracks, bubbles, peeling, curling edges, and localized wear.

2. Detailed Inspection: Focus on weak points with stress concentration, such as welds, flanges, corners, and connecting pipes, checking for cracks or missing sections in the anti-corrosion layer. These areas are the most vulnerable to damage.

3. Standard Comparison: A qualified anti-corrosion lining should meet the following appearance requirements: a smooth, non-curling surface, a natural transition between old and new adhesive surfaces, and no obvious unevenness or repair marks.

II. Simple Non-Destructive Practical Inspection

1. Hammer Tapping Method: Gently tap the surface of the anti-corrosion layer with a small hammer. A clear, even sound indicates a tight bond between the anti-corrosion layer and the substrate; a hollow or rattling sound indicates internal hollowness or delamination, meaning the anti-corrosion layer is incomplete.

2. Wet Sponge Scanning Method: Under low-pressure conditions, a sponge soaked in conductive liquid is used to sweep across the surface of the thin anti-corrosion layer at a uniform speed. If the associated low-voltage alarm device does not trigger, it indicates that the anti-corrosion layer in that area is free of pinhole damage.

III. Precise Testing with Professional Instruments

1. Spark Leakage Test: This is the core standard method for detecting the integrity of the anti-corrosion layer. A spark detector of the corresponding voltage is moved uniformly along the surface of the anti-corrosion layer. If there is no breakdown spark or alarm, it indicates that the anti-corrosion layer is free of hidden defects such as pinholes and sand holes.

2. Coating Thickness Verification: The thickness of the anti-corrosion layer is measured at multiple points using a thickness gauge to confirm that the thickness is uniform and meets design requirements, with no areas of insufficient thickness, thus avoiding premature failure of the anti-corrosion layer due to insufficient thickness.

IV. Auxiliary Verification Methods

1. Water Pressure Testing Verification: After filling the tank with clean water and sealing it under pressure, it is left to stand for 24 hours. The outer wall of the tank is checked for water leakage or seepage points, indirectly verifying the overall integrity of the anti-corrosion layer seal and the absence of penetrating damage.

2. Medium immersion verification: Fill with the actual amount of corrosive glue to be stored and let stand for 72 hours. After pouring it out, check that the metal substrate is not exposed and has no traces of rust. This will finally confirm that the anti-corrosion layer is intact and effective.