What is an eddy current exam?
This examination uses a tiny current of electricity and is performed on some types of aluminum SCUBA cylinders to assist in the detection of cracks in the threaded neck area. It alerts the inspector to specific locations on the neck threads that need further evaluation. The devices using eddy current technology are sold under the brand names Visual Plus, Visual Eddy, and Simple Eddy. The exam is notorious for false positives as a result of poor operator technique and is intended only to supplement, not replace, the visual inspection. Luxfer recommends eddy current tests be performed only on their aluminum cylinders made from 6351-T6 alloy. However, many dive shops require an annual eddy current exam on all aluminum cylinders before filling, regardless of the type of alloy. Eddy current exams are not meaningful on any type of steel.
