Scratches in the glass, does it matter to an NMR tube?

We recently had a researcher call us with a problem of tube breakage. He was using a NMR tube washing unit to recycle his NMR tubes, and found that some tubes were breaking very cleanly at specific points along the tubes. After talking to the researcher, he indicated that the NMR tubes were stored in metal racks that had drilled out holes where the tubes were positioned into. At these points of contact, and after being placed into the rack during several cycles of usage, the metal hole portion scratched into the surface of the NMR tube.

Our Norell Technical Service Department informed the customer, that NMR tubes, like any other piece of glassware, become flawed when scratched and will develop a weak spot.

The point to be made, is never store a NMR tube in a metal rack, to prevent scratching on the tubes outer surface, resulting in tube failure.